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https://exercises.lol/videos/oxford_aqa_igcse_mathematics2026-10-29 https://exercises.lol/videos/oxford_aqa_igcse_physics2026-10-30 https://exercises.lol/videos/sat2026-11-08 https://exercises.lol/videos/toefl2026-10-30 https://exercises.lol/videos/a2_key/key-reading-messages-and-short-texts2026-10-30https://exercises.lol/video-media/a2_key/key-reading-messages-and-short-texts/key-reading-messages-and-short-texts.thumb.jpg?v=1793398438A2 Key · Reading Parts 1–3: messages and short textsA2 Key starts with three reading parts built from real-world texts. Part one: six short notices or messages. Part two: three short texts on the same topic and…https://exercises.lol/video-media/a2_key/key-reading-messages-and-short-texts/key-reading-messages-and-short-texts.enzh.mp4?v=1793398438-22802026-10-08yes https://exercises.lol/videos/a2_key/key-cloze-vocabulary-and-grammar2026-10-30https://exercises.lol/video-media/a2_key/key-cloze-vocabulary-and-grammar/key-cloze-vocabulary-and-grammar.thumb.jpg?v=1793399196A2 Key · Parts 4–5: the clozeParts four and five are the cloze: a short text with gaps. Part four gives three word choices per gap and tests vocabulary. Part five gives six gaps in a short…https://exercises.lol/video-media/a2_key/key-cloze-vocabulary-and-grammar/key-cloze-vocabulary-and-grammar.enzh.mp4?v=1793399196-22212026-10-08yes https://exercises.lol/videos/a2_key/key-writing-the-message2026-10-30https://exercises.lol/video-media/a2_key/key-writing-the-message/key-writing-the-message.thumb.jpg?v=1793398415A2 Key · Writing Part 6: the 25-word messagePart six is a short message of at least twenty-five words, answering a friend's message, and the friend's message always contains three things to do. The…https://exercises.lol/video-media/a2_key/key-writing-the-message/key-writing-the-message.enzh.mp4?v=1793398415-22322026-10-08yes https://exercises.lol/videos/a2_key/key-writing-picture-story2026-10-30https://exercises.lol/video-media/a2_key/key-writing-picture-story/key-writing-picture-story.thumb.jpg?v=1793392520A2 Key · Writing Part 7: the three-picture storyPart seven: write a short story of at least thirty-five words from three pictures — a beginning, a middle and an end. Look at all three pictures before…https://exercises.lol/video-media/a2_key/key-writing-picture-story/key-writing-picture-story.enzh.mp4?v=1793392520-22722026-10-08yes https://exercises.lol/videos/a2_key/key-listening-visual-notes-conversations2026-10-29https://exercises.lol/video-media/a2_key/key-listening-visual-notes-conversations/key-listening-visual-notes-conversations.thumb.jpg?v=1793317618A2 Key · Listening Parts 1–3: pictures, notes and conversationsThe A2 Key listening paper runs about thirty minutes, five parts, and every recording plays twice. Part one: picture questions. Part two: note gaps. Part…https://exercises.lol/video-media/a2_key/key-listening-visual-notes-conversations/key-listening-visual-notes-conversations.enzh.mp4?v=1793317618-22502026-10-08yes https://exercises.lol/videos/a2_key/key-listening-gist-and-matching2026-10-30https://exercises.lol/video-media/a2_key/key-listening-gist-and-matching/key-listening-gist-and-matching.thumb.jpg?v=1793398630A2 Key · Listening Parts 4–5: gist and matchingParts four and five change the question. Parts one to three asked for details; parts four and five ask for the gist — the main idea, the speaker's feeling, the…https://exercises.lol/video-media/a2_key/key-listening-gist-and-matching/key-listening-gist-and-matching.enzh.mp4?v=1793398630-22102026-10-08yes https://exercises.lol/videos/a2_key/key-speaking-interview-and-discussion2026-10-30https://exercises.lol/video-media/a2_key/key-speaking-interview-and-discussion/key-speaking-interview-and-discussion.thumb.jpg?v=1793392959A2 Key · Speaking: the interview and the discussionThe speaking test is eight to ten minutes, with a partner and two examiners, and it is the friendliest part of the exam: a conversation, not an interrogation.…https://exercises.lol/video-media/a2_key/key-speaking-interview-and-discussion/key-speaking-interview-and-discussion.enzh.mp4?v=1793392959-22362026-10-08yes https://exercises.lol/videos/a_level_biology/cells2026-10-30https://exercises.lol/video-media/a_level_biology/cells/cells.thumb.jpg?v=1793367911How We Study CellsYou are built from about thirty trillion cells, yet you have never seen a single one. Cells are simply too small for the eye. A grain of sand is about a…https://exercises.lol/video-media/a_level_biology/cells/cells.enzh.mp4?v=1793367911-29852026-08-15yes https://exercises.lol/videos/a_level_biology/biological-molecules2026-10-28https://exercises.lol/video-media/a_level_biology/biological-molecules/biological-molecules.thumb.jpg?v=1793185891Biological MoleculesSuppose you have an unknown food sample. How do you tell what it is made of? Biology has a beautiful trick: add the right chemical, and the colour tells you…https://exercises.lol/video-media/a_level_biology/biological-molecules/biological-molecules.enzh.mp4?v=1793185891-211722026-08-15yes https://exercises.lol/videos/a_level_biology/enzymes2026-10-29https://exercises.lol/video-media/a_level_biology/enzymes/enzymes.thumb.jpg?v=1793271596EnzymesInside every cell, thousands of chemical reactions happen every second — far faster than they ever could on their own. The secret is a special kind of protein…https://exercises.lol/video-media/a_level_biology/enzymes/enzymes.enzh.mp4?v=1793271596-28312026-08-15yes https://exercises.lol/videos/a_level_biology/cell-membranes2026-10-28https://exercises.lol/video-media/a_level_biology/cell-membranes/cell-membranes.thumb.jpg?v=1793192609Cell MembranesEvery cell must keep the right things in and the wrong things out. That job falls to a single, astonishingly thin layer — the cell surface membrane, just two…https://exercises.lol/video-media/a_level_biology/cell-membranes/cell-membranes.enzh.mp4?v=1793192609-28412026-08-15yes https://exercises.lol/videos/a_level_biology/mitosis2026-10-28https://exercises.lol/video-media/a_level_biology/mitosis/mitosis.thumb.jpg?v=1793186615MitosisRight now, inside you, millions of cells are dividing. A cell grows, copies everything it contains, and splits into two — and the two daughter cells are not…https://exercises.lol/video-media/a_level_biology/mitosis/mitosis.enzh.mp4?v=1793186615-24402026-08-15yes https://exercises.lol/videos/a_level_biology/dna-protein-synthesis2026-10-29https://exercises.lol/video-media/a_level_biology/dna-protein-synthesis/dna-protein-synthesis.thumb.jpg?v=1793305778DNA & Protein SynthesisInside almost every one of your cells sits a molecule about two metres long, folded up so tightly you cannot see it. It is DNA, and it is written in an…https://exercises.lol/video-media/a_level_biology/dna-protein-synthesis/dna-protein-synthesis.enzh.mp4?v=1793305778-25762026-08-15yes https://exercises.lol/videos/a_level_biology/transport-in-plants2026-10-28https://exercises.lol/video-media/a_level_biology/transport-in-plants/transport-in-plants.thumb.jpg?v=1793186043Transport in PlantsA giant redwood lifts water more than a hundred metres into the air, every single day — and it has no heart, no muscle, no pump of any kind. So what does the…https://exercises.lol/video-media/a_level_biology/transport-in-plants/transport-in-plants.enzh.mp4?v=1793186043-25162026-08-15yes https://exercises.lol/videos/a_level_biology/circulatory-system2026-10-30https://exercises.lol/video-media/a_level_biology/circulatory-system/circulatory-system.thumb.jpg?v=1793330688The Circulatory SystemYour heart beats about a hundred thousand times a day, and it never gets a day off. But here is the clever part. It is not one loop. It is two. Blood leaves…https://exercises.lol/video-media/a_level_biology/circulatory-system/circulatory-system.enzh.mp4?v=1793330688-25562026-08-15yes https://exercises.lol/videos/a_level_biology/gas-exchange2026-10-29https://exercises.lol/video-media/a_level_biology/gas-exchange/gas-exchange.thumb.jpg?v=1793290672The Gas Exchange SystemSpread the inside of your lungs out flat and it would cover about seventy square metres — roughly half a tennis court. That whole area is folded up inside your…https://exercises.lol/video-media/a_level_biology/gas-exchange/gas-exchange.enzh.mp4?v=1793290672-24182026-08-15yes https://exercises.lol/videos/a_level_biology/infectious-disease2026-10-28https://exercises.lol/video-media/a_level_biology/infectious-disease/infectious-disease.thumb.jpg?v=1793196813Infectious DiseaseThe animal that kills the most people every year is not the shark or the snake. It is the mosquito. And the strange thing is that the mosquito itself does…https://exercises.lol/video-media/a_level_biology/infectious-disease/infectious-disease.enzh.mp4?v=1793196813-25082026-08-15yes https://exercises.lol/videos/a_level_biology/immunity2026-10-29https://exercises.lol/video-media/a_level_biology/immunity/immunity.thumb.jpg?v=1793316940ImmunityCatch measles once and you will almost certainly never catch it again. Your body has not become tougher, and the virus has not become weaker. What has changed…https://exercises.lol/video-media/a_level_biology/immunity/immunity.enzh.mp4?v=1793316940-25172026-08-15yes https://exercises.lol/videos/a_level_biology/respiration2026-10-28https://exercises.lol/video-media/a_level_biology/respiration/respiration.thumb.jpg?v=1793211581RespirationAt any moment your body holds only about fifty grams of ATP. Yet over a single day you will make and spend roughly your own body weight of it. The same…https://exercises.lol/video-media/a_level_biology/respiration/respiration.enzh.mp4?v=1793211581-25882026-08-15yes https://exercises.lol/videos/a_level_biology/photosynthesis2026-10-28https://exercises.lol/video-media/a_level_biology/photosynthesis/photosynthesis.thumb.jpg?v=1793212307PhotosynthesisHere is something strange about a tree. Almost none of it came out of the ground. The wood, the leaves, the fruit — nearly all of that mass was pulled out of…https://exercises.lol/video-media/a_level_biology/photosynthesis/photosynthesis.enzh.mp4?v=1793212307-25352026-08-15yes https://exercises.lol/videos/a_level_biology/homeostasis2026-10-30https://exercises.lol/video-media/a_level_biology/homeostasis/homeostasis.thumb.jpg?v=1793325632HomeostasisLook at a day's worth of blood sugar. Three big meals go in — and the level hardly stirs. It wanders a little, then comes straight back. That is not luck, and…https://exercises.lol/video-media/a_level_biology/homeostasis/homeostasis.enzh.mp4?v=1793325632-25812026-08-15yes https://exercises.lol/videos/a_level_biology/nerves-and-muscles2026-10-31https://exercises.lol/video-media/a_level_biology/nerves-and-muscles/nerves-and-muscles.thumb.jpg?v=1793410277Nerves and MusclesTouch something hot and your hand is already moving before you feel the pain. The signal never went to your brain to ask permission. It ran into the spinal…https://exercises.lol/video-media/a_level_biology/nerves-and-muscles/nerves-and-muscles.enzh.mp4?v=1793410277-25782026-08-15yes https://exercises.lol/videos/a_level_biology/genetics2026-10-29https://exercises.lol/video-media/a_level_biology/genetics/genetics.thumb.jpg?v=1793273072GeneticsYou have twenty three pairs of chromosomes. When a gamete is made, each pair lines up independently — either way round — so the number of different gametes you…https://exercises.lol/video-media/a_level_biology/genetics/genetics.enzh.mp4?v=1793273072-25752026-08-15yes https://exercises.lol/videos/a_level_biology/variation-and-evolution2026-10-28https://exercises.lol/video-media/a_level_biology/variation-and-evolution/variation-and-evolution.thumb.jpg?v=1793193065Variation and EvolutionIn the early eighteen hundreds, almost every peppered moth in England was pale and speckled, which hid it beautifully on lichen-covered bark. Then the…https://exercises.lol/video-media/a_level_biology/variation-and-evolution/variation-and-evolution.enzh.mp4?v=1793193065-25032026-08-15yes https://exercises.lol/videos/a_level_biology/biodiversity2026-10-29https://exercises.lol/video-media/a_level_biology/biodiversity/biodiversity.thumb.jpg?v=1793236109BiodiversityAbout one point seven million species have been described and given a name. The best estimates say there are probably eight to ten million out there. So most…https://exercises.lol/video-media/a_level_biology/biodiversity/biodiversity.enzh.mp4?v=1793236109-24802026-08-15yes https://exercises.lol/videos/a_level_biology/genetic-technology2026-10-31https://exercises.lol/video-media/a_level_biology/genetic-technology/genetic-technology.thumb.jpg?v=1793410714Genetic technologyTwo cotton plants. Same field, same insects, same week. The one on the left is barely touched. The one on the right has been eaten to bare stalks. The…https://exercises.lol/video-media/a_level_biology/genetic-technology/genetic-technology.enzh.mp4?v=1793410714-25102026-08-15yes https://exercises.lol/videos/a_level_business/business-basics2026-10-29https://exercises.lol/video-media/a_level_business/business-basics/business-basics.thumb.jpg?v=1793235521Business and its EnvironmentLook at a cup of coffee. The beans inside it cost a few cents. The milk, the cup, the lid — a few cents more. Yet people happily pay three dollars for it. So…https://exercises.lol/video-media/a_level_business/business-basics/business-basics.enzh.mp4?v=1793235521-213022026-08-15yes https://exercises.lol/videos/a_level_business/human-resources2026-10-28https://exercises.lol/video-media/a_level_business/human-resources/human-resources.thumb.jpg?v=1793194896Human Resource ManagementTwo factories. Same machines, same materials, same hours. One makes twice as much as the other. The difference is not the equipment — it is the people. Labour…https://exercises.lol/video-media/a_level_business/human-resources/human-resources.enzh.mp4?v=1793194896-26272026-08-15yes https://exercises.lol/videos/a_level_business/marketing2026-10-30https://exercises.lol/video-media/a_level_business/marketing/marketing.thumb.jpg?v=1793367494MarketingTwo shops sell the same coffee at the same price. One is always busy; the other sits empty. Nothing about the product explains it. The difference is marketing…https://exercises.lol/video-media/a_level_business/marketing/marketing.enzh.mp4?v=1793367494-29142026-08-15yes https://exercises.lol/videos/a_level_business/operations2026-10-28https://exercises.lol/video-media/a_level_business/operations/operations.thumb.jpg?v=1793190527Operations ManagementA car factory takes in steel, plastic, glass, electricity and hours of work. Out the other end comes a car worth far more than everything that went into it.…https://exercises.lol/video-media/a_level_business/operations/operations.enzh.mp4?v=1793190527-24862026-08-15yes https://exercises.lol/videos/a_level_business/finance2026-10-31https://exercises.lol/video-media/a_level_business/finance/finance.thumb.jpg?v=1793408842Finance and AccountingA business can be profitable and still die. Here is how. You sell a hundred thousand pounds of goods on credit in March. The profit looks excellent. But the…https://exercises.lol/video-media/a_level_business/finance/finance.enzh.mp4?v=1793408842-29502026-08-15yes https://exercises.lol/videos/a_level_business/external-influences2026-10-31https://exercises.lol/video-media/a_level_business/external-influences/external-influences.thumb.jpg?v=1793409963External Influences and StrategyIn two thousand and eight, thousands of well-run firms went under. Their products were good. Their staff were good. Their costs were under control. What killed…https://exercises.lol/video-media/a_level_business/external-influences/external-influences.enzh.mp4?v=1793409963-24892026-08-15yes https://exercises.lol/videos/a_level_business/organisation2026-10-30https://exercises.lol/video-media/a_level_business/organisation/organisation.thumb.jpg?v=1793403133Organisation, Leadership and HRMA director says: cut costs by five percent this quarter. It passes to a senior manager, then a department head, then a supervisor, then the team. By the time…https://exercises.lol/video-media/a_level_business/organisation/organisation.enzh.mp4?v=1793403133-25162026-08-15yes https://exercises.lol/videos/a_level_business/marketing-a-level2026-10-31https://exercises.lol/video-media/a_level_business/marketing-a-level/marketing-a-level.thumb.jpg?v=1793410906Marketing (A Level)Every shop is running on numbers. How much to order. What price to charge. Which new product to try. Get those wrong, and food goes in the bin, or the shelves…https://exercises.lol/video-media/a_level_business/marketing-a-level/marketing-a-level.enzh.mp4?v=1793410906-24852026-08-15yes https://exercises.lol/videos/a_level_business/operations-management-a-level2026-10-29https://exercises.lol/video-media/a_level_business/operations-management-a-level/operations-management-a-level.thumb.jpg?v=1793298415Operations management (A Level)A company promised its new factory in a hundred and fifteen weeks. It opened thirty weeks late, at a huge cost in wages and rent. One task slipped in the…https://exercises.lol/video-media/a_level_business/operations-management-a-level/operations-management-a-level.enzh.mp4?v=1793298415-24652026-08-15yes https://exercises.lol/videos/a_level_business/finance-and-accounting-a-level2026-10-30https://exercises.lol/video-media/a_level_business/finance-and-accounting-a-level/finance-and-accounting-a-level.thumb.jpg?v=1793366536Finance and accounting (A Level)Two shops on the same street. Both sold five hundred thousand pounds of goods last year, and they look identical. But one is about to open three new branches…https://exercises.lol/video-media/a_level_business/finance-and-accounting-a-level/finance-and-accounting-a-level.enzh.mp4?v=1793366536-25752026-08-15yes https://exercises.lol/videos/a_level_chemistry/atomic-structure2026-10-31https://exercises.lol/video-media/a_level_chemistry/atomic-structure/atomic-structure.thumb.jpg?v=1793410460Atomic StructureNo one has ever seen inside an atom. It is far too small — a single atom is about a million times thinner than a human hair. And yet we know exactly how its…https://exercises.lol/video-media/a_level_chemistry/atomic-structure/atomic-structure.enzh.mp4?v=1793410460-213852026-08-15yes https://exercises.lol/videos/a_level_chemistry/moles-stoichiometry2026-10-28https://exercises.lol/video-media/a_level_chemistry/moles-stoichiometry/moles-stoichiometry.thumb.jpg?v=1793198947Atoms, Molecules & StoichiometryHere is a problem. A single teaspoon of water holds about two hundred thousand billion billion molecules. You could never count them — not in a lifetime, not…https://exercises.lol/video-media/a_level_chemistry/moles-stoichiometry/moles-stoichiometry.enzh.mp4?v=1793198947-211412026-08-15yes https://exercises.lol/videos/a_level_chemistry/chemical-bonding2026-10-28https://exercises.lol/video-media/a_level_chemistry/chemical-bonding/chemical-bonding.thumb.jpg?v=1793192485Chemical BondingTwo molecules, almost the same size. Water, and hydrogen sulfide. Sulfur sits directly below oxygen in the Periodic Table, so you would expect the two to…https://exercises.lol/video-media/a_level_chemistry/chemical-bonding/chemical-bonding.enzh.mp4?v=1793192485-29022026-08-15yes https://exercises.lol/videos/a_level_chemistry/states-of-matter2026-10-29https://exercises.lol/video-media/a_level_chemistry/states-of-matter/states-of-matter.thumb.jpg?v=1793290288States of MatterDiamond melts at three thousand five hundred and fifty degrees Celsius. Iodine melts at one hundred and fourteen. Both are made only of non-metal atoms, and in…https://exercises.lol/video-media/a_level_chemistry/states-of-matter/states-of-matter.enzh.mp4?v=1793290288-24512026-08-15yes https://exercises.lol/videos/a_level_chemistry/energetics2026-10-29https://exercises.lol/video-media/a_level_chemistry/energetics/energetics.thumb.jpg?v=1793317676Chemical EnergeticsA Bunsen burner gets hot enough to soften glass. An instant cold pack, squeezed once, drops close to freezing. Both are just chemical reactions — one in a…https://exercises.lol/video-media/a_level_chemistry/energetics/energetics.enzh.mp4?v=1793317676-25012026-08-15yes https://exercises.lol/videos/a_level_chemistry/redox2026-10-29https://exercises.lol/video-media/a_level_chemistry/redox/redox.thumb.jpg?v=1793296857Electrochemistry & RedoxTwo pieces of iron. One is quietly rusting on a fence. The other sits inside a battery, pushing electrons through your phone. They look like completely…https://exercises.lol/video-media/a_level_chemistry/redox/redox.enzh.mp4?v=1793296857-23942026-08-15yes https://exercises.lol/videos/a_level_chemistry/equilibria2026-10-30https://exercises.lol/video-media/a_level_chemistry/equilibria/equilibria.thumb.jpg?v=1793318718EquilibriaSome reversible reactions never finish. You mix the reactants, the colour changes, and then everything just stops — halfway. Leave it for a week and it looks…https://exercises.lol/video-media/a_level_chemistry/equilibria/equilibria.enzh.mp4?v=1793318718-26122026-08-15yes https://exercises.lol/videos/a_level_chemistry/reaction-kinetics2026-10-28https://exercises.lol/video-media/a_level_chemistry/reaction-kinetics/reaction-kinetics.thumb.jpg?v=1793180838Reaction kineticsIron left outside takes years to rust away. Strike a match, and almost the same chemistry — oxygen attacking a fuel — is over in less than a second. Same…https://exercises.lol/video-media/a_level_chemistry/reaction-kinetics/reaction-kinetics.enzh.mp4?v=1793180838-24322026-08-15yes https://exercises.lol/videos/a_level_chemistry/chemical-periodicity2026-10-30https://exercises.lol/video-media/a_level_chemistry/chemical-periodicity/chemical-periodicity.thumb.jpg?v=1793328477The Periodic Table: chemical periodicitySodium and argon sit in the same row of the Periodic Table, with only six elements between them. Drop sodium into cold water and it melts into a shining ball…https://exercises.lol/video-media/a_level_chemistry/chemical-periodicity/chemical-periodicity.enzh.mp4?v=1793328477-25232026-08-15yes https://exercises.lol/videos/a_level_chemistry/group-22026-10-29https://exercises.lol/video-media/a_level_chemistry/group-2/group-2.thumb.jpg?v=1793245200Group 2Before a stomach X-ray, the patient is asked to drink a thick white liquid. It is full of barium — and barium ions are poisonous. Swallow a soluble barium salt…https://exercises.lol/video-media/a_level_chemistry/group-2/group-2.enzh.mp4?v=1793245200-24812026-08-15yes https://exercises.lol/videos/a_level_chemistry/group-172026-10-28https://exercises.lol/video-media/a_level_chemistry/group-17/group-17.thumb.jpg?v=1793224808Group 17Here are three colourless solutions. They look exactly the same. One is a chloride, one is a bromide, one is an iodide — but you cannot tell which is which by…https://exercises.lol/video-media/a_level_chemistry/group-17/group-17.enzh.mp4?v=1793224808-24472026-08-15yes https://exercises.lol/videos/a_level_chemistry/nitrogen-sulfur2026-10-29https://exercises.lol/video-media/a_level_chemistry/nitrogen-sulfur/nitrogen-sulfur.thumb.jpg?v=1793315569Nitrogen and sulfurTake a breath. Nearly four fifths of what just went into your lungs was nitrogen — and it came straight back out again, completely unchanged. Nitrogen is…https://exercises.lol/video-media/a_level_chemistry/nitrogen-sulfur/nitrogen-sulfur.enzh.mp4?v=1793315569-24602026-08-15yes https://exercises.lol/videos/a_level_chemistry/organic-intro2026-10-27https://exercises.lol/video-media/a_level_chemistry/organic-intro/organic-intro.thumb.jpg?v=1793135586An introduction to AS Level organic chemistryChemists have found more than ten million hydrocarbons and carbon compounds. Ten million. So how can anyone learn organic chemistry? Because almost all of them…https://exercises.lol/video-media/a_level_chemistry/organic-intro/organic-intro.enzh.mp4?v=1793135586-25352026-08-15yes https://exercises.lol/videos/a_level_chemistry/hydrocarbons2026-10-30https://exercises.lol/video-media/a_level_chemistry/hydrocarbons/hydrocarbons.thumb.jpg?v=1793319702HydrocarbonsTwo clear liquids, both nothing but carbon and hydrogen. And two test tubes of orange bromine water. Shake the first liquid into one tube, the second into the…https://exercises.lol/video-media/a_level_chemistry/hydrocarbons/hydrocarbons.enzh.mp4?v=1793319702-25932026-08-15yes https://exercises.lol/videos/a_level_chemistry/halogen-compounds2026-10-29https://exercises.lol/video-media/a_level_chemistry/halogen-compounds/halogen-compounds.thumb.jpg?v=1793298587Halogen compoundsPress the button on a can of freezer spray, and your skin goes numb with cold. Inside is a halogenoalkane: an alkane with a halogen atom in place of one…https://exercises.lol/video-media/a_level_chemistry/halogen-compounds/halogen-compounds.enzh.mp4?v=1793298587-24512026-08-15yes https://exercises.lol/videos/a_level_chemistry/hydroxy-compounds2026-10-29https://exercises.lol/video-media/a_level_chemistry/hydroxy-compounds/hydroxy-compounds.thumb.jpg?v=1793297800Hydroxy compoundsSqueeze hand sanitiser onto your hands. It feels cold, and then it is gone. That is ethanol — the alcohol that kills the microbes. Ethanol is only a short…https://exercises.lol/video-media/a_level_chemistry/hydroxy-compounds/hydroxy-compounds.enzh.mp4?v=1793297800-24992026-08-15yes https://exercises.lol/videos/a_level_chemistry/carbonyl-compounds2026-10-28https://exercises.lol/video-media/a_level_chemistry/carbonyl-compounds/carbonyl-compounds.thumb.jpg?v=1793164279Carbonyl compoundsOpen a bottle of nail polish remover, and that sharp smell is propanone. Your own body makes a little of it every day. All of that comes from one small group…https://exercises.lol/video-media/a_level_chemistry/carbonyl-compounds/carbonyl-compounds.enzh.mp4?v=1793164279-24822026-08-15yes https://exercises.lol/videos/a_level_chemistry/carboxylic-acids2026-10-28https://exercises.lol/video-media/a_level_chemistry/carboxylic-acids/carboxylic-acids.thumb.jpg?v=1793222715Carboxylic acids and derivativesOpen a bottle of vinegar and you know it at once. That sharp smell is ethanoic acid, and vinegar is only a weak solution of it in water. Pour a little onto…https://exercises.lol/video-media/a_level_chemistry/carboxylic-acids/carboxylic-acids.enzh.mp4?v=1793222715-24822026-08-15yes https://exercises.lol/videos/a_level_chemistry/nitrogen-compounds2026-10-31https://exercises.lol/video-media/a_level_chemistry/nitrogen-compounds/nitrogen-compounds.thumb.jpg?v=1793410997Nitrogen compoundsLook at the thread in a jacket, a rope, a pair of stockings: nylon. It is built from two kinds of molecule, joined again and again — one with a nitrogen group…https://exercises.lol/video-media/a_level_chemistry/nitrogen-compounds/nitrogen-compounds.enzh.mp4?v=1793410997-24652026-08-15yes https://exercises.lol/videos/a_level_chemistry/polymerisation2026-10-30https://exercises.lol/video-media/a_level_chemistry/polymerisation/polymerisation.thumb.jpg?v=1793330688PolymerisationLook around you. A drinks cup. A shopping bag. A plastic wrapper. All three are made of the same kind of thing: one enormous molecule, a chain that is tens of…https://exercises.lol/video-media/a_level_chemistry/polymerisation/polymerisation.enzh.mp4?v=1793330688-24432026-08-15yes https://exercises.lol/videos/a_level_chemistry/organic-synthesis2026-10-28https://exercises.lol/video-media/a_level_chemistry/organic-synthesis/organic-synthesis.thumb.jpg?v=1793213243Organic synthesisLook at almost any medicine. It is a complicated molecule, and it began as something simple — often a small molecule from crude oil. No single reaction turns…https://exercises.lol/video-media/a_level_chemistry/organic-synthesis/organic-synthesis.enzh.mp4?v=1793213243-24802026-08-15yes https://exercises.lol/videos/a_level_chemistry/analytical-techniques-as2026-10-29https://exercises.lol/video-media/a_level_chemistry/analytical-techniques-as/analytical-techniques-as.thumb.jpg?v=1793316198Analytical techniques (AS)You have just made a new compound. It is a clear liquid in a flask, with no label, and you cannot see a single molecule. How do you prove what it is? You ask…https://exercises.lol/video-media/a_level_chemistry/analytical-techniques-as/analytical-techniques-as.enzh.mp4?v=1793316198-25242026-08-15yes https://exercises.lol/videos/a_level_chemistry/energetics-a22026-10-29https://exercises.lol/video-media/a_level_chemistry/energetics-a2/energetics-a2.thumb.jpg?v=1793312331Chemical energetics (A2)Sodium is a soft metal that burns in air. Chlorine is a choking, poisonous gas. Put them together and you get table salt. Making one mole of it gives out a…https://exercises.lol/video-media/a_level_chemistry/energetics-a2/energetics-a2.enzh.mp4?v=1793312331-24822026-08-15yes https://exercises.lol/videos/a_level_chemistry/electrochemistry-a22026-10-29https://exercises.lol/video-media/a_level_chemistry/electrochemistry-a2/electrochemistry-a2.thumb.jpg?v=1793318221Electrochemistry (A2)Two things in your pocket run on the same chemistry. A battery: a reaction that wants to happen pushes electrons through a wire. And the charger: we push those…https://exercises.lol/video-media/a_level_chemistry/electrochemistry-a2/electrochemistry-a2.enzh.mp4?v=1793318221-24732026-08-15yes https://exercises.lol/videos/a_level_chemistry/equilibria-a22026-10-28https://exercises.lol/video-media/a_level_chemistry/equilibria-a2/equilibria-a2.thumb.jpg?v=1793212823Equilibria (A2)Your blood is held at pH seven point four. Move it a few tenths either way and you are in hospital. Yet all day, acid pours in — from your food, and from your…https://exercises.lol/video-media/a_level_chemistry/equilibria-a2/equilibria-a2.enzh.mp4?v=1793212823-24752026-08-15yes https://exercises.lol/videos/a_level_chemistry/kinetics-a22026-10-30https://exercises.lol/video-media/a_level_chemistry/kinetics-a2/kinetics-a2.thumb.jpg?v=1793366146Reaction kinetics (A2)Here is a real reaction: hydrogen peroxide reacting with iodide ions in acid. Look at the balanced equation. It uses two iodide ions and two hydrogen ions…https://exercises.lol/video-media/a_level_chemistry/kinetics-a2/kinetics-a2.enzh.mp4?v=1793366146-24802026-08-15yes https://exercises.lol/videos/a_level_chemistry/group-2-a22026-10-28https://exercises.lol/video-media/a_level_chemistry/group-2-a2/group-2-a2.thumb.jpg?v=1793230350Group 2 (A2)Here is a puzzle. Go down Group 2, from magnesium to barium, and the hydroxides get more soluble. Go down the same group, and the sulfates get less soluble.…https://exercises.lol/video-media/a_level_chemistry/group-2-a2/group-2-a2.enzh.mp4?v=1793230350-24852026-08-15yes https://exercises.lol/videos/a_level_chemistry/transition-elements2026-10-29https://exercises.lol/video-media/a_level_chemistry/transition-elements/transition-elements.thumb.jpg?v=1793236663Chemistry of transition elementsLook at these six test tubes: pink, orange, yellow, green, blue, violet. Every one holds a d-block metal in water, and every metal comes from the same short…https://exercises.lol/video-media/a_level_chemistry/transition-elements/transition-elements.enzh.mp4?v=1793236663-25042026-08-15yes https://exercises.lol/videos/a_level_chemistry/organic-intro-a22026-10-29https://exercises.lol/video-media/a_level_chemistry/organic-intro-a2/organic-intro-a2.thumb.jpg?v=1793315562An introduction to A Level organic chemistryTwo molecules. Same atoms, same bonds. The only difference: one is the mirror image of the other, like your left hand and your right hand. And yet one of them…https://exercises.lol/video-media/a_level_chemistry/organic-intro-a2/organic-intro-a2.enzh.mp4?v=1793315562-25082026-08-15yes https://exercises.lol/videos/a_level_chemistry/arenes2026-10-30https://exercises.lol/video-media/a_level_chemistry/arenes/arenes.thumb.jpg?v=1793331384Hydrocarbons (A2): arenesOrange bromine water is the classic test for a double bond. Shake it with an alkene, and the orange colour vanishes at once. Now shake the very same bromine…https://exercises.lol/video-media/a_level_chemistry/arenes/arenes.enzh.mp4?v=1793331384-24622026-08-15yes https://exercises.lol/videos/a_level_chemistry/halogen-a22026-10-29https://exercises.lol/video-media/a_level_chemistry/halogen-a2/halogen-a2.thumb.jpg?v=1793298357Halogen compounds (A2)A farmer sprays a field. Many of the pesticides and weedkillers in that tank are halogenoarenes: a chlorine atom bonded straight onto a benzene ring. Now look…https://exercises.lol/video-media/a_level_chemistry/halogen-a2/halogen-a2.enzh.mp4?v=1793298357-24762026-08-15yes https://exercises.lol/videos/a_level_chemistry/phenol2026-10-30https://exercises.lol/video-media/a_level_chemistry/phenol/phenol.thumb.jpg?v=1793331802Hydroxy compounds (A2): phenolIn the eighteen sixties, surgery was terrifying. The cutting could be survived; the infection that followed often could not. After an amputation, almost half…https://exercises.lol/video-media/a_level_chemistry/phenol/phenol.enzh.mp4?v=1793331802-25182026-08-15yes https://exercises.lol/videos/a_level_chemistry/carboxylic-a22026-10-29https://exercises.lol/video-media/a_level_chemistry/carboxylic-a2/carboxylic-a2.thumb.jpg?v=1793317824Carboxylic acids and derivatives (A2)Open a medicine cabinet and pick up a packet of aspirin. That tablet is an ester. At AS you met one small group: the carboxyl group. At A2 it becomes three new…https://exercises.lol/video-media/a_level_chemistry/carboxylic-a2/carboxylic-a2.enzh.mp4?v=1793317824-24872026-08-15yes https://exercises.lol/videos/a_level_chemistry/nitrogen-organic2026-10-29https://exercises.lol/video-media/a_level_chemistry/nitrogen-organic/nitrogen-organic.thumb.jpg?v=1793317044Nitrogen compoundsLook at three very different things. A sweet, dyed bright orange. A painkiller tablet. And the protein in your muscles. They share almost nothing — except one…https://exercises.lol/video-media/a_level_chemistry/nitrogen-organic/nitrogen-organic.enzh.mp4?v=1793317044-24692026-08-15yes https://exercises.lol/videos/a_level_chemistry/polymerisation-a22026-10-29https://exercises.lol/video-media/a_level_chemistry/polymerisation-a2/polymerisation-a2.thumb.jpg?v=1793316953Polymerisation (A2)Look at three very different things. A nylon rope. A plastic drinks bottle. The protein in your own hair. They seem to have nothing in common. Yet all three…https://exercises.lol/video-media/a_level_chemistry/polymerisation-a2/polymerisation-a2.enzh.mp4?v=1793316953-24782026-08-15yes https://exercises.lol/videos/a_level_chemistry/synthesis-a22026-10-29https://exercises.lol/video-media/a_level_chemistry/synthesis-a2/synthesis-a2.thumb.jpg?v=1793299462Organic synthesis (A2)Three very different things: a bright orange dye, a painkiller, and a tough plastic. All three begin as the same colourless liquid — benzene. But no single…https://exercises.lol/video-media/a_level_chemistry/synthesis-a2/synthesis-a2.enzh.mp4?v=1793299462-24722026-08-15yes https://exercises.lol/videos/a_level_chemistry/nmr-spectroscopy2026-10-30https://exercises.lol/video-media/a_level_chemistry/nmr-spectroscopy/nmr-spectroscopy.thumb.jpg?v=1793328954Analytical techniques (A2): NMRHere are seven different molecules. Every one has five carbons, ten hydrogens and one oxygen, and every one contains a carbonyl group. Weigh them in a mass…https://exercises.lol/video-media/a_level_chemistry/nmr-spectroscopy/nmr-spectroscopy.enzh.mp4?v=1793328954-24862026-08-15yes https://exercises.lol/videos/a_level_computer_science/number-systems2026-10-31https://exercises.lol/video-media/a_level_computer_science/number-systems/number-systems.thumb.jpg?v=1793408579Number Systems & DataThis photo. This song. This very video. Your name, your messages, every file on every device — inside the computer, all of it is nothing but ones and zeros.…https://exercises.lol/video-media/a_level_computer_science/number-systems/number-systems.enzh.mp4?v=1793408579-213502026-08-15yes https://exercises.lol/videos/a_level_computer_science/networks2026-10-28https://exercises.lol/video-media/a_level_computer_science/networks/networks.thumb.jpg?v=1793192208NetworksYou tap send. In less than a second, your message leaps out of your phone, races across your city, dives under an ocean through a cable, and surfaces on…https://exercises.lol/video-media/a_level_computer_science/networks/networks.enzh.mp4?v=1793192208-214282026-08-15yes https://exercises.lol/videos/a_level_computer_science/computer-components2026-10-31https://exercises.lol/video-media/a_level_computer_science/computer-components/computer-components.thumb.jpg?v=1793408882Computers & ComponentsOpen up any computer — past the case, past the chips, all the way down to the silicon — and you find switches. Not thousands. Billions. And each one does…https://exercises.lol/video-media/a_level_computer_science/computer-components/computer-components.enzh.mp4?v=1793408882-213562026-08-15yes https://exercises.lol/videos/a_level_computer_science/von-neumann2026-10-31https://exercises.lol/video-media/a_level_computer_science/von-neumann/von-neumann.thumb.jpg?v=1793411770Von Neumann ArchitectureFor most of history, a machine did one job. A loom wove cloth. A calculator added. To make it do something new, you rebuilt it. Then came a deceptively simple…https://exercises.lol/video-media/a_level_computer_science/von-neumann/von-neumann.enzh.mp4?v=1793411770-212852026-08-15yes https://exercises.lol/videos/a_level_computer_science/operating-systems2026-10-29https://exercises.lol/video-media/a_level_computer_science/operating-systems/operating-systems.thumb.jpg?v=1793312959Operating SystemsYou have never seen it, and you never will — yet it is always there. Behind every app you open, every file you save, every tap on the screen, an invisible…https://exercises.lol/video-media/a_level_computer_science/operating-systems/operating-systems.enzh.mp4?v=1793312959-212462026-08-15yes https://exercises.lol/videos/a_level_computer_science/security2026-10-29https://exercises.lol/video-media/a_level_computer_science/security/security.thumb.jpg?v=1793308110Security, Privacy & IntegrityRight now, this very second, your devices are under attack. Not by a person hunched over a keyboard — by armies of automated bots, endlessly scanning the…https://exercises.lol/video-media/a_level_computer_science/security/security.enzh.mp4?v=1793308110-29882026-08-15yes https://exercises.lol/videos/a_level_computer_science/ethics2026-10-28https://exercises.lol/video-media/a_level_computer_science/ethics/ethics.thumb.jpg?v=1793186926Ethics, Copyright & LicensingImagine you build an A I tool that sorts job applications ten times faster. Your manager is delighted. But you notice something troubling: it quietly rejects…https://exercises.lol/video-media/a_level_computer_science/ethics/ethics.enzh.mp4?v=1793186926-28502026-08-15yes https://exercises.lol/videos/a_level_computer_science/databases2026-10-30https://exercises.lol/video-media/a_level_computer_science/databases/databases.thumb.jpg?v=1793322343Databases & the Relational ModelBefore databases, each program kept its own flat files — one file per program. Picture a shop. The sales program, the billing program, and the shipping program…https://exercises.lol/video-media/a_level_computer_science/databases/databases.enzh.mp4?v=1793322343-210362026-08-15yes https://exercises.lol/videos/a_level_computer_science/computational-thinking2026-10-29https://exercises.lol/video-media/a_level_computer_science/computational-thinking/computational-thinking.thumb.jpg?v=1793308341Computational ThinkingHere is a task: build a system to run a whole shop's stock — every product, every sale, every delivery, every report. As one giant problem, it is too big to…https://exercises.lol/video-media/a_level_computer_science/computational-thinking/computational-thinking.enzh.mp4?v=1793308341-28702026-08-15yes https://exercises.lol/videos/a_level_computer_science/data-types2026-10-30https://exercises.lol/video-media/a_level_computer_science/data-types/data-types.thumb.jpg?v=1793330286Data Types & StructuresEvery value your program stores needs a data type — and picking the right one matters. Say you store whether an item is in stock. You could write the word yes…https://exercises.lol/video-media/a_level_computer_science/data-types/data-types.enzh.mp4?v=1793330286-210492026-08-15yes https://exercises.lol/videos/a_level_computer_science/programming-basics2026-10-28https://exercises.lol/video-media/a_level_computer_science/programming-basics/programming-basics.thumb.jpg?v=1793208029Programming BasicsA program must ask for a password, and keep asking until it is right. Simple — but which loop do you use? Programs make decisions and repeat work, and choosing…https://exercises.lol/video-media/a_level_computer_science/programming-basics/programming-basics.enzh.mp4?v=1793208029-214122026-08-15yes https://exercises.lol/videos/a_level_computer_science/development-cycle2026-10-30https://exercises.lol/video-media/a_level_computer_science/development-cycle/development-cycle.thumb.jpg?v=1793367410The Program Development Life CycleA tiny bug, if it slips through to release, can cost a fortune to fix — far more than catching it early. That is why we don't just start typing code. We follow…https://exercises.lol/video-media/a_level_computer_science/development-cycle/development-cycle.enzh.mp4?v=1793367410-211552026-08-15yes https://exercises.lol/videos/a_level_computer_science/user-defined-types2026-10-29https://exercises.lol/video-media/a_level_computer_science/user-defined-types/user-defined-types.thumb.jpg?v=1793305595User-Defined Data TypesA plain string field will happily store nonsense. Ask for a vehicle type, and someone types Bananas — the program accepts it without a murmur. But if you…https://exercises.lol/video-media/a_level_computer_science/user-defined-types/user-defined-types.enzh.mp4?v=1793305595-29052026-08-15yes https://exercises.lol/videos/a_level_computer_science/protocols2026-10-28https://exercises.lol/video-media/a_level_computer_science/protocols/protocols.thumb.jpg?v=1793196689Why Protocols Are NeededTwo computers want to talk, but one sends its data one way and the other expects it completely differently. The result is gibberish — like two people speaking…https://exercises.lol/video-media/a_level_computer_science/protocols/protocols.enzh.mp4?v=1793196689-26712026-08-15yes https://exercises.lol/videos/a_level_computer_science/risc-cisc2026-10-30https://exercises.lol/video-media/a_level_computer_science/risc-cisc/risc-cisc.thumb.jpg?v=1793328495RISC, Pipelines & LogicTwo chip designers face the same problem: make programs run fast. One says — build powerful instructions, so each one does a lot of work. The other says — keep…https://exercises.lol/video-media/a_level_computer_science/risc-cisc/risc-cisc.enzh.mp4?v=1793328495-28952026-08-15yes https://exercises.lol/videos/a_level_computer_science/os-resources2026-10-31https://exercises.lol/video-media/a_level_computer_science/os-resources/os-resources.thumb.jpg?v=1793407979Resources, Compilers & RPNOpen a browser, a music player, and a game. You have one processor — maybe a few cores — yet all of them seem to run at once. And together they want more…https://exercises.lol/video-media/a_level_computer_science/os-resources/os-resources.enzh.mp4?v=1793407979-28412026-08-15yes https://exercises.lol/videos/a_level_computer_science/encryption2026-10-29https://exercises.lol/video-media/a_level_computer_science/encryption/encryption.thumb.jpg?v=1793311577How Encryption WorksLook at the padlock in your browser's address bar. You typed your bank's name, and somehow your laptop is now certain it is really talking to the bank — and…https://exercises.lol/video-media/a_level_computer_science/encryption/encryption.enzh.mp4?v=1793311577-27962026-08-15yes https://exercises.lol/videos/a_level_computer_science/artificial-intelligence2026-10-31https://exercises.lol/video-media/a_level_computer_science/artificial-intelligence/artificial-intelligence.thumb.jpg?v=1793410357What AI IsNobody ever wrote the rules for telling a cat from a dog. No programmer sat down and typed "if it has pointed ears and whiskers". And yet your phone does it…https://exercises.lol/video-media/a_level_computer_science/artificial-intelligence/artificial-intelligence.enzh.mp4?v=1793410357-27912026-08-15yes https://exercises.lol/videos/a_level_computer_science/searching-sorting2026-10-30https://exercises.lol/video-media/a_level_computer_science/searching-sorting/searching-sorting.thumb.jpg?v=1793331773Searching & SortingA phone book with a million names. If you check them one at a time, you might make a million comparisons. But you already know the trick: open it in the…https://exercises.lol/video-media/a_level_computer_science/searching-sorting/searching-sorting.enzh.mp4?v=1793331773-29322026-08-15yes https://exercises.lol/videos/a_level_computer_science/paradigms2026-10-29https://exercises.lol/video-media/a_level_computer_science/paradigms/paradigms.thumb.jpg?v=1793233829Programming ParadigmsHere is one job: list every student with an A grade. One programmer writes a loop — start at the first record, check the grade, add the name to a list, move…https://exercises.lol/video-media/a_level_computer_science/paradigms/paradigms.enzh.mp4?v=1793233829-28322026-08-15yes https://exercises.lol/videos/a_level_economics/basic-economic-ideas2026-10-30https://exercises.lol/video-media/a_level_economics/basic-economic-ideas/basic-economic-ideas.thumb.jpg?v=1793324267Basic Economic IdeasWrite down everything you want. A phone, a bigger home, travel, a good education. The list never ends. Now look at what the world has: a fixed amount of land…https://exercises.lol/video-media/a_level_economics/basic-economic-ideas/basic-economic-ideas.enzh.mp4?v=1793324267-211182026-08-15yes https://exercises.lol/videos/a_level_economics/economic-problem2026-10-29https://exercises.lol/video-media/a_level_economics/economic-problem/economic-problem.thumb.jpg?v=1793302375The Fundamental Economic ProblemThink of everything you want. A better phone. More free time. Now think of what the world actually has: a fixed amount of land, a fixed number of workers, and…https://exercises.lol/video-media/a_level_economics/economic-problem/economic-problem.enzh.mp4?v=1793302375-212002026-08-15yes https://exercises.lol/videos/a_level_economics/price-system-and-the2026-10-30https://exercises.lol/video-media/a_level_economics/price-system-and-the/price-system-and-the.thumb.jpg?v=1793354368The price system and the microeconomyNobody in this market is in charge. No official decides what a kilo of tomatoes should cost. Yet every stall has a price, and by evening almost everything is…https://exercises.lol/video-media/a_level_economics/price-system-and-the/price-system-and-the.enzh.mp4?v=1793354368-29702026-08-15yes https://exercises.lol/videos/a_level_economics/government-microeconomic-intervention2026-10-30https://exercises.lol/video-media/a_level_economics/government-microeconomic-intervention/government-microeconomic-intervention.thumb.jpg?v=1793338912Government microeconomic interventionThis power station makes electricity, and you pay for the electricity. But the people living beside it breathe the smoke, and they never agreed to anything.…https://exercises.lol/video-media/a_level_economics/government-microeconomic-intervention/government-microeconomic-intervention.enzh.mp4?v=1793338912-28942026-08-15yes https://exercises.lol/videos/a_level_economics/macroeconomy2026-10-31https://exercises.lol/video-media/a_level_economics/macroeconomy/macroeconomy.thumb.jpg?v=1793407871The macroeconomyA city at night: every light is somebody working, building, selling. A shelf of food: every price tag changed this year. An economy is too big to see, so we…https://exercises.lol/video-media/a_level_economics/macroeconomy/macroeconomy.enzh.mp4?v=1793407871-210312026-08-15yes https://exercises.lol/videos/a_level_economics/government-macroeconomic-intervention2026-10-28https://exercises.lol/video-media/a_level_economics/government-macroeconomic-intervention/government-macroeconomic-intervention.thumb.jpg?v=1793212889Government macroeconomic interventionPrices are rising fast. Jobs are hard to find. Growth has stopped. Who fixes that? Two buildings decide. In one, the government chooses what to spend and what…https://exercises.lol/video-media/a_level_economics/government-macroeconomic-intervention/government-macroeconomic-intervention.enzh.mp4?v=1793212889-25332026-08-15yes https://exercises.lol/videos/a_level_economics/international-economic-issues2026-10-29https://exercises.lol/video-media/a_level_economics/international-economic-issues/international-economic-issues.thumb.jpg?v=1793307483International economic issuesLook at the label on your phone, your shoes, your desk lamp. Almost none of it was made in the country where you are sitting. It arrived in steel boxes, on…https://exercises.lol/video-media/a_level_economics/international-economic-issues/international-economic-issues.enzh.mp4?v=1793307483-25462026-08-15yes https://exercises.lol/videos/a_level_economics/price-system-and-the-microeconomy-72026-10-29https://exercises.lol/video-media/a_level_economics/price-system-and-the-microeconomy-7/price-system-and-the-microeconomy-7.thumb.jpg?v=1793301598The price system and the microeconomy (A Level)Look at these shoppers. Each has a limited budget, and every extra thing they buy gives a little less pleasure than the last. Now a huge steel plant: it makes…https://exercises.lol/video-media/a_level_economics/price-system-and-the-microeconomy-7/price-system-and-the-microeconomy-7.enzh.mp4?v=1793301598-211252026-08-15yes https://exercises.lol/videos/a_level_economics/government-microeconomic-intervention-a2026-10-29https://exercises.lol/video-media/a_level_economics/government-microeconomic-intervention-a/government-microeconomic-intervention-a.thumb.jpg?v=1793306576Government microeconomic intervention (A Level)Three ordinary pictures. Cigarettes, sold cheaply to anyone who wants them. A hillside of tin roofs, looking down on a rich city district. A factory floor…https://exercises.lol/video-media/a_level_economics/government-microeconomic-intervention-a/government-microeconomic-intervention-a.enzh.mp4?v=1793306576-24992026-08-15yes https://exercises.lol/videos/a_level_economics/macroeconomy-a-level2026-10-30https://exercises.lol/video-media/a_level_economics/macroeconomy-a-level/macroeconomy-a-level.thumb.jpg?v=1793366340The macroeconomy (A Level)Look at one building going up. Someone is paying for steel, for concrete, for wages. But the story does not stop there. The builders take those wages home and…https://exercises.lol/video-media/a_level_economics/macroeconomy-a-level/macroeconomy-a-level.enzh.mp4?v=1793366340-25132026-08-15yes https://exercises.lol/videos/a_level_economics/government-macroeconomic-intervention-a2026-10-30https://exercises.lol/video-media/a_level_economics/government-macroeconomic-intervention-a/government-macroeconomic-intervention-a.thumb.jpg?v=1793348748Government macroeconomic intervention (A Level)Inside a building like this one, a small committee meets and changes a single number: the interest rate. Nothing is built. Nothing is bought. Yet within days…https://exercises.lol/video-media/a_level_economics/government-macroeconomic-intervention-a/government-macroeconomic-intervention-a.enzh.mp4?v=1793348748-24332026-08-15yes https://exercises.lol/videos/a_level_economics/international-economic-issues-a2026-10-29https://exercises.lol/video-media/a_level_economics/international-economic-issues-a/international-economic-issues-a.thumb.jpg?v=1793256160International economic issues (A Level)A country's money loses a fifth of its value overnight. Exports are suddenly cheap, imports suddenly dear, so the trade gap should close at once. It does not.…https://exercises.lol/video-media/a_level_economics/international-economic-issues-a/international-economic-issues-a.enzh.mp4?v=1793256160-25372026-08-15yes https://exercises.lol/videos/a_level_further_mathematics/further-pure-12026-10-28https://exercises.lol/video-media/a_level_further_mathematics/further-pure-1/further-pure-1.thumb.jpg?v=1793192630Further Pure Mathematics 1Here is a cubic equation, crossing the axis at three roots. Finding those roots exactly can be hard — or even impossible by hand. But here is a beautiful…https://exercises.lol/video-media/a_level_further_mathematics/further-pure-1/further-pure-1.enzh.mp4?v=1793192630-28682026-08-15yes https://exercises.lol/videos/a_level_further_mathematics/further-pure-22026-10-29https://exercises.lol/video-media/a_level_further_mathematics/further-pure-2/further-pure-2.thumb.jpg?v=1793284310Further Pure Mathematics 2Look at any hanging chain, any power line, any suspension cable. It always settles into one special curve. You might guess a parabola — but it is not. It is…https://exercises.lol/video-media/a_level_further_mathematics/further-pure-2/further-pure-2.enzh.mp4?v=1793284310-26892026-08-15yes https://exercises.lol/videos/a_level_further_mathematics/further-mechanics2026-10-29https://exercises.lol/video-media/a_level_further_mathematics/further-mechanics/further-mechanics.thumb.jpg?v=1793315150Further MechanicsThrow a ball, fire a jet of water, launch anything into the air — and it traces the same elegant curve: a parabola. The secret is to split the motion in two.…https://exercises.lol/video-media/a_level_further_mathematics/further-mechanics/further-mechanics.enzh.mp4?v=1793315150-24842026-08-15yes https://exercises.lol/videos/a_level_further_mathematics/further-prob-stats2026-10-29https://exercises.lol/video-media/a_level_further_mathematics/further-prob-stats/further-prob-stats.thumb.jpg?v=1793300397Further Probability & StatisticsDublin, nineteen-oh-eight. Inside the Guinness brewery, a young chemist named William Gosset faces a very practical problem. He can test only a few batches of…https://exercises.lol/video-media/a_level_further_mathematics/further-prob-stats/further-prob-stats.enzh.mp4?v=1793300397-24882026-08-15yes https://exercises.lol/videos/a_level_mathematics/pure-maths-12026-10-30https://exercises.lol/video-media/a_level_mathematics/pure-maths-1/pure-maths-1.thumb.jpg?v=1793330634Pure Mathematics 1Look at a great suspension bridge. Its huge cable is not a random shape — it hangs in a perfect parabola, a curve you can write with a single equation. The…https://exercises.lol/video-media/a_level_mathematics/pure-maths-1/pure-maths-1.enzh.mp4?v=1793330634-217212026-08-15yes https://exercises.lol/videos/a_level_mathematics/pure-maths-22026-10-30https://exercises.lol/video-media/a_level_mathematics/pure-maths-2/pure-maths-2.thumb.jpg?v=1793367979Pure Mathematics 2In two thousand eleven, an earthquake off Japan measured nine on the Richter scale. A smaller quake might measure six. Only three points apart — yet the first…https://exercises.lol/video-media/a_level_mathematics/pure-maths-2/pure-maths-2.enzh.mp4?v=1793367979-27522026-08-15yes https://exercises.lol/videos/a_level_mathematics/pure-maths-32026-10-31https://exercises.lol/video-media/a_level_mathematics/pure-maths-3/pure-maths-3.thumb.jpg?v=1793411483Pure Mathematics 3For centuries, mathematicians hit a wall: what is the square root of minus one? No ordinary number, squared, gives a negative. They called it impossible, and…https://exercises.lol/video-media/a_level_mathematics/pure-maths-3/pure-maths-3.enzh.mp4?v=1793411483-28162026-08-15yes https://exercises.lol/videos/a_level_mathematics/mechanics2026-10-29https://exercises.lol/video-media/a_level_mathematics/mechanics/mechanics.thumb.jpg?v=1793298574MechanicsPush a shopping trolley, and it speeds up. Push harder, and it speeds up faster. Push a heavier one with the same effort, and it barely moves. All of mechanics…https://exercises.lol/video-media/a_level_mathematics/mechanics/mechanics.enzh.mp4?v=1793298574-27582026-08-15yes https://exercises.lol/videos/a_level_mathematics/prob-stats-12026-10-29https://exercises.lol/video-media/a_level_mathematics/prob-stats-1/prob-stats-1.thumb.jpg?v=1793292245Probability & Statistics 1Roll a single die, and the result is anyone's guess. But roll it thousands of times, or measure the heights of thousands of people, and something remarkable…https://exercises.lol/video-media/a_level_mathematics/prob-stats-1/prob-stats-1.enzh.mp4?v=1793292245-26972026-08-15yes https://exercises.lol/videos/a_level_mathematics/prob-stats-22026-10-28https://exercises.lol/video-media/a_level_mathematics/prob-stats-2/prob-stats-2.thumb.jpg?v=1793199343Probability & Statistics 2Cambridge, the nineteen-twenties. At a garden party, a lady says something surprising. She can taste, she claims, whether the milk was poured into the cup…https://exercises.lol/video-media/a_level_mathematics/prob-stats-2/prob-stats-2.enzh.mp4?v=1793199343-26052026-08-15yes https://exercises.lol/videos/a_level_physics/quantities-units2026-10-30https://exercises.lol/video-media/a_level_physics/quantities-units/quantities-units.thumb.jpg?v=1793326938Physical Quantities & UnitsIn 1999, a spacecraft reached Mars after a journey of ten months. It had cost over three hundred million dollars. But as it arrived, it was lost forever. The…https://exercises.lol/video-media/a_level_physics/quantities-units/quantities-units.enzh.mp4?v=1793326938-213182026-08-15yes https://exercises.lol/videos/a_level_physics/kinematics2026-10-30https://exercises.lol/video-media/a_level_physics/kinematics/kinematics.thumb.jpg?v=1793330818KinematicsIn 1971, an astronaut stood on the Moon and held out a hammer and a feather. On Earth, the feather would flutter down slowly, far behind the hammer. But the…https://exercises.lol/video-media/a_level_physics/kinematics/kinematics.enzh.mp4?v=1793330818-212322026-08-15yes https://exercises.lol/videos/a_level_physics/dynamics2026-10-30https://exercises.lol/video-media/a_level_physics/dynamics/dynamics.thumb.jpg?v=1793333378DynamicsIn the empty vacuum of space, there is nothing to push against — no ground, no air, nothing at all. And yet a rocket can still speed up. How? It throws mass…https://exercises.lol/video-media/a_level_physics/dynamics/dynamics.enzh.mp4?v=1793333378-212022026-08-15yes https://exercises.lol/videos/a_level_physics/moments-pressure2026-10-30https://exercises.lol/video-media/a_level_physics/moments-pressure/moments-pressure.thumb.jpg?v=1793329957Moments & PressureThe Leaning Tower of Pisa has tilted for over eight hundred years — yet it does not fall. Why? The whole weight of the tower acts at one point: its centre of…https://exercises.lol/video-media/a_level_physics/moments-pressure/moments-pressure.enzh.mp4?v=1793329957-210262026-08-15yes https://exercises.lol/videos/a_level_physics/work-energy2026-10-31https://exercises.lol/video-media/a_level_physics/work-energy/work-energy.thumb.jpg?v=1793410071Work & EnergyA roller coaster has no engine on its track. A chain hauls it up the very first hill — and after that, it is on its own. So how does it race through every loop…https://exercises.lol/video-media/a_level_physics/work-energy/work-energy.enzh.mp4?v=1793410071-210282026-08-15yes https://exercises.lol/videos/a_level_physics/deformation2026-10-30https://exercises.lol/video-media/a_level_physics/deformation/deformation.thumb.jpg?v=1793328098DeformationA bungee jumper steps off a bridge and falls — faster and faster, straight toward the ground. Then, at the last moment, an elastic cord snaps tight and pulls…https://exercises.lol/video-media/a_level_physics/deformation/deformation.enzh.mp4?v=1793328098-210102026-08-15yes https://exercises.lol/videos/a_level_physics/waves2026-10-28https://exercises.lol/video-media/a_level_physics/waves/waves.thumb.jpg?v=1793195371WavesYou are standing on a street corner. An ambulance races toward you, siren wailing at a high pitch — and the instant it passes, the pitch suddenly drops. The…https://exercises.lol/video-media/a_level_physics/waves/waves.enzh.mp4?v=1793195371-210052026-08-15yes https://exercises.lol/videos/a_level_physics/superposition2026-10-29https://exercises.lol/video-media/a_level_physics/superposition/superposition.thumb.jpg?v=1793294616SuperpositionPut on a pair of noise-cancelling headphones, and the roar of a plane engine fades to silence. But here is the strange part: they do not block the sound — they…https://exercises.lol/video-media/a_level_physics/superposition/superposition.enzh.mp4?v=1793294616-211882026-08-15yes https://exercises.lol/videos/a_level_physics/electric-current2026-10-30https://exercises.lol/video-media/a_level_physics/electric-current/electric-current.thumb.jpg?v=1793332554Electric CurrentFlip a switch, and the light comes on instantly. So the electrons must be racing through the wire at the speed of light — right? Wrong. Inside a copper wire…https://exercises.lol/video-media/a_level_physics/electric-current/electric-current.enzh.mp4?v=1793332554-210702026-08-15yes https://exercises.lol/videos/a_level_physics/practical-circuits2026-10-30https://exercises.lol/video-media/a_level_physics/practical-circuits/practical-circuits.thumb.jpg?v=1793333782Practical CircuitsHere is an old battery, and a voltmeter says it is still full: nine volts. Yet connect it to a bulb, and the bulb barely glows. How can a full battery be so…https://exercises.lol/video-media/a_level_physics/practical-circuits/practical-circuits.enzh.mp4?v=1793333782-212342026-08-15yes https://exercises.lol/videos/a_level_physics/nuclear-atom2026-10-30https://exercises.lol/video-media/a_level_physics/nuclear-atom/nuclear-atom.thumb.jpg?v=1793375496The Nuclear AtomOver a hundred years ago, physicists fired tiny alpha particles at a sheet of gold foil, thinner than paper. They expected the particles to sail straight…https://exercises.lol/video-media/a_level_physics/nuclear-atom/nuclear-atom.enzh.mp4?v=1793375496-211342026-08-15yes https://exercises.lol/videos/a_level_physics/circular-motion2026-10-29https://exercises.lol/video-media/a_level_physics/circular-motion/circular-motion.thumb.jpg?v=1793274124Circular MotionFill a bucket with water, swing it in a fast circle over your head — and not a drop falls out, even when it is completely upside down. Why doesn't the water…https://exercises.lol/video-media/a_level_physics/circular-motion/circular-motion.enzh.mp4?v=1793274124-27762026-08-15yes https://exercises.lol/videos/a_level_physics/gravitational-fields2026-10-30https://exercises.lol/video-media/a_level_physics/gravitational-fields/gravitational-fields.thumb.jpg?v=1793333355Gravitational FieldsAn apple falls from a tree. The Moon sails around the Earth. For thousands of years, no one saw any connection between them. Then Isaac Newton had one of the…https://exercises.lol/video-media/a_level_physics/gravitational-fields/gravitational-fields.enzh.mp4?v=1793333355-27342026-08-15yes https://exercises.lol/videos/a_level_physics/thermal-physics2026-10-28https://exercises.lol/video-media/a_level_physics/thermal-physics/thermal-physics.thumb.jpg?v=1793213708Thermal PhysicsTouch a metal spoon, then a wooden table, in the same room. The metal feels much colder. So it must be colder — right? Wrong. Bring a thermometer, and both…https://exercises.lol/video-media/a_level_physics/thermal-physics/thermal-physics.enzh.mp4?v=1793213708-27062026-08-15yes https://exercises.lol/videos/a_level_physics/ideal-gases2026-10-30https://exercises.lol/video-media/a_level_physics/ideal-gases/ideal-gases.thumb.jpg?v=1793325697Ideal GasesHold up a single glass of water. It looks simple enough. But inside it are more molecules than you could ever count. One mole of water — just eighteen grams, a…https://exercises.lol/video-media/a_level_physics/ideal-gases/ideal-gases.enzh.mp4?v=1793325697-28282026-08-15yes https://exercises.lol/videos/a_level_physics/internal-energy2026-10-30https://exercises.lol/video-media/a_level_physics/internal-energy/internal-energy.thumb.jpg?v=1793318732Internal EnergyPump up a bicycle tyre, quickly and hard, and something surprising happens: the pump gets hot. Warm enough to feel. You did not heat it with a flame. So where…https://exercises.lol/video-media/a_level_physics/internal-energy/internal-energy.enzh.mp4?v=1793318732-29262026-08-15yes https://exercises.lol/videos/a_level_physics/oscillations2026-10-28https://exercises.lol/video-media/a_level_physics/oscillations/oscillations.thumb.jpg?v=1793211219Oscillations & Simple Harmonic MotionIn 1940, a brand-new bridge opened across the Tacoma Narrows — long, elegant, and, as it turned out, dangerous. Within months, an ordinary wind set it heaving…https://exercises.lol/video-media/a_level_physics/oscillations/oscillations.enzh.mp4?v=1793211219-29122026-08-15yes https://exercises.lol/videos/a_level_physics/electric-fields2026-10-28https://exercises.lol/video-media/a_level_physics/electric-fields/electric-fields.thumb.jpg?v=1793190515Electric FieldsDeep inside a storm cloud, charge is building. Negative charge gathers at the base, positive charge on the ground below. Between them, in the empty air, an…https://exercises.lol/video-media/a_level_physics/electric-fields/electric-fields.enzh.mp4?v=1793190515-26632026-08-15yes https://exercises.lol/videos/a_level_physics/capacitance2026-10-29https://exercises.lol/video-media/a_level_physics/capacitance/capacitance.thumb.jpg?v=1793318310CapacitanceLook closely at a camera flash. Before the picture, a tiny part hums and whines for a second — you might even hear it. It is charging a capacitor, storing…https://exercises.lol/video-media/a_level_physics/capacitance/capacitance.enzh.mp4?v=1793318310-28882026-08-15yes https://exercises.lol/videos/a_level_physics/magnetic-fields2026-10-29https://exercises.lol/video-media/a_level_physics/magnetic-fields/magnetic-fields.thumb.jpg?v=1793309417Magnetic FieldsHigh above the poles, the sky comes alive — sheets of green light, rippling in the dark. This is the aurora. Its cause? Our planet is a giant magnet. Streams…https://exercises.lol/video-media/a_level_physics/magnetic-fields/magnetic-fields.enzh.mp4?v=1793309417-27972026-08-15yes https://exercises.lol/videos/a_level_physics/alternating-current2026-10-30https://exercises.lol/video-media/a_level_physics/alternating-current/alternating-current.thumb.jpg?v=1793349769Alternating CurrentThe electricity in your wall is restless. Fifty times every second — sometimes sixty — it reverses direction, surging one way, then the other. This is…https://exercises.lol/video-media/a_level_physics/alternating-current/alternating-current.enzh.mp4?v=1793349769-26782026-08-15yes https://exercises.lol/videos/a_level_physics/photons2026-10-29https://exercises.lol/video-media/a_level_physics/photons/photons.thumb.jpg?v=1793315158PhotonsHere is a puzzle that broke classical physics. Shine the brightest red lamp you can find onto a metal plate. Pour on more and more light. And yet — nothing…https://exercises.lol/video-media/a_level_physics/photons/photons.enzh.mp4?v=1793315158-29432026-08-15yes https://exercises.lol/videos/a_level_physics/mass-energy2026-10-29https://exercises.lol/video-media/a_level_physics/mass-energy/mass-energy.thumb.jpg?v=1793301737Mass-Energy EquivalenceLook up at the Sun. Every single second, it turns four million tonnes of itself — gone, vanished — into pure energy. Not burned. Converted. That lost mass…https://exercises.lol/video-media/a_level_physics/mass-energy/mass-energy.enzh.mp4?v=1793301737-27882026-08-15yes https://exercises.lol/videos/a_level_physics/ultrasound2026-10-29https://exercises.lol/video-media/a_level_physics/ultrasound/ultrasound.thumb.jpg?v=1793291425Ultrasound & Medical ImagingThe very first photograph of your life was probably taken with sound. Before you were born, a doctor pressed a small probe to your mother's skin, and out of…https://exercises.lol/video-media/a_level_physics/ultrasound/ultrasound.enzh.mp4?v=1793291425-210332026-08-15yes https://exercises.lol/videos/a_level_physics/luminosity2026-10-28https://exercises.lol/video-media/a_level_physics/luminosity/luminosity.thumb.jpg?v=1793179197Luminosity & the CosmosThat star is a hundred trillion kilometres away. You will never touch it. You will never visit it. And yet, from its faint light alone — just the light that…https://exercises.lol/video-media/a_level_physics/luminosity/luminosity.enzh.mp4?v=1793179197-27622026-08-15yes https://exercises.lol/videos/act/session4-012026-10-30https://exercises.lol/video-media/act/session4-01/session4-01.thumb.jpg?v=1793394538English: purpose, organisation and styleRelevance asks whether a detail serves the paragraph's actual purpose. In a paragraph about queue management, an arrival log can support a claim about waiting.…https://exercises.lol/video-media/act/session4-01/session4-01.enzh.mp4?v=1793394538-26682026-10-28yes https://exercises.lol/videos/act/session4-022026-10-30https://exercises.lol/video-media/act/session4-02/session4-02.thumb.jpg?v=1793394341English: conventions and punctuationConventions depend on grammar, not a preferred sound. “The group of volunteers records outcomes” uses singular group. “Recording the result, Noor checked the…https://exercises.lol/video-media/act/session4-02/session4-02.enzh.mp4?v=1793394341-26692026-10-28yes https://exercises.lol/videos/act/session4-032026-10-29https://exercises.lol/video-media/act/session4-03/session4-03.thumb.jpg?v=1793256104Mathematics: models, functions and higher mathsA complex conjugate changes the imaginary sign. The product of a plus b i times a minus b i equals a squared plus b squared, for real a and b. Thus, two plus i…https://exercises.lol/video-media/act/session4-03/session4-03.enzh.mp4?v=1793256104-22662026-10-28yes https://exercises.lol/videos/act/session4-042026-10-30https://exercises.lol/video-media/act/session4-04/session4-04.thumb.jpg?v=1793394322Reading: details, structure and integrationA detail is directly stated; an inference joins clues. “The neighbour waited without complaint” does not tell us the neighbour felt no impatience. The…https://exercises.lol/video-media/act/session4-04/session4-04.enzh.mp4?v=1793394322-25582026-10-28yes https://exercises.lol/videos/act/session4-052026-10-30https://exercises.lol/video-media/act/session4-05/session4-05.thumb.jpg?v=1793392932Optional Science: data, investigations and modelsA controlled comparison changes the proposed cause while holding alternative causes fixed. An engineering design must satisfy every stated constraint.…https://exercises.lol/video-media/act/session4-05/session4-05.enzh.mp4?v=1793392932-26302026-10-28yes https://exercises.lol/videos/act/session4-062026-10-30https://exercises.lol/video-media/act/session4-06/session4-06.thumb.jpg?v=1793394339Optional Writing: perspectives and argumentAn argument needs a position, a reason and an explained connection. A counterargument tests the position rather than acting as a token objection. Distinguish…https://exercises.lol/video-media/act/session4-06/session4-06.enzh.mp4?v=1793394339-25562026-10-28yes https://exercises.lol/videos/act/session4-072026-11-08https://exercises.lol/video-media/act/session4-07/session4-07.thumb.jpg?v=1794115566Real numbers, rational powers and complex arithmeticEuclid's Elements, written in Alexandria around 300 BC, includes the classic argument that no fraction squared gives exactly 2: root 2 is irrational. For…https://exercises.lol/video-media/act/session4-07/session4-07.enzh.mp4?v=1794115566-23152026-10-28yes https://exercises.lol/videos/act/session4-082026-10-30https://exercises.lol/video-media/act/session4-08/session4-08.thumb.jpg?v=1793394308Vectors and matrices as organised quantitative modelsA matrix uses labelled rows and columns. A quantity row, two comma three, and a price column, four comma five, transpose, give cost two times four plus three…https://exercises.lol/video-media/act/session4-08/session4-08.enzh.mp4?v=1793394308-22092026-10-28yes https://exercises.lol/videos/act/session4-092026-10-30https://exercises.lol/video-media/act/session4-09/session4-09.thumb.jpg?v=1793394313Linear, quadratic and polynomial relationshipsAn identity holds for every permitted input. Start with a x plus b equals c x plus d. Collect terms: open parenthesis a minus c close parenthesis x equals d…https://exercises.lol/video-media/act/session4-09/session4-09.enzh.mp4?v=1793394313-22382026-10-28yes https://exercises.lol/videos/act/session4-102026-11-08https://exercises.lol/video-media/act/session4-10/session4-10.thumb.jpg?v=1794115628Rational equations, radical branches and systemsIn 628 the Indian astronomer Brahmagupta wrote the Brahmasphutasiddhanta, one of the first books to give rules for calculating with zero and negative numbers.…https://exercises.lol/video-media/act/session4-10/session4-10.enzh.mp4?v=1794115628-23162026-10-28yes https://exercises.lol/videos/act/session4-112026-11-08https://exercises.lol/video-media/act/session4-11/session4-11.thumb.jpg?v=1794115662Functions, composition, transformations and inversesIn 1734 Leonhard Euler, working in St Petersburg, wrote f(x over a + c) in a paper: one of the first uses of the notation f(x) for a function. The idea he was…https://exercises.lol/video-media/act/session4-11/session4-11.enzh.mp4?v=1794115662-22972026-10-28yes https://exercises.lol/videos/act/session4-122026-10-30https://exercises.lol/video-media/act/session4-12/session4-12.thumb.jpg?v=1793394319Sequences, finite sums, exponentials and logarithmsArithmetic sequence: a sub n equals a sub 1 plus n minus 1, times d. Its sum is S sub n equals n, times a sub 1 plus a sub n, all over 2. Geometric sequence: a…https://exercises.lol/video-media/act/session4-12/session4-12.enzh.mp4?v=1793394319-22982026-10-28yes https://exercises.lol/videos/act/session4-132026-10-30https://exercises.lol/video-media/act/session4-13/session4-13.thumb.jpg?v=1793394824Trigonometric graphs, identities and general trianglesAmplitude is half the peak-to-trough distance. In y equals A sine of B x plus D, it is the absolute value of A. Radian period is 2 pi divided by the absolute…https://exercises.lol/video-media/act/session4-13/session4-13.enzh.mp4?v=1793394824-22862026-10-28yes https://exercises.lol/videos/act/session4-142026-10-30https://exercises.lol/video-media/act/session4-14/session4-14.thumb.jpg?v=1793392527Plane transformations, coordinate reasoning and proofRigid motions preserve lengths and angles. A 90-degree anticlockwise rotation sends x, y to negative y, x about the origin. Distance is d equals the square…https://exercises.lol/video-media/act/session4-14/session4-14.enzh.mp4?v=1793392527-23422026-10-28yes https://exercises.lol/videos/act/session4-152026-10-30https://exercises.lol/video-media/act/session4-15/session4-15.thumb.jpg?v=1793403664Conics, circle relationships and geometric measurementAn ellipse, x minus h squared over a squared plus y minus k squared over b squared equals 1, has centre at h comma k. The semiaxes are the square roots of the…https://exercises.lol/video-media/act/session4-15/session4-15.enzh.mp4?v=1793403664-23032026-10-28yes https://exercises.lol/videos/act/session4-162026-10-30https://exercises.lol/video-media/act/session4-16/session4-16.thumb.jpg?v=1793404032Data displays, normal distributions and associationA frequency counts repeated observations. Values one, three, seven with frequencies two, one, one represent four observations: one, one, three, seven. X bar…https://exercises.lol/video-media/act/session4-16/session4-16.enzh.mp4?v=1793404032-23202026-10-28yes https://exercises.lol/videos/act/session4-172026-10-30https://exercises.lol/video-media/act/session4-17/session4-17.thumb.jpg?v=1793396176Sampling inference, expected value and countingA margin of error is added and subtracted in percentage points. Estimate 63% with margin 4 points gives 59%–67%. It is an interval from a procedure, not a…https://exercises.lol/video-media/act/session4-17/session4-17.enzh.mp4?v=1793396176-23622026-10-28yes https://exercises.lol/videos/act/session4-182026-10-30https://exercises.lol/video-media/act/session4-18/session4-18.thumb.jpg?v=1793394295Essential skills in a multi-step practical modelA rate compares quantities with their units. Velocity equals distance divided by time, which is ninety kilometres divided by one point five hours, equaling…https://exercises.lol/video-media/act/session4-18/session4-18.enzh.mp4?v=1793394295-21892026-10-28yes https://exercises.lol/videos/act/session4-192026-10-30https://exercises.lol/video-media/act/session4-19/session4-19.thumb.jpg?v=1793404314English: purpose, focus and argumentative supportRelevance asks whether a detail serves the paragraph's actual purpose. In a paragraph about queue management, an arrival log can support a claim about waiting.…https://exercises.lol/video-media/act/session4-19/session4-19.enzh.mp4?v=1793404314-26682026-10-28yes https://exercises.lol/videos/act/session4-202026-10-30https://exercises.lol/video-media/act/session4-20/session4-20.thumb.jpg?v=1793395000English: paragraph order, cohesion and introductionsCohesion makes each reference and relationship followable. Introduce an arrangement before writing “This arrangement”. A conclusion should develop the…https://exercises.lol/video-media/act/session4-20/session4-20.enzh.mp4?v=1793395000-26802026-10-28yes https://exercises.lol/videos/act/session4-212026-10-30https://exercises.lol/video-media/act/session4-21/session4-21.thumb.jpg?v=1793392924English: precision, concision and consistent styleConcision removes repetition while preserving meaning. “Recorded the outcomes and wrote the results down” repeats the same act here. Formal register uses…https://exercises.lol/video-media/act/session4-21/session4-21.enzh.mp4?v=1793392924-26632026-10-28yes https://exercises.lol/videos/act/session4-222026-10-30https://exercises.lol/video-media/act/session4-22/session4-22.thumb.jpg?v=1793399319English: sentence formation, agreement and punctuationConventions depend on grammar, not a preferred sound. “The group of volunteers records outcomes” uses singular group. “Recording the result, Noor checked the…https://exercises.lol/video-media/act/session4-22/session4-22.enzh.mp4?v=1793399319-26692026-10-24yes https://exercises.lol/videos/act/session4-232026-10-30https://exercises.lol/video-media/act/session4-23/session4-23.thumb.jpg?v=1793394877Reading: explicit detail, inference and relationshipsA detail is directly stated; an inference joins clues. “The neighbour waited without complaint” does not tell us the neighbour felt no impatience. The…https://exercises.lol/video-media/act/session4-23/session4-23.enzh.mp4?v=1793394877-25582026-10-28yes https://exercises.lol/videos/act/session4-242026-10-30https://exercises.lol/video-media/act/session4-24/session4-24.thumb.jpg?v=1793394960Reading: contextual meaning, structure and point of viewPoint of view limits access to motives. First-person narration tells us what the narrator notices and thinks. “I could not tell” explicitly leaves the uncle's…https://exercises.lol/video-media/act/session4-24/session4-24.enzh.mp4?v=1793394960-25622026-10-28yes https://exercises.lol/videos/act/session4-252026-10-30https://exercises.lol/video-media/act/session4-25/session4-25.thumb.jpg?v=1793394858Reading: arguments, paired texts and graphic evidenceIntegration uses each source for the claim it actually supports. A retrieval-time table can test a claim about speed, but cannot establish historical value or…https://exercises.lol/video-media/act/session4-25/session4-25.enzh.mp4?v=1793394858-24202026-10-28yes https://exercises.lol/videos/act/session4-262026-10-30https://exercises.lol/video-media/act/session4-26/session4-26.thumb.jpg?v=1793394972Science: research summaries, controls and engineering testsA controlled comparison changes the proposed cause while holding alternative causes fixed. An engineering design must satisfy every stated constraint.…https://exercises.lol/video-media/act/session4-26/session4-26.enzh.mp4?v=1793394972-26302026-10-28yes https://exercises.lol/videos/act/session4-272026-10-30https://exercises.lol/video-media/act/session4-27/session4-27.thumb.jpg?v=1793395531Science: conflicting viewpoints and evidence that separates modelsDiscriminating evidence is a result the competing models predict differently. If both predict cooling with greater thickness, observing that trend cannot…https://exercises.lol/video-media/act/session4-27/session4-27.enzh.mp4?v=1793395531-26242026-10-28yes https://exercises.lol/videos/act/session4-282026-10-30https://exercises.lol/video-media/act/session4-28/session4-28.thumb.jpg?v=1793395018Science: data representation and defensible extrapolationA rate of change compares output change with the matching input interval. r equals delta T divided by delta t, which is 32 minus 28 degrees Celsius, all over 4…https://exercises.lol/video-media/act/session4-28/session4-28.enzh.mp4?v=1793395018-26302026-10-28yes https://exercises.lol/videos/ap_art_2d/elements-of-art2026-10-30https://exercises.lol/video-media/ap_art_2d/elements-of-art/elements-of-art.thumb.jpg?v=1793403119Elements of ArtLook at three famous pictures. A wave from Japan. A candle-lit room in England. A vase of sunflowers in France. Different countries, different centuries…https://exercises.lol/video-media/ap_art_2d/elements-of-art/elements-of-art.enzh.mp4?v=1793403119-24822026-08-15yes https://exercises.lol/videos/ap_art_2d/principles-of-design2026-10-30https://exercises.lol/video-media/ap_art_2d/principles-of-design/principles-of-design.thumb.jpg?v=1793330609Principles of DesignLook at this painting for three seconds. Where did your eye go first? Almost everyone looks at the same place — the two bright faces in the middle. That was…https://exercises.lol/video-media/ap_art_2d/principles-of-design/principles-of-design.enzh.mp4?v=1793330609-24402026-08-15yes https://exercises.lol/videos/ap_art_2d/2-d-media-materials2026-10-30https://exercises.lol/video-media/ap_art_2d/2-d-media-materials/2-d-media-materials.thumb.jpg?v=17933392562-D Media, Materials, and TechniquesLook closely. There is no grey ink in this drawing. Every soft shadow is made of separate lines, drawn one beside the other. Where the lines crowd together…https://exercises.lol/video-media/ap_art_2d/2-d-media-materials/2-d-media-materials.enzh.mp4?v=1793339256-24802026-08-15yes https://exercises.lol/videos/ap_art_2d/investigate-inquiry-and-the2026-10-30https://exercises.lol/video-media/ap_art_2d/investigate-inquiry-and-the/investigate-inquiry-and-the.thumb.jpg?v=1793404391Investigate: Inquiry and the Artistic ProcessTwo hundred years ago, a Japanese artist asked himself one question: how does one mountain look, seen from everywhere? The wave is enormous, filling more than…https://exercises.lol/video-media/ap_art_2d/investigate-inquiry-and-the/investigate-inquiry-and-the.enzh.mp4?v=1793404391-24462026-08-15yes https://exercises.lol/videos/ap_art_2d/make-practice-experimentation-and2026-10-31https://exercises.lol/video-media/ap_art_2d/make-practice-experimentation-and/make-practice-experimentation-and.thumb.jpg?v=1793408004Make: Practice, Experimentation, and RevisionLook at this pond. Claude Monet painted it again, and again, and again — about two hundred and fifty pictures of the same water, over thirty years. He was not…https://exercises.lol/video-media/ap_art_2d/make-practice-experimentation-and/make-practice-experimentation-and.enzh.mp4?v=1793408004-24482026-08-15yes https://exercises.lol/videos/ap_art_2d/present-communication-and-the2026-10-28https://exercises.lol/video-media/ap_art_2d/present-communication-and-the/present-communication-and-the.thumb.jpg?v=1793218944Present: Communication and the AP PortfolioYou have seen these three works before — but almost certainly not in a museum. You met them the way you are meeting them now: as pictures on a screen. Someone…https://exercises.lol/video-media/ap_art_2d/present-communication-and-the/present-communication-and-the.enzh.mp4?v=1793218944-24532026-08-15yes https://exercises.lol/videos/ap_biology/chemistry-of-life2026-10-30https://exercises.lol/video-media/ap_biology/chemistry-of-life/chemistry-of-life.thumb.jpg?v=1793318558Chemistry of LifeDrop an ice cube into a glass and it floats. That sounds ordinary, but it is strange. Almost every other solid sinks in its own liquid, because freezing packs…https://exercises.lol/video-media/ap_biology/chemistry-of-life/chemistry-of-life.enzh.mp4?v=1793318558-25642026-08-15yes https://exercises.lol/videos/ap_biology/cell-structure-and-function2026-10-30https://exercises.lol/video-media/ap_biology/cell-structure-and-function/cell-structure-and-function.thumb.jpg?v=1793367305Cell Structure and FunctionLook at a leaf under a microscope. You see rows of green boxes, and each box is packed with tiny green discs. Now look at a thin slice of onion. Neat brick…https://exercises.lol/video-media/ap_biology/cell-structure-and-function/cell-structure-and-function.enzh.mp4?v=1793367305-25872026-08-15yes https://exercises.lol/videos/ap_biology/cellular-energetics2026-10-27https://exercises.lol/video-media/ap_biology/cellular-energetics/cellular-energetics.thumb.jpg?v=1793134850Cellular EnergeticsLook at the washing powder in your cupboard. In warm water it removes a food stain in half an hour. In a lab, the same job would need strong acid and boiling…https://exercises.lol/video-media/ap_biology/cellular-energetics/cellular-energetics.enzh.mp4?v=1793134850-25522026-08-15yes https://exercises.lol/videos/ap_biology/cell-communication-and-cell2026-10-31https://exercises.lol/video-media/ap_biology/cell-communication-and-cell/cell-communication-and-cell.thumb.jpg?v=1793409384Cell Communication and Cell CycleLook closely. These are real cells, photographed in the middle of dividing. Inside your body, millions of new cells are made every second — skin, blood, gut…https://exercises.lol/video-media/ap_biology/cell-communication-and-cell/cell-communication-and-cell.enzh.mp4?v=1793409384-24542026-08-15yes https://exercises.lol/videos/ap_biology/heredity2026-10-27https://exercises.lol/video-media/ap_biology/heredity/heredity.thumb.jpg?v=1793137067HeredityTwo snails on the same tree. Same species, same bark, same weather. But look at the shells. One is pale with thin dark bands, the other dark with wide ones.…https://exercises.lol/video-media/ap_biology/heredity/heredity.enzh.mp4?v=1793137067-24732026-08-15yes https://exercises.lol/videos/ap_biology/gene-expression-and-regulation2026-10-31https://exercises.lol/video-media/ap_biology/gene-expression-and-regulation/gene-expression-and-regulation.thumb.jpg?v=1793408823Gene Expression and RegulationThat white thread in the tube is real DNA, pulled out of ordinary cells. It looks like nothing at all. But it holds every instruction your body will ever need.…https://exercises.lol/video-media/ap_biology/gene-expression-and-regulation/gene-expression-and-regulation.enzh.mp4?v=1793408823-25202026-08-15yes https://exercises.lol/videos/ap_biology/natural-selection2026-10-30https://exercises.lol/video-media/ap_biology/natural-selection/natural-selection.thumb.jpg?v=1793318847Natural SelectionThis is a dish of bacteria. Each white disc holds a different antibiotic — a drug made to kill them. Look at the clear rings. A wide ring means the drug still…https://exercises.lol/video-media/ap_biology/natural-selection/natural-selection.enzh.mp4?v=1793318847-24902026-08-15yes https://exercises.lol/videos/ap_biology/ecology2026-10-28https://exercises.lol/video-media/ap_biology/ecology/ecology.thumb.jpg?v=1793211094EcologyThis reef holds more kinds of life in one hectare than a whole province of farmland. Every fish depends on the coral, and the coral on tiny algae inside it.…https://exercises.lol/video-media/ap_biology/ecology/ecology.enzh.mp4?v=1793211094-24722026-08-15yes https://exercises.lol/videos/ap_calculus_ab/limits-continuity2026-10-28https://exercises.lol/video-media/ap_calculus_ab/limits-continuity/limits-continuity.thumb.jpg?v=1793209558Limits & ContinuityHere is a puzzle. A car's speedometer reads sixty kilometres per hour. But what does speed mean at a single instant? Speed is distance divided by time. Yet at…https://exercises.lol/video-media/ap_calculus_ab/limits-continuity/limits-continuity.enzh.mp4?v=1793209558-29692026-08-15yes https://exercises.lol/videos/ap_calculus_ab/defining-the-derivative2026-10-29https://exercises.lol/video-media/ap_calculus_ab/defining-the-derivative/defining-the-derivative.thumb.jpg?v=1793296586Defining the DerivativePicture a car's journey as a curve. Over a whole interval, we can measure its average speed — the slope of the straight line joining two points on the curve.…https://exercises.lol/video-media/ap_calculus_ab/defining-the-derivative/defining-the-derivative.enzh.mp4?v=1793296586-24732026-08-15yes https://exercises.lol/videos/ap_calculus_ab/chain-rule2026-10-29https://exercises.lol/video-media/ap_calculus_ab/chain-rule/chain-rule.thumb.jpg?v=1793300486The Chain RuleLook closely at this function: the sine of x squared. It is really two functions, one inside the other. First, square the input. Then take the sine of the…https://exercises.lol/video-media/ap_calculus_ab/chain-rule/chain-rule.enzh.mp4?v=1793300486-24082026-08-15yes https://exercises.lol/videos/ap_calculus_ab/derivative-in-context2026-10-30https://exercises.lol/video-media/ap_calculus_ab/derivative-in-context/derivative-in-context.thumb.jpg?v=1793318661Interpreting the Derivative in ContextNow that we can compute derivatives, we use them to describe the real world. A derivative is a rate of change. How fast is a population growing? How fast is a…https://exercises.lol/video-media/ap_calculus_ab/derivative-in-context/derivative-in-context.enzh.mp4?v=1793318661-24142026-08-15yes https://exercises.lol/videos/ap_calculus_ab/mean-value-theorem2026-10-29https://exercises.lol/video-media/ap_calculus_ab/mean-value-theorem/mean-value-theorem.thumb.jpg?v=1793305673Analysing Functions: The Mean Value TheoremImagine a road trip. Over two hours, you cover one hundred and twenty kilometres — an average speed of sixty. Here is a surprising promise: at some instant…https://exercises.lol/video-media/ap_calculus_ab/mean-value-theorem/mean-value-theorem.enzh.mp4?v=1793305673-26242026-08-15yes https://exercises.lol/videos/ap_calculus_ab/accumulation-integration2026-10-29https://exercises.lol/video-media/ap_calculus_ab/accumulation-integration/accumulation-integration.thumb.jpg?v=1793299772Accumulation & IntegrationDifferentiation found rates of change. Integration runs it in reverse: given a rate, it finds the total accumulated change. Here is the key picture. Water…https://exercises.lol/video-media/ap_calculus_ab/accumulation-integration/accumulation-integration.enzh.mp4?v=1793299772-26182026-08-15yes https://exercises.lol/videos/ap_calculus_ab/differential-equations2026-10-30https://exercises.lol/video-media/ap_calculus_ab/differential-equations/differential-equations.thumb.jpg?v=1793330423Differential EquationsMany real situations are described not by a formula, but by a rate. A population grows faster when it is larger. A hot drink cools faster when it is hotter. An…https://exercises.lol/video-media/ap_calculus_ab/differential-equations/differential-equations.enzh.mp4?v=1793330423-23232026-08-15yes https://exercises.lol/videos/ap_calculus_ab/applications-of-integration2026-10-31https://exercises.lol/video-media/ap_calculus_ab/applications-of-integration/applications-of-integration.thumb.jpg?v=1793406314Applications of IntegrationWhat is the average value of a function? Not the average of a few points — the average across a whole interval. Picture the area under the curve. Now flatten…https://exercises.lol/video-media/ap_calculus_ab/applications-of-integration/applications-of-integration.enzh.mp4?v=1793406314-23632026-08-15yes https://exercises.lol/videos/ap_calculus_bc/limits-continuity2026-10-28https://exercises.lol/video-media/ap_calculus_bc/limits-continuity/limits-continuity.thumb.jpg?v=1793227221Limits & ContinuityStart with a puzzle. A car's speedometer reads sixty kilometres per hour. But what does that mean at a single instant? Speed is distance over time. Yet in one…https://exercises.lol/video-media/ap_calculus_bc/limits-continuity/limits-continuity.enzh.mp4?v=1793227221-210732026-08-15yes https://exercises.lol/videos/ap_calculus_bc/defining-the-derivative2026-10-29https://exercises.lol/video-media/ap_calculus_bc/defining-the-derivative/defining-the-derivative.thumb.jpg?v=1793309022Defining the DerivativeDraw a journey as a curve. Pick two points, join them with a straight line, and its slope gives the average rate over an interval. But we want the rate at one…https://exercises.lol/video-media/ap_calculus_bc/defining-the-derivative/defining-the-derivative.enzh.mp4?v=1793309022-24712026-08-15yes https://exercises.lol/videos/ap_calculus_bc/chain-rule2026-10-28https://exercises.lol/video-media/ap_calculus_bc/chain-rule/chain-rule.thumb.jpg?v=1793189886The Chain RuleThink of two gears joined together. Turn the first one, and it drives the second. If the second turns three times as fast as the first, and the first turns…https://exercises.lol/video-media/ap_calculus_bc/chain-rule/chain-rule.enzh.mp4?v=1793189886-24772026-08-15yes https://exercises.lol/videos/ap_calculus_bc/derivative-in-context2026-10-29https://exercises.lol/video-media/ap_calculus_bc/derivative-in-context/derivative-in-context.thumb.jpg?v=1793302547Interpreting the Derivative in ContextA tank is draining. A cup of coffee is cooling. A city is growing. Every one of those sentences hides the same phrase. The rate at which something changes. And…https://exercises.lol/video-media/ap_calculus_bc/derivative-in-context/derivative-in-context.enzh.mp4?v=1793302547-25062026-08-15yes https://exercises.lol/videos/ap_calculus_bc/mean-value-theorem2026-10-29https://exercises.lol/video-media/ap_calculus_bc/mean-value-theorem/mean-value-theorem.thumb.jpg?v=1793290321Using the Mean Value TheoremYou drive two hundred kilometres in two hours. Your average speed was one hundred kilometres per hour. Now here is a claim. At some moment during that drive…https://exercises.lol/video-media/ap_calculus_bc/mean-value-theorem/mean-value-theorem.enzh.mp4?v=1793290321-25722026-08-15yes https://exercises.lol/videos/ap_calculus_bc/accumulation-integration2026-10-28https://exercises.lol/video-media/ap_calculus_bc/accumulation-integration/accumulation-integration.thumb.jpg?v=1793182667Exploring Accumulations of ChangeWater flows into a tank. The meter shows litres per minute. That is a rate of change. Now, how much water arrived in the first ten minutes? Draw the rate…https://exercises.lol/video-media/ap_calculus_bc/accumulation-integration/accumulation-integration.enzh.mp4?v=1793182667-26012026-08-15yes https://exercises.lol/videos/ap_calculus_bc/differential-equations2026-10-29https://exercises.lol/video-media/ap_calculus_bc/differential-equations/differential-equations.thumb.jpg?v=1793306960Modeling with Differential EquationsNormally you are handed a function and asked for its slope. A differential equation turns that around. You are handed a rule for the slope at every point, and…https://exercises.lol/video-media/ap_calculus_bc/differential-equations/differential-equations.enzh.mp4?v=1793306960-25062026-08-15yes https://exercises.lol/videos/ap_calculus_bc/applications-of-integration2026-10-30https://exercises.lol/video-media/ap_calculus_bc/applications-of-integration/applications-of-integration.thumb.jpg?v=1793355353Applications of IntegrationHere is a bumpy graph, and the area underneath it. Now imagine pouring that area into a rectangle over the same interval, and letting it level off. The height…https://exercises.lol/video-media/ap_calculus_bc/applications-of-integration/applications-of-integration.enzh.mp4?v=1793355353-25982026-08-15yes https://exercises.lol/videos/ap_calculus_bc/parametric-polar-vector2026-10-29https://exercises.lol/video-media/ap_calculus_bc/parametric-polar-vector/parametric-polar-vector.thumb.jpg?v=1793308129Parametric, Vector & PolarSome curves cannot be written as y equals a function of x. Think of a particle looping around, or a path that crosses itself — for one x there would be two y…https://exercises.lol/video-media/ap_calculus_bc/parametric-polar-vector/parametric-polar-vector.enzh.mp4?v=1793308129-23642026-08-15yes https://exercises.lol/videos/ap_calculus_bc/infinite-series2026-10-28https://exercises.lol/video-media/ap_calculus_bc/infinite-series/infinite-series.thumb.jpg?v=1793189456Infinite SeriesCan you add infinitely many numbers and get a finite answer? Surprisingly, yes. Add forever, and sometimes the total runs away to infinity — but sometimes it…https://exercises.lol/video-media/ap_calculus_bc/infinite-series/infinite-series.enzh.mp4?v=1793189456-24992026-08-15yes https://exercises.lol/videos/ap_chemistry/atomic-structure2026-10-29https://exercises.lol/video-media/ap_chemistry/atomic-structure/atomic-structure.thumb.jpg?v=1793257266Atomic Structure and PropertiesA chemical equation counts particles. Two of this react with one of that. But atoms are far too small to count, and there is no instrument that will hand you a…https://exercises.lol/video-media/ap_chemistry/atomic-structure/atomic-structure.enzh.mp4?v=1793257266-25592026-08-15yes https://exercises.lol/videos/ap_chemistry/compound-structure-and-properties2026-10-28https://exercises.lol/video-media/ap_chemistry/compound-structure-and-properties/compound-structure-and-properties.thumb.jpg?v=1793206868Compound Structure and PropertiesThree solids on a bench. Table salt. A diamond. A piece of copper. Hit the salt with a hammer and it shatters. The diamond scratches almost anything. The…https://exercises.lol/video-media/ap_chemistry/compound-structure-and-properties/compound-structure-and-properties.enzh.mp4?v=1793206868-25242026-08-15yes https://exercises.lol/videos/ap_chemistry/properties-of-substances-and2026-10-30https://exercises.lol/video-media/ap_chemistry/properties-of-substances-and/properties-of-substances-and.thumb.jpg?v=1793349400Properties of Substances and MixturesBoiling water. To make steam you must reach one hundred degrees Celsius. Methane has almost the same mass, and boils at minus one hundred and sixty-two.…https://exercises.lol/video-media/ap_chemistry/properties-of-substances-and/properties-of-substances-and.enzh.mp4?v=1793349400-26542026-08-15yes https://exercises.lol/videos/ap_chemistry/chemical-reactions2026-10-30https://exercises.lol/video-media/ap_chemistry/chemical-reactions/chemical-reactions.thumb.jpg?v=1793404571Chemical ReactionsA strip of magnesium metal. Touch it with a flame and it burns — combustion — with a light too bright to look at. What is left is not magnesium any more. It is…https://exercises.lol/video-media/ap_chemistry/chemical-reactions/chemical-reactions.enzh.mp4?v=1793404571-24612026-08-15yes https://exercises.lol/videos/ap_chemistry/kinetics2026-10-28https://exercises.lol/video-media/ap_chemistry/kinetics/kinetics.thumb.jpg?v=1793214520KineticsLook inside a car's exhaust pipe. This ceramic honeycomb is a catalytic converter. The gases rushing through it are poisonous. Left alone they would take years…https://exercises.lol/video-media/ap_chemistry/kinetics/kinetics.enzh.mp4?v=1793214520-24802026-08-15yes https://exercises.lol/videos/ap_chemistry/thermochemistry2026-10-29https://exercises.lol/video-media/ap_chemistry/thermochemistry/thermochemistry.thumb.jpg?v=1793310460ThermochemistrySqueeze this pack and in seconds it turns icy cold. Nothing is burning; nothing is cooling it from outside. A solid is simply dissolving in the water inside…https://exercises.lol/video-media/ap_chemistry/thermochemistry/thermochemistry.enzh.mp4?v=1793310460-25332026-08-15yes https://exercises.lol/videos/ap_chemistry/equilibrium2026-10-28https://exercises.lol/video-media/ap_chemistry/equilibrium/equilibrium.thumb.jpg?v=1793184268EquilibriumA chemical plant at dusk. Inside it, nitrogen from the air is turned into ammonia — the fertiliser that feeds about half the people alive today. But the…https://exercises.lol/video-media/ap_chemistry/equilibrium/equilibrium.enzh.mp4?v=1793184268-25042026-08-15yes https://exercises.lol/videos/ap_chemistry/acids-and-bases2026-10-28https://exercises.lol/video-media/ap_chemistry/acids-and-bases/acids-and-bases.thumb.jpg?v=1793228605Acids and BasesTwo strips of paper — one red, one blue. Dip them in a liquid and the colour changes, and that colour tells you whether the liquid is an acid or a base.…https://exercises.lol/video-media/ap_chemistry/acids-and-bases/acids-and-bases.enzh.mp4?v=1793228605-25032026-08-15yes https://exercises.lol/videos/ap_chemistry/thermodynamics-and-electrochemistry2026-10-30https://exercises.lol/video-media/ap_chemistry/thermodynamics-and-electrochemistry/thermodynamics-and-electrochemistry.thumb.jpg?v=1793328968Thermodynamics and ElectrochemistryTwo puzzles. Hold an ice cube: it melts in your hand, even though melting takes energy in. Now look at a diamond. Every diamond should slowly turn into…https://exercises.lol/video-media/ap_chemistry/thermodynamics-and-electrochemistry/thermodynamics-and-electrochemistry.enzh.mp4?v=1793328968-24962026-08-15yes https://exercises.lol/videos/ap_computer_science_a/objects-methods2026-10-29https://exercises.lol/video-media/ap_computer_science_a/objects-methods/objects-methods.thumb.jpg?v=1793283760Using Objects and MethodsHere are two Java programs. The first is missing a semicolon. The second divides seven by two and stores the answer in a whole number. The compiler stops the…https://exercises.lol/video-media/ap_computer_science_a/objects-methods/objects-methods.enzh.mp4?v=1793283760-29052026-08-15yes https://exercises.lol/videos/ap_computer_science_a/selection-iteration2026-10-30https://exercises.lol/video-media/ap_computer_science_a/selection-iteration/selection-iteration.thumb.jpg?v=1793323815Selection and IterationHere are three loops. The first two differ by one character — a less-than instead of a less-than-or-equal. The first runs ten times. The second runs eleven.…https://exercises.lol/video-media/ap_computer_science_a/selection-iteration/selection-iteration.enzh.mp4?v=1793323815-24772026-08-15yes https://exercises.lol/videos/ap_computer_science_a/class-creation2026-10-30https://exercises.lol/video-media/ap_computer_science_a/class-creation/class-creation.thumb.jpg?v=1793322325Class CreationHere is a student, stored as three loose variables: a name, a year, and a grade. That works. Now add a thousand students. You need three thousand variables…https://exercises.lol/video-media/ap_computer_science_a/class-creation/class-creation.enzh.mp4?v=1793322325-24452026-08-15yes https://exercises.lol/videos/ap_computer_science_a/data-collections2026-10-29https://exercises.lol/video-media/ap_computer_science_a/data-collections/data-collections.thumb.jpg?v=1793312481Data CollectionsTake one photo on your phone. To the computer it is not a picture at all — it is a grid of numbers, one for every pixel, about twelve million of them. Now try…https://exercises.lol/video-media/ap_computer_science_a/data-collections/data-collections.enzh.mp4?v=1793312481-28112026-08-15yes https://exercises.lol/videos/ap_computer_science_principles/creative-development2026-10-31https://exercises.lol/video-media/ap_computer_science_principles/creative-development/creative-development.thumb.jpg?v=1793409242Creative DevelopmentHere is a program that should print the average of two numbers. It runs. It does not crash. It prints an answer — and the answer is wrong. Give it four and six…https://exercises.lol/video-media/ap_computer_science_principles/creative-development/creative-development.enzh.mp4?v=1793409242-23742026-08-15yes https://exercises.lol/videos/ap_computer_science_principles/data2026-10-28https://exercises.lol/video-media/ap_computer_science_principles/data/data.thumb.jpg?v=1793214228DataPlay a song. What reaches your ear is a wave — smooth, continuous, never jumping from one value to the next. But your phone cannot store a wave. It can only…https://exercises.lol/video-media/ap_computer_science_principles/data/data.enzh.mp4?v=1793214228-24932026-08-15yes https://exercises.lol/videos/ap_computer_science_principles/algorithms-programming2026-10-30https://exercises.lol/video-media/ap_computer_science_principles/algorithms-programming/algorithms-programming.thumb.jpg?v=1793323809Algorithms and ProgrammingImagine a phone book with a million names, and you must find one. Check them one at a time, and you could be there all day. There is a way to find it in about…https://exercises.lol/video-media/ap_computer_science_principles/algorithms-programming/algorithms-programming.enzh.mp4?v=1793323809-25502026-08-15yes https://exercises.lol/videos/ap_computer_science_principles/computer-systems-and-networks2026-10-30https://exercises.lol/video-media/ap_computer_science_principles/computer-systems-and-networks/computer-systems-and-networks.thumb.jpg?v=1793319253Computer Systems and NetworksPeople call it the cloud. It is not a cloud. This box sits in somebody's home: a router, taking data from your phone and passing it on. This plug is the other…https://exercises.lol/video-media/ap_computer_science_principles/computer-systems-and-networks/computer-systems-and-networks.enzh.mp4?v=1793319253-24662026-08-15yes https://exercises.lol/videos/ap_computer_science_principles/impact-of-computing2026-10-29https://exercises.lol/video-media/ap_computer_science_principles/impact-of-computing/impact-of-computing.thumb.jpg?v=1793316274Impact of ComputingIn nineteen eighty-nine, one scientist built a small tool so physicists could swap papers faster. He was not planning any of this. A car that drives itself. A…https://exercises.lol/video-media/ap_computer_science_principles/impact-of-computing/impact-of-computing.enzh.mp4?v=1793316274-24922026-08-15yes https://exercises.lol/videos/ap_cybersecurity/intro-security2026-10-30https://exercises.lol/video-media/ap_cybersecurity/intro-security/intro-security.thumb.jpg?v=1793328112Introduction to SecurityYou can build a perfect wall. Unbreakable encryption, a firewall on every port, patches applied the day they ship. And an adversary can still walk straight…https://exercises.lol/video-media/ap_cybersecurity/intro-security/intro-security.enzh.mp4?v=1793328112-24722026-08-15yes https://exercises.lol/videos/ap_cybersecurity/securing-spaces2026-10-30https://exercises.lol/video-media/ap_cybersecurity/securing-spaces/securing-spaces.thumb.jpg?v=1793319728Securing SpacesA padlock on a chain. A camera above a door. Not computers, not code — but security. Because an adversary who cannot break your encryption has a simpler plan…https://exercises.lol/video-media/ap_cybersecurity/securing-spaces/securing-spaces.enzh.mp4?v=1793319728-25692026-08-15yes https://exercises.lol/videos/ap_cybersecurity/securing-networks2026-10-28https://exercises.lol/video-media/ap_cybersecurity/securing-networks/securing-networks.thumb.jpg?v=1793225597Securing NetworksYou send a message to your bank. It arrives. The reply comes back. Everything looks normal. But someone is sitting quietly between you, reading every message…https://exercises.lol/video-media/ap_cybersecurity/securing-networks/securing-networks.enzh.mp4?v=1793225597-25662026-08-15yes https://exercises.lol/videos/ap_cybersecurity/securing-devices2026-10-28https://exercises.lol/video-media/ap_cybersecurity/securing-devices/securing-devices.thumb.jpg?v=1793199137Securing DevicesIt is Monday morning in a busy hospital. In under a minute, the screens in the ward, the pharmacy and the records office all change. Every file on them is…https://exercises.lol/video-media/ap_cybersecurity/securing-devices/securing-devices.enzh.mp4?v=1793199137-25722026-08-15yes https://exercises.lol/videos/ap_drawing/line-and-mark-making2026-10-29https://exercises.lol/video-media/ap_drawing/line-and-mark-making/line-and-mark-making.thumb.jpg?v=1793307053Line and Mark-MakingLook at these three drawings. No paint. No colour. Just a pencil, a pen, a needle on a metal plate. Every shadow you can see here is built out of marks: lines…https://exercises.lol/video-media/ap_drawing/line-and-mark-making/line-and-mark-making.enzh.mp4?v=1793307053-24642026-08-15yes https://exercises.lol/videos/ap_drawing/value-light-and-form2026-10-29https://exercises.lol/video-media/ap_drawing/value-light-and-form/value-light-and-form.thumb.jpg?v=1793307052Value, Light, and FormLook at this room. Almost all of it is dark. One small light is hidden behind the boy in the middle, and it is the only light in the picture. Yet you can still…https://exercises.lol/video-media/ap_drawing/value-light-and-form/value-light-and-form.enzh.mp4?v=1793307052-24582026-08-15yes https://exercises.lol/videos/ap_drawing/space-depth-and-proportion2026-10-30https://exercises.lol/video-media/ap_drawing/space-depth-and-proportion/space-depth-and-proportion.thumb.jpg?v=1793338482Space, Depth, and ProportionLook down this road. Its two edges are exactly parallel. They never meet. But in this photograph they run together and touch, far away. Your eye read depth out…https://exercises.lol/video-media/ap_drawing/space-depth-and-proportion/space-depth-and-proportion.enzh.mp4?v=1793338482-24642026-08-15yes https://exercises.lol/videos/ap_drawing/drawing-media-and-processes2026-10-28https://exercises.lol/video-media/ap_drawing/drawing-media-and-processes/drawing-media-and-processes.thumb.jpg?v=1793188686Drawing Media and ProcessesThree drawings here, and three materials. A portrait in pencil: it whispers, and it can always be rubbed out. A still life in charcoal: it shouts, it smudges…https://exercises.lol/video-media/ap_drawing/drawing-media-and-processes/drawing-media-and-processes.enzh.mp4?v=1793188686-25142026-08-15yes https://exercises.lol/videos/ap_drawing/investigate-inquiry-and-the2026-10-30https://exercises.lol/video-media/ap_drawing/investigate-inquiry-and-the/investigate-inquiry-and-the.thumb.jpg?v=1793350796Investigate: Inquiry and the Artistic ProcessThis is a page from an artist's notebook. John Singer Sargent drew on it in eighteen seventy, when he was still a teenager. Look at what is on it. Half a…https://exercises.lol/video-media/ap_drawing/investigate-inquiry-and-the/investigate-inquiry-and-the.enzh.mp4?v=1793350796-24672026-08-15yes https://exercises.lol/videos/ap_drawing/make-practice-experimentation-and2026-10-30https://exercises.lol/video-media/ap_drawing/make-practice-experimentation-and/make-practice-experimentation-and.thumb.jpg?v=1793350089Make: Practice, Experimentation, and RevisionLook at this sheet. Michelangelo drew the figure. Now look closely at the parts: an arm, a hand, a foot, a head, each studied carefully. One page, and you can…https://exercises.lol/video-media/ap_drawing/make-practice-experimentation-and/make-practice-experimentation-and.enzh.mp4?v=1793350089-24492026-08-15yes https://exercises.lol/videos/ap_drawing/present-communication-and-the2026-10-30https://exercises.lol/video-media/ap_drawing/present-communication-and-the/present-communication-and-the.thumb.jpg?v=1793322311Present: Communication and the AP Drawing PortfolioYou spend a year drawing. Then, in May, everything you made leaves the room. The reader who scores your work never meets you, and never sees your paper. They…https://exercises.lol/video-media/ap_drawing/present-communication-and-the/present-communication-and-the.enzh.mp4?v=1793322311-24562026-08-15yes https://exercises.lol/videos/ap_english_language/unit-1-claims-evidence-and-the-rhetorical-situation2026-10-30https://exercises.lol/video-media/ap_english_language/unit-1-claims-evidence-and-the-rhetorical-situation/unit-1-claims-evidence-and-the-rhetorical-situation.thumb.jpg?v=1793331254Unit 1: Claims, Evidence, and the Rhetorical SituationHere is the single most common weak answer in this whole course. "The writer uses a rhetorical question." That sentence earns nothing, and it is what most…https://exercises.lol/video-media/ap_english_language/unit-1-claims-evidence-and-the-rhetorical-situation/unit-1-claims-evidence-and-the-rhetorical-situation.enzh.mp4?v=1793331254-23802026-09-03yes https://exercises.lol/videos/ap_english_language/unit-2-audience-thesis-and-supporting-evidence2026-10-30https://exercises.lol/video-media/ap_english_language/unit-2-audience-thesis-and-supporting-evidence/unit-2-audience-thesis-and-supporting-evidence.thumb.jpg?v=1793403635Unit 2: Audience, Thesis, and Supporting EvidenceHere is a test you can run on your own drafts in about ten seconds. Read one paragraph and ask: would this read identically to a completely different audience?…https://exercises.lol/video-media/ap_english_language/unit-2-audience-thesis-and-supporting-evidence/unit-2-audience-thesis-and-supporting-evidence.enzh.mp4?v=1793403635-23542026-09-03yes https://exercises.lol/videos/ap_english_language/unit-3-line-of-reasoning-and-methods-of-development2026-10-30https://exercises.lol/video-media/ap_english_language/unit-3-line-of-reasoning-and-methods-of-development/unit-3-line-of-reasoning-and-methods-of-development.thumb.jpg?v=1793318418Unit 3: Line of Reasoning and Methods of DevelopmentUnit 3 is where the course stops being about parts and starts being about structure, and here is the test that tells you whether you have any. Take your essay…https://exercises.lol/video-media/ap_english_language/unit-3-line-of-reasoning-and-methods-of-development/unit-3-line-of-reasoning-and-methods-of-development.enzh.mp4?v=1793318418-23562026-09-03yes https://exercises.lol/videos/ap_english_language/unit-4-introductions-conclusions-and-development2026-10-28https://exercises.lol/video-media/ap_english_language/unit-4-introductions-conclusions-and-development/unit-4-introductions-conclusions-and-development.thumb.jpg?v=1793187412Unit 4: Introductions, Conclusions, and DevelopmentUnit 4 covers the two positions in a text where a writer's choices are most visible — the beginning and the end. And it comes with a warning about your own…https://exercises.lol/video-media/ap_english_language/unit-4-introductions-conclusions-and-development/unit-4-introductions-conclusions-and-development.enzh.mp4?v=1793187412-23172026-09-03yes https://exercises.lol/videos/ap_english_language/unit-5-organization-coherence-and-style2026-10-28https://exercises.lol/video-media/ap_english_language/unit-5-organization-coherence-and-style/unit-5-organization-coherence-and-style.thumb.jpg?v=1793189515Unit 5: Organization, Coherence, and StyleThe CED's statement of the body paragraph is exact and worth memorising. The body paragraphs of a written argument make claims, support them with evidence, and…https://exercises.lol/video-media/ap_english_language/unit-5-organization-coherence-and-style/unit-5-organization-coherence-and-style.enzh.mp4?v=1793189515-23412026-09-03yes https://exercises.lol/videos/ap_english_language/unit-6-evidence-thesis-and-stylistic-choices2026-10-28https://exercises.lol/video-media/ap_english_language/unit-6-evidence-thesis-and-stylistic-choices/unit-6-evidence-thesis-and-stylistic-choices.thumb.jpg?v=1793200672Unit 6: Evidence, Thesis, and Stylistic ChoicesUnit 6 is the synthesis unit, and it contains the single sharpest distinction in the course. A position and a perspective are different. Sources may hold the…https://exercises.lol/video-media/ap_english_language/unit-6-evidence-thesis-and-stylistic-choices/unit-6-evidence-thesis-and-stylistic-choices.enzh.mp4?v=1793200672-23202026-09-03yes https://exercises.lol/videos/ap_english_language/unit-7-qualifying-arguments-syntax-and-conventions2026-10-29https://exercises.lol/video-media/ap_english_language/unit-7-qualifying-arguments-syntax-and-conventions/unit-7-qualifying-arguments-syntax-and-conventions.thumb.jpg?v=1793309828Unit 7: Qualifying Arguments, Syntax, and ConventionsMost students assume a stronger-sounding claim scores better. The opposite is true, and it is easy to see why. An unqualified claim is easy to defeat with one…https://exercises.lol/video-media/ap_english_language/unit-7-qualifying-arguments-syntax-and-conventions/unit-7-qualifying-arguments-syntax-and-conventions.enzh.mp4?v=1793309828-23792026-09-03yes https://exercises.lol/videos/ap_english_language/unit-8-audience-tone-and-sentence-craft2026-10-29https://exercises.lol/video-media/ap_english_language/unit-8-audience-tone-and-sentence-craft/unit-8-audience-tone-and-sentence-craft.thumb.jpg?v=1793316271Unit 8: Audience, Tone, and Sentence CraftA writer's style is the mix of word choice, syntax and conventions employed by that writer. Style is a composite — which is why "the writer's style is formal"…https://exercises.lol/video-media/ap_english_language/unit-8-audience-tone-and-sentence-craft/unit-8-audience-tone-and-sentence-craft.enzh.mp4?v=1793316271-23442026-09-03yes https://exercises.lol/videos/ap_english_language/unit-9-refining-qualified-arguments2026-10-30https://exercises.lol/video-media/ap_english_language/unit-9-refining-qualified-arguments/unit-9-refining-qualified-arguments.thumb.jpg?v=1793320832Unit 9: Refining Qualified ArgumentsUnit 9 is short, and it is the course's final move: how to handle the arguments that oppose yours. Everything here is directly rewarded on the exam, and the…https://exercises.lol/video-media/ap_english_language/unit-9-refining-qualified-arguments/unit-9-refining-qualified-arguments.enzh.mp4?v=1793320832-22902026-09-03yes https://exercises.lol/videos/ap_english_literature/unit-1-short-fiction-i2026-10-27https://exercises.lol/video-media/ap_english_literature/unit-1-short-fiction-i/unit-1-short-fiction-i.thumb.jpg?v=1793136236Unit 1: Short Fiction IAP English Literature reads texts in three genres across nine units — short fiction, poetry, and longer fiction or drama — each visited three times at…https://exercises.lol/video-media/ap_english_literature/unit-1-short-fiction-i/unit-1-short-fiction-i.enzh.mp4?v=1793136236-24002026-09-03yes https://exercises.lol/videos/ap_english_literature/unit-2-poetry-i2026-10-28https://exercises.lol/video-media/ap_english_literature/unit-2-poetry-i/unit-2-poetry-i.thumb.jpg?v=1793182420Unit 2: Poetry IUnit 2 is the course's first poetry unit, and it adds two things to Unit 1's toolkit: structure as an object of analysis, and figurative language handled…https://exercises.lol/video-media/ap_english_literature/unit-2-poetry-i/unit-2-poetry-i.enzh.mp4?v=1793182420-23692026-09-03yes https://exercises.lol/videos/ap_english_literature/unit-3-longer-fiction-or-drama-i2026-10-29https://exercises.lol/video-media/ap_english_literature/unit-3-longer-fiction-or-drama-i/unit-3-longer-fiction-or-drama-i.thumb.jpg?v=1793309225Unit 3: Longer Fiction or Drama IUnit 3 is the first longer-fiction-or-drama unit, and the thing to notice is that the length changes what is analysable. Three things become available that a…https://exercises.lol/video-media/ap_english_literature/unit-3-longer-fiction-or-drama-i/unit-3-longer-fiction-or-drama-i.enzh.mp4?v=1793309225-25152026-09-03yes https://exercises.lol/videos/ap_english_literature/unit-4-short-fiction-ii2026-10-29https://exercises.lol/video-media/ap_english_literature/unit-4-short-fiction-ii/unit-4-short-fiction-ii.thumb.jpg?v=1793310378Unit 4: Short Fiction IIUnit 4 returns to short fiction with a much larger toolkit, and its two most valuable additions are narrative distance and the idea that choices reveal values.…https://exercises.lol/video-media/ap_english_literature/unit-4-short-fiction-ii/unit-4-short-fiction-ii.enzh.mp4?v=1793310378-26462026-09-03yes https://exercises.lol/videos/ap_english_literature/unit-5-poetry-ii2026-10-28https://exercises.lol/video-media/ap_english_literature/unit-5-poetry-ii/unit-5-poetry-ii.thumb.jpg?v=1793177403Unit 5: Poetry IIUnit 5 is the second poetry unit, and it does two things: it names the forms a poem can take, and it completes the figurative toolkit. Closed forms include…https://exercises.lol/video-media/ap_english_literature/unit-5-poetry-ii/unit-5-poetry-ii.enzh.mp4?v=1793177403-25432026-09-03yes https://exercises.lol/videos/ap_english_literature/unit-6-longer-fiction-or-drama-ii2026-10-28https://exercises.lol/video-media/ap_english_literature/unit-6-longer-fiction-or-drama-ii/unit-6-longer-fiction-or-drama-ii.thumb.jpg?v=1793213396Unit 6: Longer Fiction or Drama IIUnit 6 is the second longer-fiction-or-drama unit, and it adds the two most sophisticated tools in the course: narrator reliability and the symbol. It opens…https://exercises.lol/video-media/ap_english_literature/unit-6-longer-fiction-or-drama-ii/unit-6-longer-fiction-or-drama-ii.enzh.mp4?v=1793213396-25742026-09-03yes https://exercises.lol/videos/ap_english_literature/unit-7-short-fiction-iii2026-10-30https://exercises.lol/video-media/ap_english_literature/unit-7-short-fiction-iii/unit-7-short-fiction-iii.thumb.jpg?v=1793330572Unit 7: Short Fiction IIIUnit 7 is the last short-fiction unit, and it sharpens two things: how change happens in a character, and pacing as a deliberate manipulation of time. Take…https://exercises.lol/video-media/ap_english_literature/unit-7-short-fiction-iii/unit-7-short-fiction-iii.enzh.mp4?v=1793330572-25412026-09-03yes https://exercises.lol/videos/ap_english_literature/unit-8-poetry-iii2026-10-29https://exercises.lol/video-media/ap_english_literature/unit-8-poetry-iii/unit-8-poetry-iii.thumb.jpg?v=1793311110Unit 8: Poetry IIIUnit 8 is the last poetry unit and it handles the hardest material in the course: the family of devices built on contradiction. But it opens with the most…https://exercises.lol/video-media/ap_english_literature/unit-8-poetry-iii/unit-8-poetry-iii.enzh.mp4?v=1793311110-25202026-09-03yes https://exercises.lol/videos/ap_english_literature/unit-9-longer-fiction-or-drama-iii2026-10-28https://exercises.lol/video-media/ap_english_literature/unit-9-longer-fiction-or-drama-iii/unit-9-longer-fiction-or-drama-iii.thumb.jpg?v=1793199910Unit 9: Longer Fiction or Drama IIIUnit 9 is the final unit, and its subject is how texts end — and what an ending lets a reader conclude about the whole work. It opens with the interpretive…https://exercises.lol/video-media/ap_english_literature/unit-9-longer-fiction-or-drama-iii/unit-9-longer-fiction-or-drama-iii.enzh.mp4?v=1793199910-24762026-09-03yes https://exercises.lol/videos/ap_environmental_science/ecosystems2026-10-28https://exercises.lol/video-media/ap_environmental_science/ecosystems/ecosystems.thumb.jpg?v=1793190528The Living World: EcosystemsPicture a grassland. Grass covers the ground everywhere you look. Rabbits and other grazers are common — you can find them all day. But the big cats that hunt…https://exercises.lol/video-media/ap_environmental_science/ecosystems/ecosystems.enzh.mp4?v=1793190528-24862026-08-15yes https://exercises.lol/videos/ap_environmental_science/biodiversity2026-10-27https://exercises.lol/video-media/ap_environmental_science/biodiversity/biodiversity.thumb.jpg?v=1793112233The Living World: BiodiversityA volcano pushes a new island up out of the sea. At first there is nothing on it — bare rock, no soil, no life at all. Fifty years later, it is green. So how…https://exercises.lol/video-media/ap_environmental_science/biodiversity/biodiversity.enzh.mp4?v=1793112233-24772026-08-15yes https://exercises.lol/videos/ap_environmental_science/populations2026-10-30https://exercises.lol/video-media/ap_environmental_science/populations/populations.thumb.jpg?v=1793324045PopulationsIn 1944, twenty-nine reindeer were released onto a small island. There were no predators, and the ground was thick with moss. Within twenty years there were…https://exercises.lol/video-media/ap_environmental_science/populations/populations.enzh.mp4?v=1793324045-24642026-08-15yes https://exercises.lol/videos/ap_environmental_science/earth-systems2026-10-29https://exercises.lol/video-media/ap_environmental_science/earth-systems/earth-systems.thumb.jpg?v=1793302506Earth Systems and ResourcesTwo towns, forty kilometres apart, on opposite sides of one mountain range. One of them gets three metres of rain a year — a rainforest. The other gets less…https://exercises.lol/video-media/ap_environmental_science/earth-systems/earth-systems.enzh.mp4?v=1793302506-24482026-08-15yes https://exercises.lol/videos/ap_environmental_science/land-and-water-use2026-10-30https://exercises.lol/video-media/ap_environmental_science/land-and-water-use/land-and-water-use.thumb.jpg?v=1793403329Land and Water UseThree ordinary places. A logging truck carrying trees that stood here this morning. A pit so wide you could see it from space. A city spreading over the…https://exercises.lol/video-media/ap_environmental_science/land-and-water-use/land-and-water-use.enzh.mp4?v=1793403329-28162026-08-15yes https://exercises.lol/videos/ap_environmental_science/energy-resources-and-consumption2026-10-31https://exercises.lol/video-media/ap_environmental_science/energy-resources-and-consumption/energy-resources-and-consumption.thumb.jpg?v=1793410161Energy Resources and ConsumptionLook at this hole in the ground. A machine digs out soft brown coal, and the power station behind it burns it the same day. Now look at this: three towers on a…https://exercises.lol/video-media/ap_environmental_science/energy-resources-and-consumption/energy-resources-and-consumption.enzh.mp4?v=1793410161-25532026-08-15yes https://exercises.lol/videos/ap_environmental_science/atmospheric-pollution2026-10-29https://exercises.lol/video-media/ap_environmental_science/atmospheric-pollution/atmospheric-pollution.thumb.jpg?v=1793301557Atmospheric PollutionLook at this city. You cannot see the buildings, because you can see the air. Now step inside a kitchen, where one cooking fire fills the room with smoke. Now…https://exercises.lol/video-media/ap_environmental_science/atmospheric-pollution/atmospheric-pollution.enzh.mp4?v=1793301557-24812026-08-15yes https://exercises.lol/videos/ap_environmental_science/aquatic-and-terrestrial-pollution2026-10-29https://exercises.lol/video-media/ap_environmental_science/aquatic-and-terrestrial-pollution/aquatic-and-terrestrial-pollution.thumb.jpg?v=1793302343Aquatic and Terrestrial PollutionLook at this pond. It is bright green, and it is full of life. Every fish in it is dead. Now look at this hill. It is not a hill. It is our rubbish, buried.…https://exercises.lol/video-media/ap_environmental_science/aquatic-and-terrestrial-pollution/aquatic-and-terrestrial-pollution.enzh.mp4?v=1793302343-25172026-08-15yes https://exercises.lol/videos/ap_environmental_science/global-change2026-10-29https://exercises.lol/video-media/ap_environmental_science/global-change/global-change.thumb.jpg?v=1793254730Global ChangeIn nineteen eighty-five, scientists studying the sky above Antarctica found something frightening: a hole in the ozone layer, the thin shield that keeps the…https://exercises.lol/video-media/ap_environmental_science/global-change/global-change.enzh.mp4?v=1793254730-24942026-08-15yes https://exercises.lol/videos/ap_european_history/unit-1-renaissance-and-exploration2026-10-31https://exercises.lol/video-media/ap_european_history/unit-1-renaissance-and-exploration/unit-1-renaissance-and-exploration.thumb.jpg?v=1793411286Unit 1: Renaissance and ExplorationTwo words in the CED tell you how this entire course is marked, and they appear in Unit 1. Varying degrees. The struggle for sovereignty within and among…https://exercises.lol/video-media/ap_european_history/unit-1-renaissance-and-exploration/unit-1-renaissance-and-exploration.enzh.mp4?v=1793411286-26802026-09-03yes https://exercises.lol/videos/ap_european_history/unit-2-age-of-reformation2026-10-31https://exercises.lol/video-media/ap_european_history/unit-2-age-of-reformation/unit-2-age-of-reformation.thumb.jpg?v=1793407722Unit 2: Age of ReformationThere is one way students reliably lose marks in this unit, and it is a study habit rather than a gap in knowledge. They keep religion and politics in separate…https://exercises.lol/video-media/ap_european_history/unit-2-age-of-reformation/unit-2-age-of-reformation.enzh.mp4?v=1793407722-24812026-09-03yes https://exercises.lol/videos/ap_european_history/unit-3-absolutism-and-constitutionalism2026-10-30https://exercises.lol/video-media/ap_european_history/unit-3-absolutism-and-constitutionalism/unit-3-absolutism-and-constitutionalism.thumb.jpg?v=1793403817Unit 3: Absolutism and ConstitutionalismContextualizing state building starts with one phrase: the struggle for sovereignty kept producing varying degrees of political centralisation. Everything in…https://exercises.lol/video-media/ap_european_history/unit-3-absolutism-and-constitutionalism/unit-3-absolutism-and-constitutionalism.enzh.mp4?v=1793403817-24392026-09-03yes https://exercises.lol/videos/ap_european_history/unit-4-scientific-philosophical-and-political-developments2026-10-29https://exercises.lol/video-media/ap_european_history/unit-4-scientific-philosophical-and-political-developments/unit-4-scientific-philosophical-and-political-developments.thumb.jpg?v=1793293159Unit 4: Scientific, Philosophical, and Political DevelopmentsOne sentence contains this entire unit, and it is worth learning in the CED's own words. The spread of Scientific Revolution concepts and practices, and the…https://exercises.lol/video-media/ap_european_history/unit-4-scientific-philosophical-and-political-developments/unit-4-scientific-philosophical-and-political-developments.enzh.mp4?v=1793293159-24732026-09-03yes https://exercises.lol/videos/ap_european_history/unit-5-conflict-crisis-and-reaction2026-10-31https://exercises.lol/video-media/ap_european_history/unit-5-conflict-crisis-and-reaction/unit-5-conflict-crisis-and-reaction.thumb.jpg?v=1793405869Unit 5: Conflict, Crisis, and ReactionContextualizing eighteenth-century states means holding four things together: global commercial competition, the French Revolution, Napoleon, and the…https://exercises.lol/video-media/ap_european_history/unit-5-conflict-crisis-and-reaction/unit-5-conflict-crisis-and-reaction.enzh.mp4?v=1793405869-24412026-09-03yes https://exercises.lol/videos/ap_european_history/unit-6-industrialization-and-its-effects2026-10-30https://exercises.lol/video-media/ap_european_history/unit-6-industrialization-and-its-effects/unit-6-industrialization-and-its-effects.thumb.jpg?v=1793404266Unit 6: Industrialization and Its EffectsOne claim is the spine of this unit. Political revolutions and the complications of industrialisation triggered a range of ideological, governmental and…https://exercises.lol/video-media/ap_european_history/unit-6-industrialization-and-its-effects/unit-6-industrialization-and-its-effects.enzh.mp4?v=1793404266-25542026-09-03yes https://exercises.lol/videos/ap_european_history/unit-7-19th-century-perspectives-and-political-developments2026-10-30https://exercises.lol/video-media/ap_european_history/unit-7-19th-century-perspectives-and-political-developments/unit-7-19th-century-perspectives-and-political-developments.thumb.jpg?v=1793403134Unit 7: 19th-Century Perspectives and Political DevelopmentsContextualizing nineteenth-century perspectives covers about eighteen hundred and fifteen to nineteen hundred and fourteen. If you learn one thing from this…https://exercises.lol/video-media/ap_european_history/unit-7-19th-century-perspectives-and-political-developments/unit-7-19th-century-perspectives-and-political-developments.enzh.mp4?v=1793403134-25122026-09-03yes https://exercises.lol/videos/ap_european_history/unit-8-20th-century-global-conflicts2026-10-31https://exercises.lol/video-media/ap_european_history/unit-8-20th-century-global-conflicts/unit-8-20th-century-global-conflicts.thumb.jpg?v=1793407811Unit 8: 20th-Century Global ConflictsLearn the chain, and this unit becomes navigable. War. Settlement. Economic collapse. Radical movements. Failed appeasement. War again. Most questions ask…https://exercises.lol/video-media/ap_european_history/unit-8-20th-century-global-conflicts/unit-8-20th-century-global-conflicts.enzh.mp4?v=1793407811-25472026-09-03yes https://exercises.lol/videos/ap_european_history/unit-9-cold-war-and-contemporary-europe2026-10-30https://exercises.lol/video-media/ap_european_history/unit-9-cold-war-and-contemporary-europe/unit-9-cold-war-and-contemporary-europe.thumb.jpg?v=1793404268Unit 9: Cold War and Contemporary EuropeThis unit has two halves that must be held together. Division, until 1991. And integration, running alongside it and then beyond it. They are not sequential…https://exercises.lol/video-media/ap_european_history/unit-9-cold-war-and-contemporary-europe/unit-9-cold-war-and-contemporary-europe.enzh.mp4?v=1793404268-25772026-09-03yes https://exercises.lol/videos/ap_human_geography/thinking-geographically2026-10-28https://exercises.lol/video-media/ap_human_geography/thinking-geographically/thinking-geographically.thumb.jpg?v=1793198169Thinking GeographicallyLook at Greenland on a classroom world map. It looks about the size of Africa. It is not. Africa is fourteen times larger. <slow>The map is not lying to you by…https://exercises.lol/video-media/ap_human_geography/thinking-geographically/thinking-geographically.enzh.mp4?v=1793198169-24942026-08-15yes https://exercises.lol/videos/ap_human_geography/population-and-migration-patterns2026-10-29https://exercises.lol/video-media/ap_human_geography/population-and-migration-patterns/population-and-migration-patterns.thumb.jpg?v=1793297571Population and Migration Patterns and ProcessesEight billion people live on this planet. Now look at this street. At one crossing in Tokyo, hundreds of them share a space the size of a school hall.…https://exercises.lol/video-media/ap_human_geography/population-and-migration-patterns/population-and-migration-patterns.enzh.mp4?v=1793297571-25282026-08-15yes https://exercises.lol/videos/ap_human_geography/cultural-patterns-and-processes2026-10-28https://exercises.lol/video-media/ap_human_geography/cultural-patterns-and-processes/cultural-patterns-and-processes.thumb.jpg?v=1793205238Cultural Patterns and ProcessesThis gate stands over a street in Seattle, in the United States. But the roof, the colours and the writing all come from China, nearly ten thousand kilometres…https://exercises.lol/video-media/ap_human_geography/cultural-patterns-and-processes/cultural-patterns-and-processes.enzh.mp4?v=1793205238-24692026-08-15yes https://exercises.lol/videos/ap_human_geography/political-patterns-and-processes2026-10-30https://exercises.lol/video-media/ap_human_geography/political-patterns-and-processes/political-patterns-and-processes.thumb.jpg?v=1793353441Political Patterns and ProcessesHere is a fence. It runs across open ground all the way to the horizon. On the far side stands a city — the same dry land, the same sky. And here is the hall…https://exercises.lol/video-media/ap_human_geography/political-patterns-and-processes/political-patterns-and-processes.enzh.mp4?v=1793353441-24912026-08-15yes https://exercises.lol/videos/ap_human_geography/agriculture-and-rural-land2026-10-31https://exercises.lol/video-media/ap_human_geography/agriculture-and-rural-land/agriculture-and-rural-land.thumb.jpg?v=1793410352Agriculture and Rural Land-Use Patterns and ProcessesTwo farmers. The same job: grow food. Completely different worlds. One drives a machine across a field so wide you cannot see the end of it, and every grain…https://exercises.lol/video-media/ap_human_geography/agriculture-and-rural-land/agriculture-and-rural-land.enzh.mp4?v=1793410352-25122026-08-15yes https://exercises.lol/videos/ap_human_geography/cities-and-urban-land2026-10-29https://exercises.lol/video-media/ap_human_geography/cities-and-urban-land/cities-and-urban-land.thumb.jpg?v=1793257041Cities and Urban Land-Use Patterns and ProcessesMore than half of the people on Earth now live in a city, and that share still grows. A city can pull in money, jobs and ideas from the whole planet. And on a…https://exercises.lol/video-media/ap_human_geography/cities-and-urban-land/cities-and-urban-land.enzh.mp4?v=1793257041-24942026-08-15yes https://exercises.lol/videos/ap_human_geography/industrial-and-economic-development2026-10-30https://exercises.lol/video-media/ap_human_geography/industrial-and-economic-development/industrial-and-economic-development.thumb.jpg?v=1793328324Industrial and Economic Development Patterns and ProcessesAlmost everything in the room around you was made in a factory and carried here on a ship. Two hundred and fifty years ago, almost nobody lived like this. Then…https://exercises.lol/video-media/ap_human_geography/industrial-and-economic-development/industrial-and-economic-development.enzh.mp4?v=1793328324-24822026-08-15yes https://exercises.lol/videos/ap_macroeconomics/basic-economic-concepts2026-10-28https://exercises.lol/video-media/ap_macroeconomics/basic-economic-concepts/basic-economic-concepts.thumb.jpg?v=1793214135Basic Economic ConceptsHere is a result that feels wrong the first time you meet it. Suppose you are faster than your friend at writing code and faster at writing documentation. You…https://exercises.lol/video-media/ap_macroeconomics/basic-economic-concepts/basic-economic-concepts.enzh.mp4?v=1793214135-24492026-08-15yes https://exercises.lol/videos/ap_macroeconomics/economic-indicators-and-the2026-10-31https://exercises.lol/video-media/ap_macroeconomics/economic-indicators-and-the/economic-indicators-and-the.thumb.jpg?v=1793409098Economic Indicators and the Business CycleTwo ordinary scenes. A supermarket aisle, where the same basket of food costs more than it did last year. And a long queue of people, waiting. Neither is an…https://exercises.lol/video-media/ap_macroeconomics/economic-indicators-and-the/economic-indicators-and-the.enzh.mp4?v=1793409098-25972026-08-15yes https://exercises.lol/videos/ap_macroeconomics/national-income-and-price2026-10-29https://exercises.lol/video-media/ap_macroeconomics/national-income-and-price/national-income-and-price.thumb.jpg?v=1793303451National Income and Price DeterminationA government spends ten billion dollars on new railways. How much does the country's output rise? Not ten billion. It can rise by fifty billion. Money spent by…https://exercises.lol/video-media/ap_macroeconomics/national-income-and-price/national-income-and-price.enzh.mp4?v=1793303451-25302026-08-15yes https://exercises.lol/videos/ap_macroeconomics/financial-sector2026-10-30https://exercises.lol/video-media/ap_macroeconomics/financial-sector/financial-sector.thumb.jpg?v=1793339619Financial SectorLook at the money in your hand. It is only paper. It is worth something because everyone agrees to accept it. And out of millions of those agreements grows…https://exercises.lol/video-media/ap_macroeconomics/financial-sector/financial-sector.enzh.mp4?v=1793339619-24752026-08-15yes https://exercises.lol/videos/ap_macroeconomics/long-run-consequences-of2026-10-30https://exercises.lol/video-media/ap_macroeconomics/long-run-consequences-of/long-run-consequences-of.thumb.jpg?v=1793350347Long-Run Consequences of Stabilization PoliciesA government wants to end a recession fast. It spends more, cuts taxes, and the central bank makes borrowing cheap. It works — output rises, jobs come back.…https://exercises.lol/video-media/ap_macroeconomics/long-run-consequences-of/long-run-consequences-of.enzh.mp4?v=1793350347-25062026-08-15yes https://exercises.lol/videos/ap_macroeconomics/open-economy-international-trade2026-10-30https://exercises.lol/video-media/ap_macroeconomics/open-economy-international-trade/open-economy-international-trade.thumb.jpg?v=1793403741Open Economy—International Trade and FinanceCheck the label on almost anything you own. Made somewhere else. It crossed an ocean in a steel box like these, and somebody paid for it in a different money.…https://exercises.lol/video-media/ap_macroeconomics/open-economy-international-trade/open-economy-international-trade.enzh.mp4?v=1793403741-24802026-08-15yes https://exercises.lol/videos/ap_microeconomics/basic-economic-concepts2026-10-29https://exercises.lol/video-media/ap_microeconomics/basic-economic-concepts/basic-economic-concepts.thumb.jpg?v=1793315147Basic Economic ConceptsA day has only twenty-four hours. Think what you want to fit into one: sleep, school, homework, sport, time with friends. Add it up honestly and it comes to…https://exercises.lol/video-media/ap_microeconomics/basic-economic-concepts/basic-economic-concepts.enzh.mp4?v=1793315147-25132026-08-15yes https://exercises.lol/videos/ap_microeconomics/supply-and-demand2026-10-28https://exercises.lol/video-media/ap_microeconomics/supply-and-demand/supply-and-demand.thumb.jpg?v=1793193037Supply and DemandWhy does a cup of coffee cost what it costs? Nobody decided it. There is no committee and no official price list. There are only buyers, who want more when it…https://exercises.lol/video-media/ap_microeconomics/supply-and-demand/supply-and-demand.enzh.mp4?v=1793193037-26392026-08-15yes https://exercises.lol/videos/ap_microeconomics/production-and-cost2026-10-29https://exercises.lol/video-media/ap_microeconomics/production-and-cost/production-and-cost.thumb.jpg?v=1793296488Production, Cost & Perfect CompetitionPicture a small bakery with one kitchen and one oven. Hire your first baker and you get thirty extra loaves a day. Hire a second and you get twenty-six more. A…https://exercises.lol/video-media/ap_microeconomics/production-and-cost/production-and-cost.enzh.mp4?v=1793296488-25352026-08-15yes https://exercises.lol/videos/ap_microeconomics/imperfect-competition2026-10-31https://exercises.lol/video-media/ap_microeconomics/imperfect-competition/imperfect-competition.thumb.jpg?v=1793406984Imperfect CompetitionLook outside the textbook. A car company sets its own price. Your city has one water supplier, and no second one to choose. These firms do not take the price…https://exercises.lol/video-media/ap_microeconomics/imperfect-competition/imperfect-competition.enzh.mp4?v=1793406984-25112026-08-15yes https://exercises.lol/videos/ap_microeconomics/factor-markets2026-10-30https://exercises.lol/video-media/ap_microeconomics/factor-markets/factor-markets.thumb.jpg?v=1793330548Factor MarketsTwo workers. One sews shirts in a clothing factory. The other builds cars on an assembly line. The second earns far more. Why? In this unit the firm is the…https://exercises.lol/video-media/ap_microeconomics/factor-markets/factor-markets.enzh.mp4?v=1793330548-24762026-08-15yes https://exercises.lol/videos/ap_microeconomics/market-failure-and-the2026-10-31https://exercises.lol/video-media/ap_microeconomics/market-failure-and-the/market-failure-and-the.thumb.jpg?v=1793407275Market Failure and the Role of GovernmentLook at this factory. Somebody bought what it makes, and somebody was paid to make it. Both sides are happy with the price. But the smoke is not in that price.…https://exercises.lol/video-media/ap_microeconomics/market-failure-and-the/market-failure-and-the.enzh.mp4?v=1793407275-25002026-08-15yes https://exercises.lol/videos/ap_physics_1/kinematics2026-10-30https://exercises.lol/video-media/ap_physics_1/kinematics/kinematics.thumb.jpg?v=1793325426KinematicsTwo balls leave a table at the same moment. One is simply dropped. The other is fired sideways, hard. Which one hits the floor first? <slow>They land…https://exercises.lol/video-media/ap_physics_1/kinematics/kinematics.enzh.mp4?v=1793325426-25442026-08-15yes https://exercises.lol/videos/ap_physics_1/force-and-translational-dynamics2026-10-30https://exercises.lol/video-media/ap_physics_1/force-and-translational-dynamics/force-and-translational-dynamics.thumb.jpg?v=1793349145Force & Translational DynamicsThree skydivers, far above the ground. Gravity is pulling every one of them down, hard. Yet they hang there, steady, side by side. So why has that pull stopped…https://exercises.lol/video-media/ap_physics_1/force-and-translational-dynamics/force-and-translational-dynamics.enzh.mp4?v=1793349145-26492026-08-15yes https://exercises.lol/videos/ap_physics_1/work-energy-and-power2026-10-29https://exercises.lol/video-media/ap_physics_1/work-energy-and-power/work-energy-and-power.thumb.jpg?v=1793305827Work, Energy, and PowerLook up at the first hill of a roller coaster. A chain drags the train to the top, then lets go. There is no engine on the train — nothing pushes it again for…https://exercises.lol/video-media/ap_physics_1/work-energy-and-power/work-energy-and-power.enzh.mp4?v=1793305827-24872026-08-15yes https://exercises.lol/videos/ap_physics_1/linear-momentum2026-10-29https://exercises.lol/video-media/ap_physics_1/linear-momentum/linear-momentum.thumb.jpg?v=1793316114Linear MomentumFive steel balls hang in a row, just touching. Lift one, let it go, and one ball flies off the far end. Only one. Lift two, and exactly two fly off. Something…https://exercises.lol/video-media/ap_physics_1/linear-momentum/linear-momentum.enzh.mp4?v=1793316114-24692026-08-15yes https://exercises.lol/videos/ap_physics_1/torque-and-rotational-dynamics2026-10-29https://exercises.lol/video-media/ap_physics_1/torque-and-rotational-dynamics/torque-and-rotational-dynamics.thumb.jpg?v=1793303292Torque and Rotational DynamicsPush a heavy door right next to its hinge, as hard as you can. It barely moves. Now push with the same force, out at the handle — and it swings wide open. Same…https://exercises.lol/video-media/ap_physics_1/torque-and-rotational-dynamics/torque-and-rotational-dynamics.enzh.mp4?v=1793303292-24612026-08-15yes https://exercises.lol/videos/ap_physics_1/energy-and-momentum-of2026-10-30https://exercises.lol/video-media/ap_physics_1/energy-and-momentum-of/energy-and-momentum-of.thumb.jpg?v=1793331801Energy and Momentum of Rotating SystemsWatch a skater spinning with her arms stretched out. She pulls them in — and suddenly she spins much faster. Nobody pushed her. No motor started. So where did…https://exercises.lol/video-media/ap_physics_1/energy-and-momentum-of/energy-and-momentum-of.enzh.mp4?v=1793331801-24742026-08-15yes https://exercises.lol/videos/ap_physics_1/oscillations2026-10-29https://exercises.lol/video-media/ap_physics_1/oscillations/oscillations.thumb.jpg?v=1793313411OscillationsTwo identical springs, two identical masses. Pull one of them far down. Pull the other only a little. Let go of both at the same moment. Which one gets back…https://exercises.lol/video-media/ap_physics_1/oscillations/oscillations.enzh.mp4?v=1793313411-24682026-08-15yes https://exercises.lol/videos/ap_physics_1/fluids2026-10-29https://exercises.lol/video-media/ap_physics_1/fluids/fluids.thumb.jpg?v=1793304323FluidsA steel nail dropped into water goes straight to the bottom. Now look at this ship. It is built from the same steel, tens of thousands of tonnes of it, and it…https://exercises.lol/video-media/ap_physics_1/fluids/fluids.enzh.mp4?v=1793304323-24862026-08-15yes https://exercises.lol/videos/ap_physics_2/thermodynamics2026-10-29https://exercises.lol/video-media/ap_physics_2/thermodynamics/thermodynamics.thumb.jpg?v=1793291180ThermodynamicsPut a hot cup of coffee on a table. It always cools down. It never warms back up by taking heat out of the cool room. Both directions would balance the energy…https://exercises.lol/video-media/ap_physics_2/thermodynamics/thermodynamics.enzh.mp4?v=1793291180-25362026-08-15yes https://exercises.lol/videos/ap_physics_2/electric-force-field-potential2026-10-29https://exercises.lol/video-media/ap_physics_2/electric-force-field-potential/electric-force-field-potential.thumb.jpg?v=1793236662Electric Force, Field, and PotentialA thundercloud is a charge factory. Ice crystals crash inside it, and electrons collect at the bottom of the cloud. The ground below turns positive. Nothing…https://exercises.lol/video-media/ap_physics_2/electric-force-field-potential/electric-force-field-potential.enzh.mp4?v=1793236662-24842026-08-15yes https://exercises.lol/videos/ap_physics_2/electric-circuits2026-10-28https://exercises.lol/video-media/ap_physics_2/electric-circuits/electric-circuits.thumb.jpg?v=1793213452Electric CircuitsYou flip a switch, and the light comes on at once. So the electrons must be racing down the wire. They are not. Inside copper, electrons crawl — less than a…https://exercises.lol/video-media/ap_physics_2/electric-circuits/electric-circuits.enzh.mp4?v=1793213452-24652026-08-15yes https://exercises.lol/videos/ap_physics_2/magnetism-electromagnetism2026-10-28https://exercises.lol/video-media/ap_physics_2/magnetism-electromagnetism/magnetism-electromagnetism.thumb.jpg?v=1793181067Magnetism and ElectromagnetismHigh over the Arctic, the night sky glows green. These curtains of light are not fire. They are charged particles from the Sun, arriving at a million…https://exercises.lol/video-media/ap_physics_2/magnetism-electromagnetism/magnetism-electromagnetism.enzh.mp4?v=1793181067-25612026-08-15yes https://exercises.lol/videos/ap_physics_2/geometric-optics2026-10-28https://exercises.lol/video-media/ap_physics_2/geometric-optics/geometric-optics.thumb.jpg?v=1793205139Geometric OpticsPut a straight pencil into a glass of water, and it looks broken. Look into the bowl of a shiny spoon, and your face is upside down. Nothing bent, and nothing…https://exercises.lol/video-media/ap_physics_2/geometric-optics/geometric-optics.enzh.mp4?v=1793205139-25712026-08-15yes https://exercises.lol/videos/ap_physics_2/waves-sound-physical-optics2026-11-04https://exercises.lol/video-media/ap_physics_2/waves-sound-physical-optics/waves-sound-physical-optics.thumb.jpg?v=1793790917Waves, Sound, and Physical OpticsBlow a soap bubble and look closely. The film is thinner than a hair and has no colour of its own, and the light falling on it is plain white light. Yet the…https://exercises.lol/video-media/ap_physics_2/waves-sound-physical-optics/waves-sound-physical-optics.enzh.mp4?v=1793790917-24702026-08-15yes https://exercises.lol/videos/ap_physics_2/modern-physics2026-10-29https://exercises.lol/video-media/ap_physics_2/modern-physics/modern-physics.thumb.jpg?v=1793308612Modern PhysicsBy nineteen hundred, physics looked finished. Then three experiments broke it. A hot glowing object gave out the wrong colours. Light falling on a metal…https://exercises.lol/video-media/ap_physics_2/modern-physics/modern-physics.enzh.mp4?v=1793308612-25712026-08-15yes https://exercises.lol/videos/ap_physics_c_em/charges-fields-gauss2026-10-29https://exercises.lol/video-media/ap_physics_c_em/charges-fields-gauss/charges-fields-gauss.thumb.jpg?v=1793235022Electric Charges, Fields, and Gauss's LawA lightning bolt hits a car. Inside, the people feel nothing at all. Why? The metal shell around them is a conductor. Charge races over its outside surface…https://exercises.lol/video-media/ap_physics_c_em/charges-fields-gauss/charges-fields-gauss.enzh.mp4?v=1793235022-25922026-08-15yes https://exercises.lol/videos/ap_physics_c_em/electric-potential2026-10-28https://exercises.lol/video-media/ap_physics_c_em/electric-potential/electric-potential.thumb.jpg?v=1793183336Electric PotentialLook at these numbers. A small battery says one point five volts. A car battery says twelve. A high-voltage transmission line carries four hundred thousand. A…https://exercises.lol/video-media/ap_physics_c_em/electric-potential/electric-potential.enzh.mp4?v=1793183336-24812026-08-15yes https://exercises.lol/videos/ap_physics_c_em/conductors-capacitors2026-10-28https://exercises.lol/video-media/ap_physics_c_em/conductors-capacitors/conductors-capacitors.thumb.jpg?v=1793212826Conductors and CapacitorsA plane is struck by lightning about once a year, and the people inside feel almost nothing. A car in a thunderstorm is one of the safest places to sit. Why?…https://exercises.lol/video-media/ap_physics_c_em/conductors-capacitors/conductors-capacitors.enzh.mp4?v=1793212826-25072026-08-15yes https://exercises.lol/videos/ap_physics_c_em/circuits2026-10-30https://exercises.lol/video-media/ap_physics_c_em/circuits/circuits.thumb.jpg?v=1793353385Electric CircuitsYou flip a switch, and the lamp lights at once. So the electrons must be racing down the wire — right? Not at all. Inside that copper wire, the carriers crawl…https://exercises.lol/video-media/ap_physics_c_em/circuits/circuits.enzh.mp4?v=1793353385-25232026-08-15yes https://exercises.lol/videos/ap_physics_c_em/magnetic-fields2026-10-28https://exercises.lol/video-media/ap_physics_c_em/magnetic-fields/magnetic-fields.thumb.jpg?v=1793185496Magnetic Fields and ElectromagnetismLook north on a clear winter night, far enough north, and the sky glows green. Those lights are switched on by a magnetic field. The Sun throws charged…https://exercises.lol/video-media/ap_physics_c_em/magnetic-fields/magnetic-fields.enzh.mp4?v=1793185496-27642026-08-15yes https://exercises.lol/videos/ap_physics_c_em/electromagnetic-induction2026-10-28https://exercises.lol/video-media/ap_physics_c_em/electromagnetic-induction/electromagnetic-induction.thumb.jpg?v=1793188042Electromagnetic InductionAlmost every watt of electricity you have ever used began the same way, with a magnet and a coil of wire moving past each other. No fuel, no burning: only…https://exercises.lol/video-media/ap_physics_c_em/electromagnetic-induction/electromagnetic-induction.enzh.mp4?v=1793188042-25512026-08-15yes https://exercises.lol/videos/ap_physics_c_mech/kinematics2026-10-30https://exercises.lol/video-media/ap_physics_c_mech/kinematics/kinematics.thumb.jpg?v=1793325812KinematicsA rocket lifts off. Every second, its engine burns harder, so its acceleration keeps growing. Now try to find its speed with the equations from your first…https://exercises.lol/video-media/ap_physics_c_mech/kinematics/kinematics.enzh.mp4?v=1793325812-24512026-08-15yes https://exercises.lol/videos/ap_physics_c_mech/force-translational-dynamics2026-10-30https://exercises.lol/video-media/ap_physics_c_mech/force-translational-dynamics/force-translational-dynamics.thumb.jpg?v=1793333449Force and Translational DynamicsA cart runs around a vertical loop. At the very top it is completely upside down, with nothing holding it up. Why does it not fall off? The answer is not some…https://exercises.lol/video-media/ap_physics_c_mech/force-translational-dynamics/force-translational-dynamics.enzh.mp4?v=1793333449-25462026-08-15yes https://exercises.lol/videos/ap_physics_c_mech/work-energy-power2026-10-29https://exercises.lol/video-media/ap_physics_c_mech/work-energy-power/work-energy-power.thumb.jpg?v=1793317590Work, Energy, and PowerA block slides into a spring and squashes it until it stops. How far does the spring compress? Try that with a kinematic equation. You cannot — the force grows…https://exercises.lol/video-media/ap_physics_c_mech/work-energy-power/work-energy-power.enzh.mp4?v=1793317590-24662026-08-15yes https://exercises.lol/videos/ap_physics_c_mech/linear-momentum2026-10-28https://exercises.lol/video-media/ap_physics_c_mech/linear-momentum/linear-momentum.thumb.jpg?v=1793195653Linear MomentumA car stops in a crash. With an airbag, the driver walks away. Without one, they do not. In both cases the momentum change is exactly the same — from full…https://exercises.lol/video-media/ap_physics_c_mech/linear-momentum/linear-momentum.enzh.mp4?v=1793195653-24192026-08-15yes https://exercises.lol/videos/ap_physics_c_mech/torque-rotational-dynamics2026-10-30https://exercises.lol/video-media/ap_physics_c_mech/torque-rotational-dynamics/torque-rotational-dynamics.thumb.jpg?v=1793348479Torque and Rotational DynamicsPush a door at the handle and it swings open easily. Now push just as hard, right next to the hinge. Almost nothing happens. The force was the same both times.…https://exercises.lol/video-media/ap_physics_c_mech/torque-rotational-dynamics/torque-rotational-dynamics.enzh.mp4?v=1793348479-24412026-08-15yes https://exercises.lol/videos/ap_physics_c_mech/energy-and-momentum-of2026-10-29https://exercises.lol/video-media/ap_physics_c_mech/energy-and-momentum-of/energy-and-momentum-of.thumb.jpg?v=1793304293Energy and Momentum of Rotating SystemsWatch a figure skater spin. Arms stretched out, she turns slowly. She pulls her arms in — and without pushing off anything, she spins much faster. Nobody…https://exercises.lol/video-media/ap_physics_c_mech/energy-and-momentum-of/energy-and-momentum-of.enzh.mp4?v=1793304293-24922026-08-15yes https://exercises.lol/videos/ap_physics_c_mech/oscillations2026-10-29https://exercises.lol/video-media/ap_physics_c_mech/oscillations/oscillations.thumb.jpg?v=1793296607OscillationsIn a science museum, a brass ball hangs from a very long wire. It swings all day above a marked floor, untouched. Every swing takes the same time as the last.…https://exercises.lol/video-media/ap_physics_c_mech/oscillations/oscillations.enzh.mp4?v=1793296607-24932026-08-15yes https://exercises.lol/videos/ap_precalculus/polynomial-rational-functions2026-10-30https://exercises.lol/video-media/ap_precalculus/polynomial-rational-functions/polynomial-rational-functions.thumb.jpg?v=1793319970Polynomial & Rational FunctionsLook at this curve. It rises, then falls, then rises again — these are its turning points. It cuts across the horizontal axis — these are the roots, where the…https://exercises.lol/video-media/ap_precalculus/polynomial-rational-functions/polynomial-rational-functions.enzh.mp4?v=1793319970-210342026-08-15yes https://exercises.lol/videos/ap_precalculus/exponential-logarithmic-functions2026-10-31https://exercises.lol/video-media/ap_precalculus/exponential-logarithmic-functions/exponential-logarithmic-functions.thumb.jpg?v=1793406916Exponential & Logarithmic FunctionsHere are two ways for a quantity to grow. The blue line grows steadily, adding the same amount every step. The other one is doubling — multiplying by the same…https://exercises.lol/video-media/ap_precalculus/exponential-logarithmic-functions/exponential-logarithmic-functions.enzh.mp4?v=1793406916-28452026-08-15yes https://exercises.lol/videos/ap_precalculus/trigonometric-polar-functions2026-10-30https://exercises.lol/video-media/ap_precalculus/trigonometric-polar-functions/trigonometric-polar-functions.thumb.jpg?v=1793329810Trigonometric & Polar FunctionsWatch a point travel around a circle at a steady rate. Its height rises, falls, and rises again, over and over. Trace that height against time, and you get a…https://exercises.lol/video-media/ap_precalculus/trigonometric-polar-functions/trigonometric-polar-functions.enzh.mp4?v=1793329810-24872026-08-15yes https://exercises.lol/videos/ap_precalculus/functions-involving-parameters-vectors2026-10-30https://exercises.lol/video-media/ap_precalculus/functions-involving-parameters-vectors/functions-involving-parameters-vectors.thumb.jpg?v=1793349361Functions Involving Parameters, Vectors, and MatricesLook at this roller coaster. At every moment the car has two facts: where it is, and which way it is going. One equation cannot hold both. This planet runs a…https://exercises.lol/video-media/ap_precalculus/functions-involving-parameters-vectors/functions-involving-parameters-vectors.enzh.mp4?v=1793349361-24832026-08-15yes https://exercises.lol/videos/ap_psychology/biological-bases-of-behavior2026-10-31https://exercises.lol/video-media/ap_psychology/biological-bases-of-behavior/biological-bases-of-behavior.thumb.jpg?v=1793408809Biological Bases of BehaviorThe teacher hands out the exam paper. Before you have read a single word, your heart is already faster and your hands are cold. You did not choose that.…https://exercises.lol/video-media/ap_psychology/biological-bases-of-behavior/biological-bases-of-behavior.enzh.mp4?v=1793408809-210972026-09-03yes https://exercises.lol/videos/ap_psychology/cognition2026-10-29https://exercises.lol/video-media/ap_psychology/cognition/cognition.thumb.jpg?v=1793304043CognitionLook at a sentence with a letter missing and you read it anyway. Nobody had to tell you what the letter was. Your brain supplied it, instantly, without asking…https://exercises.lol/video-media/ap_psychology/cognition/cognition.enzh.mp4?v=1793304043-210742026-09-03yes https://exercises.lol/videos/ap_psychology/development-and-learning2026-10-30https://exercises.lol/video-media/ap_psychology/development-and-learning/development-and-learning.thumb.jpg?v=1793403288Development and LearningA four-year-old picks up a heavy glass marble and tries to bounce it on the floor. He is not being silly. He had a rule for round things: round things bounce.…https://exercises.lol/video-media/ap_psychology/development-and-learning/development-and-learning.enzh.mp4?v=1793403288-27382026-09-03yes https://exercises.lol/videos/ap_psychology/social-psychology-and-personality2026-10-29https://exercises.lol/video-media/ap_psychology/social-psychology-and-personality/social-psychology-and-personality.thumb.jpg?v=1793306940Social Psychology and PersonalityA driver cuts in front of you and you decide they are rude. Later you cut in front of someone, and you know exactly why: you were late, and the other lane was…https://exercises.lol/video-media/ap_psychology/social-psychology-and-personality/social-psychology-and-personality.enzh.mp4?v=1793306940-26242026-09-03yes https://exercises.lol/videos/ap_psychology/mental-and-physical-health2026-10-30https://exercises.lol/video-media/ap_psychology/mental-and-physical-health/mental-and-physical-health.thumb.jpg?v=1793320587Mental and Physical HealthOne person collects bus tickets and can name every route in the city. Another cannot leave the house to go to work. Only one of those is a disorder, and it is…https://exercises.lol/video-media/ap_psychology/mental-and-physical-health/mental-and-physical-health.enzh.mp4?v=1793320587-25572026-09-03yes https://exercises.lol/videos/ap_statistics/one-variable-data2026-10-29https://exercises.lol/video-media/ap_statistics/one-variable-data/one-variable-data.thumb.jpg?v=1793316199Exploring One-Variable DataMeasure the same thing twenty times and you will not get the same answer twenty times. Twenty students measure the same table. The values vary. That is not a…https://exercises.lol/video-media/ap_statistics/one-variable-data/one-variable-data.enzh.mp4?v=1793316199-25432026-08-15yes https://exercises.lol/videos/ap_statistics/exploring-two-variable-data2026-10-28https://exercises.lol/video-media/ap_statistics/exploring-two-variable-data/exploring-two-variable-data.thumb.jpg?v=1793205974Exploring Two-Variable DataThirty children from one primary school. For each child, two numbers: shoe size, and a reading test score. Plot one point per child. The pattern is hard to…https://exercises.lol/video-media/ap_statistics/exploring-two-variable-data/exploring-two-variable-data.enzh.mp4?v=1793205974-24682026-08-15yes https://exercises.lol/videos/ap_statistics/collecting-data2026-10-29https://exercises.lol/video-media/ap_statistics/collecting-data/collecting-data.thumb.jpg?v=1793304292Collecting DataAn online poll collects thirty thousand replies. A careful survey asks only one thousand people. Which is closer to the truth? The small one, almost every…https://exercises.lol/video-media/ap_statistics/collecting-data/collecting-data.enzh.mp4?v=1793304292-24502026-08-15yes https://exercises.lol/videos/ap_statistics/probability-random-variables-and2026-10-31https://exercises.lol/video-media/ap_statistics/probability-random-variables-and/probability-random-variables-and.thumb.jpg?v=1793407033Probability, Random Variables, and Probability DistributionsA basketball player makes five shots in a row. The crowd is sure she is hot tonight. But watch what chance alone can do. Flip a fair coin twenty times. There…https://exercises.lol/video-media/ap_statistics/probability-random-variables-and/probability-random-variables-and.enzh.mp4?v=1793407033-25192026-08-15yes https://exercises.lol/videos/ap_statistics/sampling-distributions2026-10-30https://exercises.lol/video-media/ap_statistics/sampling-distributions/sampling-distributions.thumb.jpg?v=1793404725Sampling DistributionsTwo thousand students go to this school, and some of them cycle here. We want to know what share. Nobody can ask all two thousand, so we ask a random hundred.…https://exercises.lol/video-media/ap_statistics/sampling-distributions/sampling-distributions.enzh.mp4?v=1793404725-24522026-08-15yes https://exercises.lol/videos/ap_statistics/inference-for-categorical-data2026-10-30https://exercises.lol/video-media/ap_statistics/inference-for-categorical-data/inference-for-categorical-data.thumb.jpg?v=1793404247Inference for Categorical Data: ProportionsA city wants to know how many people support a new policy. We cannot ask everyone, so we ask two hundred at random. A hundred and twenty say yes — sixty…https://exercises.lol/video-media/ap_statistics/inference-for-categorical-data/inference-for-categorical-data.enzh.mp4?v=1793404247-24722026-08-15yes https://exercises.lol/videos/ap_statistics/inference-for-quantitative-data2026-10-31https://exercises.lol/video-media/ap_statistics/inference-for-quantitative-data/inference-for-quantitative-data.thumb.jpg?v=1793407354Inference for Quantitative Data: MeansYou already know the heart of inference. Take a sample, find its mean, then do it again and again. Even when the population is lopsided, those sample means…https://exercises.lol/video-media/ap_statistics/inference-for-quantitative-data/inference-for-quantitative-data.enzh.mp4?v=1793407354-24572026-08-15yes https://exercises.lol/videos/ap_statistics/inference-for-categorical-data-chi-82026-10-30https://exercises.lol/video-media/ap_statistics/inference-for-categorical-data-chi-8/inference-for-categorical-data-chi-8.thumb.jpg?v=1793327968Inference for Categorical Data: Chi-SquareRoll a fair die sixty times. Every face should come up ten times. But it never does — eight here, thirteen there. The gaps are always there. So roll another…https://exercises.lol/video-media/ap_statistics/inference-for-categorical-data-chi-8/inference-for-categorical-data-chi-8.enzh.mp4?v=1793327968-24682026-08-15yes https://exercises.lol/videos/ap_statistics/inference-for-quantitative-data-slopes-92026-10-28https://exercises.lol/video-media/ap_statistics/inference-for-quantitative-data-slopes-9/inference-for-quantitative-data-slopes-9.thumb.jpg?v=1793185096Inference for Quantitative Data: SlopesHere is one class on a scatterplot: hours of revision along the bottom, test score up the side. The line of best fit climbs. But this is only one class. Take a…https://exercises.lol/video-media/ap_statistics/inference-for-quantitative-data-slopes-9/inference-for-quantitative-data-slopes-9.enzh.mp4?v=1793185096-24792026-08-15yes https://exercises.lol/videos/ap_us_history/period-1-1491-16072026-10-29https://exercises.lol/video-media/ap_us_history/period-1-1491-1607/period-1-1491-1607.thumb.jpg?v=1793316946Period 1: 1491 to 1607In 1491 North America was not empty and it was not one place. It held hundreds of societies, farming, hunting, fishing and trading, and they differed from each…https://exercises.lol/video-media/ap_us_history/period-1-1491-1607/period-1-1491-1607.enzh.mp4?v=1793316946-24662026-09-03yes https://exercises.lol/videos/ap_us_history/period-2-1607-17542026-10-29https://exercises.lol/video-media/ap_us_history/period-2-1607-1754/period-2-1607-1754.thumb.jpg?v=1793303578Period 2: 1607 to 1754Two English colonies, founded within twenty years of each other by people from the same country under the same crown. One grows tobacco with enslaved labour on…https://exercises.lol/video-media/ap_us_history/period-2-1607-1754/period-2-1607-1754.enzh.mp4?v=1793303578-25062026-09-03yes https://exercises.lol/videos/ap_us_history/period-3-1754-18002026-10-31https://exercises.lol/video-media/ap_us_history/period-3-1754-1800/period-3-1754-1800.thumb.jpg?v=1793411068Period 3: 1754 to 1800Britain wins the war, takes half a continent, and destroys its main rival in North America. Twelve years later its colonies are in open rebellion. Those two…https://exercises.lol/video-media/ap_us_history/period-3-1754-1800/period-3-1754-1800.enzh.mp4?v=1793411068-25472026-09-03yes https://exercises.lol/videos/ap_us_history/period-4-1800-18482026-10-31https://exercises.lol/video-media/ap_us_history/period-4-1800-1848/period-4-1800-1848.thumb.jpg?v=1793411251Period 4: 1800 to 1848In 1825 a canal opens, and a bag of wheat that took three weeks to reach a city now takes eight days at a tenth of the cost. Everything follows from that.…https://exercises.lol/video-media/ap_us_history/period-4-1800-1848/period-4-1800-1848.enzh.mp4?v=1793411251-25382026-09-03yes https://exercises.lol/videos/ap_us_history/period-5-1844-18772026-10-31https://exercises.lol/video-media/ap_us_history/period-5-1844-1877/period-5-1844-1877.thumb.jpg?v=1793407567Period 5: 1844 to 1877In one decade a country doubles its territory. That sounds like a triumph and it brings one question with it: will slavery go there? Every compromise from then…https://exercises.lol/video-media/ap_us_history/period-5-1844-1877/period-5-1844-1877.enzh.mp4?v=1793407567-24532026-09-03yes https://exercises.lol/videos/ap_us_history/period-6-1865-18982026-10-30https://exercises.lol/video-media/ap_us_history/period-6-1865-1898/period-6-1865-1898.thumb.jpg?v=1793403772Period 6: 1865 to 1898Here is the puzzle at the centre of this period. An American farmer in 1890 grew more wheat than his father ever had, with better machines, on more land…https://exercises.lol/video-media/ap_us_history/period-6-1865-1898/period-6-1865-1898.enzh.mp4?v=1793403772-24362026-09-03yes https://exercises.lol/videos/ap_us_history/period-7-1890-19452026-10-31https://exercises.lol/video-media/ap_us_history/period-7-1890-1945/period-7-1890-1945.thumb.jpg?v=1793411282Period 7: 1890 to 1945This is the longest period on the course and the densest, and students drown in it because they try to remember it as one story. It is three. Federal power…https://exercises.lol/video-media/ap_us_history/period-7-1890-1945/period-7-1890-1945.enzh.mp4?v=1793411282-24602026-09-03yes https://exercises.lol/videos/ap_us_history/period-8-1945-19802026-10-30https://exercises.lol/video-media/ap_us_history/period-8-1945-1980/period-8-1945-1980.thumb.jpg?v=1793403061Period 8: 1945 to 1980Two arguments dominate this period, and they look unrelated until you see what they share. How far should the United States go to contain communism abroad? And…https://exercises.lol/video-media/ap_us_history/period-8-1945-1980/period-8-1945-1980.enzh.mp4?v=1793403061-24062026-09-03yes https://exercises.lol/videos/ap_us_history/period-9-1980-present2026-10-31https://exercises.lol/video-media/ap_us_history/period-9-1980-present/period-9-1980-present.thumb.jpg?v=1793406314Period 9: 1980 to the presentThis period is short in topics and wide in scope, and the exam treats it as the culmination of the whole course. Three arguments that have run since the…https://exercises.lol/video-media/ap_us_history/period-9-1980-present/period-9-1980-present.enzh.mp4?v=1793406314-23442026-09-03yes https://exercises.lol/videos/ap_world_history/unit-1-the-global-tapestry2026-10-28https://exercises.lol/video-media/ap_world_history/unit-1-the-global-tapestry/unit-1-the-global-tapestry.thumb.jpg?v=1793191797Unit 1: The Global TapestryUnit 1 asks you to hold six regions of the world in your head at once, and students try to do it by memorising six separate stories. That is why the unit feels…https://exercises.lol/video-media/ap_world_history/unit-1-the-global-tapestry/unit-1-the-global-tapestry.enzh.mp4?v=1793191797-24732026-09-03yes https://exercises.lol/videos/ap_world_history/unit-2-networks-of-exchange2026-10-29https://exercises.lol/video-media/ap_world_history/unit-2-networks-of-exchange/unit-2-networks-of-exchange.thumb.jpg?v=1793262610Unit 2: Networks of ExchangeSilk, porcelain, spices, gold, salt. Students spend hours learning who traded what, and then a question asks why trade grew and the list is no help at all.…https://exercises.lol/video-media/ap_world_history/unit-2-networks-of-exchange/unit-2-networks-of-exchange.enzh.mp4?v=1793262610-24102026-09-03yes https://exercises.lol/videos/ap_world_history/unit-3-land-based-empires2026-10-28https://exercises.lol/video-media/ap_world_history/unit-3-land-based-empires/unit-3-land-based-empires.thumb.jpg?v=1793187529Unit 3: Land-Based EmpiresEvery ruler in this unit faces the same practical problem. You have conquered territory that is weeks of travel from your capital, and the people who actually…https://exercises.lol/video-media/ap_world_history/unit-3-land-based-empires/unit-3-land-based-empires.enzh.mp4?v=1793187529-23342026-09-03yes https://exercises.lol/videos/ap_world_history/unit-4-transoceanic-interconnections2026-10-31https://exercises.lol/video-media/ap_world_history/unit-4-transoceanic-interconnections/unit-4-transoceanic-interconnections.thumb.jpg?v=1793404889Unit 4: Transoceanic InterconnectionsAsk most students why Europeans sailed and you get a name — Columbus, da Gama, Magellan. The explorer is the least useful answer available. What actually made…https://exercises.lol/video-media/ap_world_history/unit-4-transoceanic-interconnections/unit-4-transoceanic-interconnections.enzh.mp4?v=1793404889-23972026-09-03yes https://exercises.lol/videos/ap_world_history/unit-5-revolutions2026-10-31https://exercises.lol/video-media/ap_world_history/unit-5-revolutions/unit-5-revolutions.thumb.jpg?v=1793406999Unit 5: RevolutionsThis unit has two engines running at once. An intellectual revolution that changed how people justified political authority, and an industrial revolution that…https://exercises.lol/video-media/ap_world_history/unit-5-revolutions/unit-5-revolutions.enzh.mp4?v=1793406999-24052026-09-03yes https://exercises.lol/videos/ap_world_history/unit-6-consequences-of-industrialization2026-10-29https://exercises.lol/video-media/ap_world_history/unit-6-consequences-of-industrialization/unit-6-consequences-of-industrialization.thumb.jpg?v=1793261784Unit 6: Consequences of IndustrializationThis is the unit on the consequences of industrialisation, 1750 to 1900. One distinction decides most of the marks in this unit, and it is easy to state and…https://exercises.lol/video-media/ap_world_history/unit-6-consequences-of-industrialization/unit-6-consequences-of-industrialization.enzh.mp4?v=1793261784-23742026-09-03yes https://exercises.lol/videos/ap_world_history/unit-7-global-conflict2026-10-30https://exercises.lol/video-media/ap_world_history/unit-7-global-conflict/unit-7-global-conflict.thumb.jpg?v=1793403191Unit 7: Global ConflictThe organising question of this unit is not what happened in the wars. Campaigns and battles earn almost nothing on this exam. The question is why the…https://exercises.lol/video-media/ap_world_history/unit-7-global-conflict/unit-7-global-conflict.enzh.mp4?v=1793403191-25142026-09-03yes https://exercises.lol/videos/ap_world_history/unit-8-cold-war-and-decolonization2026-10-29https://exercises.lol/video-media/ap_world_history/unit-8-cold-war-and-decolonization/unit-8-cold-war-and-decolonization.thumb.jpg?v=1793304828Unit 8: Cold War and DecolonizationTwo processes run through this unit at the same time: a global ideological rivalry, and the end of empire. Studied separately they are twice the work and half…https://exercises.lol/video-media/ap_world_history/unit-8-cold-war-and-decolonization/unit-8-cold-war-and-decolonization.enzh.mp4?v=1793304828-25202026-09-03yes https://exercises.lol/videos/ap_world_history/unit-9-globalization2026-10-29https://exercises.lol/video-media/ap_world_history/unit-9-globalization/unit-9-globalization.thumb.jpg?v=1793238117Unit 9: GlobalizationUnit 9's central move is evaluative rather than narrative. Almost every development it names produced a benefit and a cost, and the questions reward answers…https://exercises.lol/video-media/ap_world_history/unit-9-globalization/unit-9-globalization.enzh.mp4?v=1793238117-24592026-09-03yes https://exercises.lol/videos/aqa_gcse_biology/cell-biology2026-10-30https://exercises.lol/video-media/aqa_gcse_biology/cell-biology/cell-biology.thumb.jpg?v=1793354936Topic 1: Cell biologyCells are the basic unit of all forms of life. Plant and animal cells keep their genetic material inside a nucleus; bacterial cells do not, carrying a single…https://exercises.lol/video-media/aqa_gcse_biology/cell-biology/cell-biology.enzh.mp4?v=1793354936-228942026-10-30yes https://exercises.lol/videos/aqa_gcse_biology/organisation2026-11-08https://exercises.lol/video-media/aqa_gcse_biology/organisation/organisation.thumb.jpg?v=1794123744Topic 2: OrganisationWhy it matters. On 3 December 1967, at Groote Schuur Hospital in Cape Town, the surgeon Christiaan Barnard and his team carried out the first human-to-human…https://exercises.lol/video-media/aqa_gcse_biology/organisation/organisation.enzh.mp4?v=1794123744-211292026-10-30yes https://exercises.lol/videos/aqa_gcse_biology/infection-and-response2026-10-30https://exercises.lol/video-media/aqa_gcse_biology/infection-and-response/infection-and-response.thumb.jpg?v=1793352667Topic 3: Infection and responsePathogens are microorganisms that cause infectious disease — viruses, bacteria, protists and fungi, in animals and in plants. The body answers with barriers…https://exercises.lol/video-media/aqa_gcse_biology/infection-and-response/infection-and-response.enzh.mp4?v=1793352667-221372026-10-30yes https://exercises.lol/videos/aqa_gcse_biology/bioenergetics2026-11-08https://exercises.lol/video-media/aqa_gcse_biology/bioenergetics/bioenergetics.thumb.jpg?v=1794124408Topic 4: BioenergeticsWhy it matters. On 17 August 1771 the English chemist Joseph Priestley put a sprig of mint into a sealed glass jar in which a candle had burned until it went…https://exercises.lol/video-media/aqa_gcse_biology/bioenergetics/bioenergetics.enzh.mp4?v=1794124408-210322026-10-30yes https://exercises.lol/videos/aqa_gcse_biology/homeostasis-and-response2026-11-08https://exercises.lol/video-media/aqa_gcse_biology/homeostasis-and-response/homeostasis-and-response.thumb.jpg?v=1794127140Topic 5: Homeostasis and responseWhy it matters. On 11 January 1922, at Toronto General Hospital, a 14-year-old boy called Leonard Thompson was given the first injection of insulin ever tried…https://exercises.lol/video-media/aqa_gcse_biology/homeostasis-and-response/homeostasis-and-response.enzh.mp4?v=1794127140-218542026-10-28yes https://exercises.lol/videos/aqa_gcse_biology/inheritance-variation-and-evolution2026-11-08https://exercises.lol/video-media/aqa_gcse_biology/inheritance-variation-and-evolution/inheritance-variation-and-evolution.thumb.jpg?v=1794124940Topic 6: Inheritance, variation and evolutionWhy it matters. On 8 February and 8 March 1865, a monk called Gregor Mendel read a paper to the Natural History Society in Brünn (now Brno, in the Czech…https://exercises.lol/video-media/aqa_gcse_biology/inheritance-variation-and-evolution/inheritance-variation-and-evolution.enzh.mp4?v=1794124940-213462026-10-30yes https://exercises.lol/videos/aqa_gcse_biology/ecology2026-11-08https://exercises.lol/video-media/aqa_gcse_biology/ecology/ecology.thumb.jpg?v=1794124376Topic 7: EcologyWhy it matters. In 1926 the last wolves in Yellowstone National Park, in the United States, were killed. Without them, elk herds grew and grazed the young…https://exercises.lol/video-media/aqa_gcse_biology/ecology/ecology.enzh.mp4?v=1794124376-214582026-10-30yes https://exercises.lol/videos/aqa_gcse_chemistry/atomic-structure-and-periodic-table2026-10-31https://exercises.lol/video-media/aqa_gcse_chemistry/atomic-structure-and-periodic-table/atomic-structure-and-periodic-table.thumb.jpg?v=1793406220Topic 1: Atomic structure and the periodic tableBegin with particles. Proton number identifies the element; electron arrangement helps explain reaction patterns. We will use evidence to choose a separation…https://exercises.lol/video-media/aqa_gcse_chemistry/atomic-structure-and-periodic-table/atomic-structure-and-periodic-table.enzh.mp4?v=1793406220-28362026-10-28yes https://exercises.lol/videos/aqa_gcse_chemistry/bonding-structure-and-properties2026-11-08https://exercises.lol/video-media/aqa_gcse_chemistry/bonding-structure-and-properties/bonding-structure-and-properties.thumb.jpg?v=1794116428Topic 2: Bonding, structure and the properties of matterWhy it matters. One Friday evening in 2004, Andre Geim and Konstantin Novoselov at the University of Manchester pressed sticky tape onto a block of graphite…https://exercises.lol/video-media/aqa_gcse_chemistry/bonding-structure-and-properties/bonding-structure-and-properties.enzh.mp4?v=1794116428-210652026-10-28yes https://exercises.lol/videos/aqa_gcse_chemistry/quantitative-chemistry2026-11-04https://exercises.lol/video-media/aqa_gcse_chemistry/quantitative-chemistry/quantitative-chemistry.thumb.jpg?v=1793790735Topic 3: Quantitative chemistryQuantitative chemistry connects measured mass and volume to particles. Begin with the balanced equation and choose a relation that fits the conditions. Keep…https://exercises.lol/video-media/aqa_gcse_chemistry/quantitative-chemistry/quantitative-chemistry.enzh.mp4?v=1793790735-25802026-10-28yes https://exercises.lol/videos/aqa_gcse_chemistry/chemical-changes2026-11-08https://exercises.lol/video-media/aqa_gcse_chemistry/chemical-changes/chemical-changes.thumb.jpg?v=1794116326Topic 4: Chemical changesWhy it matters. In 1884 the builders of the Washington Monument put a small pyramid of aluminium on its top. It weighed 2.8 kg and was one of the largest…https://exercises.lol/video-media/aqa_gcse_chemistry/chemical-changes/chemical-changes.enzh.mp4?v=1794116326-210602026-10-28yes https://exercises.lol/videos/aqa_gcse_chemistry/energy-changes2026-10-31https://exercises.lol/video-media/aqa_gcse_chemistry/energy-changes/energy-changes.thumb.jpg?v=1793406855Topic 5: Energy changesA temperature change is evidence about an energy transfer. Energy is conserved in both directions. Higher Tier bond calculations and fuel-cell half equations…https://exercises.lol/video-media/aqa_gcse_chemistry/energy-changes/energy-changes.enzh.mp4?v=1793406855-25102026-10-28yes https://exercises.lol/videos/aqa_gcse_chemistry/rate-and-extent2026-11-04https://exercises.lol/video-media/aqa_gcse_chemistry/rate-and-extent/rate-and-extent.thumb.jpg?v=1793790685Topic 6: The rate and extent of chemical changeA fast reaction does not necessarily give a large amount of product. We will measure changes over time, explain them by collisions and then distinguish…https://exercises.lol/video-media/aqa_gcse_chemistry/rate-and-extent/rate-and-extent.enzh.mp4?v=1793790685-25832026-10-28yes https://exercises.lol/videos/aqa_gcse_chemistry/organic-chemistry2026-10-31https://exercises.lol/video-media/aqa_gcse_chemistry/organic-chemistry/organic-chemistry.thumb.jpg?v=1793404919Topic 7: Organic chemistryChoose the process from what happens to the molecules. Heating alone does not tell us which process is taking place. We will connect representations…https://exercises.lol/video-media/aqa_gcse_chemistry/organic-chemistry/organic-chemistry.enzh.mp4?v=1793404919-26612026-10-28yes https://exercises.lol/videos/aqa_gcse_chemistry/chemical-analysis2026-11-08https://exercises.lol/video-media/aqa_gcse_chemistry/chemical-analysis/chemical-analysis.thumb.jpg?v=1794121337Topic 8: Chemical analysisWhy it matters. In October 1858 a sweet-maker in Bradford, England, made a batch of peppermint humbugs. Sugar was expensive, so, like many sweet-makers at the…https://exercises.lol/video-media/aqa_gcse_chemistry/chemical-analysis/chemical-analysis.enzh.mp4?v=1794121337-29652026-10-28yes https://exercises.lol/videos/aqa_gcse_chemistry/chemistry-of-the-atmosphere2026-10-31https://exercises.lol/video-media/aqa_gcse_chemistry/chemistry-of-the-atmosphere/chemistry-of-the-atmosphere.thumb.jpg?v=1793406612Topic 9: Chemistry of the atmosphereA gas may be invisible but still matter. Build each explanation from its source, through the chemical process, to its consequence. Keep a measured value…https://exercises.lol/video-media/aqa_gcse_chemistry/chemistry-of-the-atmosphere/chemistry-of-the-atmosphere.enzh.mp4?v=1793406612-26052026-10-28yes https://exercises.lol/videos/aqa_gcse_chemistry/using-resources2026-10-30https://exercises.lol/video-media/aqa_gcse_chemistry/using-resources/using-resources.thumb.jpg?v=1793364107Topic 10: Using resourcesBegin with the job a material or process must do. A cheap raw material can require expensive treatment. Practical performance needs a supervised record beyond…https://exercises.lol/video-media/aqa_gcse_chemistry/using-resources/using-resources.enzh.mp4?v=1793364107-28102026-10-28yes https://exercises.lol/videos/aqa_gcse_mathematics/topic-012026-10-28https://exercises.lol/video-media/aqa_gcse_mathematics/topic-01/topic-01.thumb.jpg?v=17932213821 · NumberTopic 1 is the number toolkit for everything else. Prime factors give the HCF from the lowest shared powers and the LCM from the highest. The index laws, with…https://exercises.lol/video-media/aqa_gcse_mathematics/topic-01/topic-01.enzh.mp4?v=1793221382-25102026-10-28yes https://exercises.lol/videos/aqa_gcse_mathematics/topic-022026-10-31https://exercises.lol/video-media/aqa_gcse_mathematics/topic-02/topic-02.thumb.jpg?v=1793404863AlgebraThe formulae sheet gives only the quadratic formula. Carry the rest: completing the square shows the turning point; gradient is change in y over change in x…https://exercises.lol/video-media/aqa_gcse_mathematics/topic-02/topic-02.enzh.mp4?v=1793404863-23202026-10-28yes https://exercises.lol/videos/aqa_gcse_mathematics/topic-032026-11-08https://exercises.lol/video-media/aqa_gcse_mathematics/topic-03/topic-03.thumb.jpg?v=1794116671Ratio, proportion and rates of changeWhy it matters. On 23 September 1999 NASA's Mars Climate Orbiter fired its engine to go into orbit around Mars, and was never heard from again. It had flown…https://exercises.lol/video-media/aqa_gcse_mathematics/topic-03/topic-03.enzh.mp4?v=1794116671-210692026-10-28yes https://exercises.lol/videos/aqa_gcse_mathematics/topic-042026-11-08https://exercises.lol/video-media/aqa_gcse_mathematics/topic-04/topic-04.thumb.jpg?v=1794116860Geometry and measuresWhy it matters. In about 240 BC, Eratosthenes, the librarian at Alexandria in Egypt, measured the size of the whole Earth with a stick, a shadow and one…https://exercises.lol/video-media/aqa_gcse_mathematics/topic-04/topic-04.enzh.mp4?v=1794116860-216922026-10-28yes https://exercises.lol/videos/aqa_gcse_mathematics/topic-052026-11-08https://exercises.lol/video-media/aqa_gcse_mathematics/topic-05/topic-05.thumb.jpg?v=1794116675ProbabilityWhy it matters. On 9 September 1990 the writer Marilyn vos Savant answered a reader's puzzle in Parade magazine. On a game show there are three doors: behind…https://exercises.lol/video-media/aqa_gcse_mathematics/topic-05/topic-05.enzh.mp4?v=1794116675-29392026-10-28yes https://exercises.lol/videos/aqa_gcse_mathematics/topic-062026-11-08https://exercises.lol/video-media/aqa_gcse_mathematics/topic-06/topic-06.thumb.jpg?v=1794116280StatisticsWhy it matters. In 1936 the American magazine The Literary Digest ran the biggest opinion poll the world had seen. It posted about 10 million voting cards, got…https://exercises.lol/video-media/aqa_gcse_mathematics/topic-06/topic-06.enzh.mp4?v=1794116280-27222026-10-28yes https://exercises.lol/videos/aqa_gcse_physics/energy2026-10-29https://exercises.lol/video-media/aqa_gcse_physics/energy/energy.thumb.jpg?v=1793308025Topic 1: EnergyTry the motor starter before continuing. Identify what power measures, use the equation, and give the unit. Explain the difference between a rate and an energy…https://exercises.lol/video-media/aqa_gcse_physics/energy/energy.enzh.mp4?v=1793308025-217982026-10-10yes https://exercises.lol/videos/aqa_gcse_physics/particle-model2026-11-08https://exercises.lol/video-media/aqa_gcse_physics/particle-model/particle-model.thumb.jpg?v=1794126329Topic 3: Particle model of matterWhy it matters. In the winter of 1761 to 1762, Joseph Black, a professor of medicine in Glasgow, watched snow and ice melting outside. If melting needed only a…https://exercises.lol/video-media/aqa_gcse_physics/particle-model/particle-model.enzh.mp4?v=1794126329-28962026-10-28yes https://exercises.lol/videos/aqa_gcse_physics/atomic-structure2026-11-08https://exercises.lol/video-media/aqa_gcse_physics/atomic-structure/atomic-structure.thumb.jpg?v=1794125906Topic 4: Atomic structureWhy it matters. In 1909, in a darkened laboratory at the University of Manchester, Hans Geiger and a 20-year-old student, Ernest Marsden, fired alpha particles…https://exercises.lol/video-media/aqa_gcse_physics/atomic-structure/atomic-structure.enzh.mp4?v=1794125906-29442026-10-28yes https://exercises.lol/videos/aqa_gcse_physics/forces2026-11-08https://exercises.lol/video-media/aqa_gcse_physics/forces/forces.thumb.jpg?v=1794126874Topic 5: ForcesWhy it matters. On 2 August 1971, at the end of the third moonwalk of Apollo 15, the commander David Scott stood in front of the television camera holding a…https://exercises.lol/video-media/aqa_gcse_physics/forces/forces.enzh.mp4?v=1794126874-215662026-10-28yes https://exercises.lol/videos/aqa_gcse_physics/waves2026-10-28https://exercises.lol/video-media/aqa_gcse_physics/waves/waves.thumb.jpg?v=1793225165Topic 6: WavesBuild a comparison using paired statements. Sheets 6.1–6.5 develop the models and calculations.https://exercises.lol/video-media/aqa_gcse_physics/waves/waves.enzh.mp4?v=1793225165-213522026-10-28yes https://exercises.lol/videos/aqa_gcse_physics/magnetism2026-10-31https://exercises.lol/video-media/aqa_gcse_physics/magnetism/magnetism.thumb.jpg?v=1793406039Topic 7: Magnetism and electromagnetismFollow the energy transfer and distinguish a potential difference from current in a complete circuit. Sheets 7.1–7.3 build the field models first.https://exercises.lol/video-media/aqa_gcse_physics/magnetism/magnetism.enzh.mp4?v=1793406039-211892026-10-28yes https://exercises.lol/videos/aqa_gcse_physics/space-physics2026-10-28https://exercises.lol/video-media/aqa_gcse_physics/space-physics/space-physics.thumb.jpg?v=1793224042Topic 8: Space physicsUse observations to build explanations. Sheets 8.1–8.3 connect stellar life cycles, orbits and the evidence for expansion.https://exercises.lol/video-media/aqa_gcse_physics/space-physics/space-physics.enzh.mp4?v=1793224042-211112026-10-28yes https://exercises.lol/videos/b1_preliminary/preliminary-reading-notices-and-matching2026-10-31https://exercises.lol/video-media/b1_preliminary/preliminary-reading-notices-and-matching/preliminary-reading-notices-and-matching.thumb.jpg?v=1793409622B1 Preliminary · Reading Parts 1–2: notices and needs matchingB1 Preliminary reading opens with the same two beasts as A2 Key, one level bigger: five notices, and five people matched to eight short texts. Everything from…https://exercises.lol/video-media/b1_preliminary/preliminary-reading-notices-and-matching/preliminary-reading-notices-and-matching.enzh.mp4?v=1793409622-22022026-10-08yes https://exercises.lol/videos/b1_preliminary/preliminary-reading-detailed-meaning-and-cohesion2026-10-30https://exercises.lol/video-media/b1_preliminary/preliminary-reading-detailed-meaning-and-cohesion/preliminary-reading-detailed-meaning-and-cohesion.thumb.jpg?v=1793399183B1 Preliminary · Reading Parts 3–4: detailed meaning and cohesionParts three and four are the long texts. Part three: one text, five four-option questions on detailed meaning. Part four: a text with five sentences removed…https://exercises.lol/video-media/b1_preliminary/preliminary-reading-detailed-meaning-and-cohesion/preliminary-reading-detailed-meaning-and-cohesion.enzh.mp4?v=1793399183-22182026-10-08yes https://exercises.lol/videos/b1_preliminary/preliminary-reading-clozes2026-10-30https://exercises.lol/video-media/b1_preliminary/preliminary-reading-clozes/preliminary-reading-clozes.thumb.jpg?v=1793392244B1 Preliminary · Reading Parts 5–6: lexical and open clozeReading parts five and six are the clozes at B1. Part five: six gaps with four options each, vocabulary and collocation. Part six: six gaps with no options…https://exercises.lol/video-media/b1_preliminary/preliminary-reading-clozes/preliminary-reading-clozes.enzh.mp4?v=1793392244-22032026-10-08yes https://exercises.lol/videos/b1_preliminary/preliminary-writing-responsive-email2026-11-08https://exercises.lol/video-media/b1_preliminary/preliminary-writing-responsive-email/preliminary-writing-responsive-email.thumb.jpg?v=1794115361B1 Preliminary · Writing Part 1: the responsive emailWriting part one is the responsive email, and everyone writes it: about one hundred words, replying to an email, usually from a friend but sometimes from a…https://exercises.lol/video-media/b1_preliminary/preliminary-writing-responsive-email/preliminary-writing-responsive-email.enzh.mp4?v=1794115361-22722026-10-08yes https://exercises.lol/videos/b1_preliminary/preliminary-writing-article-or-story2026-10-30https://exercises.lol/video-media/b1_preliminary/preliminary-writing-article-or-story/preliminary-writing-article-or-story.thumb.jpg?v=1793321773B1 Preliminary · Writing Part 2: article or storyWriting part two gives a choice: an article for a magazine, about one hundred words, or a story starting from a given sentence. The memory hook: the article…https://exercises.lol/video-media/b1_preliminary/preliminary-writing-article-or-story/preliminary-writing-article-or-story.enzh.mp4?v=1793321773-22242026-10-08yes https://exercises.lol/videos/b1_preliminary/preliminary-listening-detail-and-short-extracts2026-10-30https://exercises.lol/video-media/b1_preliminary/preliminary-listening-detail-and-short-extracts/preliminary-listening-detail-and-short-extracts.thumb.jpg?v=1793398890B1 Preliminary · Listening Parts 1–2: detail and short-extract meaningB1 listening opens with short extracts. Part one: seven short recordings, each with three pictures, targeting one detail exactly. Part two: six short…https://exercises.lol/video-media/b1_preliminary/preliminary-listening-detail-and-short-extracts/preliminary-listening-detail-and-short-extracts.enzh.mp4?v=1793398890-22012026-10-08yes https://exercises.lol/videos/b1_preliminary/preliminary-listening-notes-and-interviews2026-10-29https://exercises.lol/video-media/b1_preliminary/preliminary-listening-notes-and-interviews/preliminary-listening-notes-and-interviews.thumb.jpg?v=1793317990B1 Preliminary · Listening Parts 3–4: notes and longer interviewsThe second half of the listening paper. Part three: a talk with six note gaps to fill — a guided tour, a course description. Part four: a longer interview with…https://exercises.lol/video-media/b1_preliminary/preliminary-listening-notes-and-interviews/preliminary-listening-notes-and-interviews.enzh.mp4?v=1793317990-22112026-10-08yes https://exercises.lol/videos/b1_preliminary/preliminary-speaking-description-decision-discussion2026-11-08https://exercises.lol/video-media/b1_preliminary/preliminary-speaking-description-decision-discussion/preliminary-speaking-description-decision-discussion.thumb.jpg?v=1794106282B1 Preliminary · Speaking: description, decision and discussionThe B1 speaking test is ten to twelve minutes with a partner, in four parts. The interview, the photo description, the collaborative decision, and the…https://exercises.lol/video-media/b1_preliminary/preliminary-speaking-description-decision-discussion/preliminary-speaking-description-decision-discussion.enzh.mp4?v=1794106282-22192026-10-08yes https://exercises.lol/videos/code_a_level_cs/nested-loops2026-10-28https://exercises.lol/video-media/code_a_level_cs/nested-loops/nested-loops.thumb.jpg?v=1793201892Nested loopsOne loop inside another sounds simple, and one sentence about it gets misread every year: for every single pass of the outer loop, the inner loop runs all…https://exercises.lol/video-media/code_a_level_cs/nested-loops/nested-loops.enzh.mp4?v=1793201892-21262026-08-23yes https://exercises.lol/videos/code_a_level_cs/files2026-10-28https://exercises.lol/video-media/code_a_level_cs/files/files.thumb.jpg?v=1793184850Text filesOpening a file takes a mode, and the mode is not a formality. Read gives you what is there. Write throws away what was there and starts a fresh file. Append…https://exercises.lol/video-media/code_a_level_cs/files/files.enzh.mp4?v=1793184850-21222026-08-23yes https://exercises.lol/videos/code_a_level_cs/exceptions2026-10-28https://exercises.lol/video-media/code_a_level_cs/exceptions/exceptions.thumb.jpg?v=1793213946ExceptionsAsk Python to turn the word hello into a number and it raises an exception — a value error. And an exception that nobody handles stops the program on the spot…https://exercises.lol/video-media/code_a_level_cs/exceptions/exceptions.enzh.mp4?v=1793213946-21252026-08-23yes https://exercises.lol/videos/code_a_level_cs/stacks2026-10-30https://exercises.lol/video-media/code_a_level_cs/stacks/stacks.thumb.jpg?v=1793319738StacksA stack is the first abstract data type in this course, and the word abstract is doing real work. What defines a stack is its operations: push, pop, peek…https://exercises.lol/video-media/code_a_level_cs/stacks/stacks.enzh.mp4?v=1793319738-21302026-08-23yes https://exercises.lol/videos/code_a_level_cs/queues2026-10-30https://exercises.lol/video-media/code_a_level_cs/queues/queues.thumb.jpg?v=1793338369QueuesA stack hands back what you put in last. That is exactly the wrong thing for anything waiting its turn. A queue is the other ADT, and it behaves like a line of…https://exercises.lol/video-media/code_a_level_cs/queues/queues.enzh.mp4?v=1793338369-21292026-08-22yes https://exercises.lol/videos/code_a_level_cs/linked-lists2026-10-29https://exercises.lol/video-media/code_a_level_cs/linked-lists/linked-lists.thumb.jpg?v=1793234866Linked listsAn array has to know its size before it holds anything, and growing one means copying the lot. A linked list is a chain of nodes, and each node holds two…https://exercises.lol/video-media/code_a_level_cs/linked-lists/linked-lists.enzh.mp4?v=1793234866-21312026-08-23yes https://exercises.lol/videos/code_a_level_cs/searching2026-10-30https://exercises.lol/video-media/code_a_level_cs/searching/searching.thumb.jpg?v=1793326539SearchingFinding a value in a list is the first algorithm anyone writes. It is still taught because the obvious way is the slow one. Searching means finding whether a…https://exercises.lol/video-media/code_a_level_cs/searching/searching.enzh.mp4?v=1793326539-21382026-08-23yes https://exercises.lol/videos/code_a_level_cs/sorting2026-10-30https://exercises.lol/video-media/code_a_level_cs/sorting/sorting.thumb.jpg?v=1793319509SortingBubble sort only ever looks at neighbours. Walk the list and compare each pair in turn, swapping any that are the wrong way round. Watch the five: compared…https://exercises.lol/video-media/code_a_level_cs/sorting/sorting.enzh.mp4?v=1793319509-21212026-08-23yes https://exercises.lol/videos/code_a_level_cs/recursion2026-10-29https://exercises.lol/video-media/code_a_level_cs/recursion/recursion.thumb.jpg?v=1793283733RecursionSome problems shrink into smaller copies of themselves, and a loop is a clumsy way to say so. Recursion is a function that calls itself, and every recursive…https://exercises.lol/video-media/code_a_level_cs/recursion/recursion.enzh.mp4?v=1793283733-21372026-08-23yes https://exercises.lol/videos/code_a_level_cs/classes-objects2026-10-28https://exercises.lol/video-media/code_a_level_cs/classes-objects/classes-objects.thumb.jpg?v=1793178167Classes & objectsSo far you have used types somebody else invented. The moment your problem has a Student in it, none of them fit. A class defines a new kind of thing — a type…https://exercises.lol/video-media/code_a_level_cs/classes-objects/classes-objects.enzh.mp4?v=1793178167-21642026-08-23yes https://exercises.lol/videos/code_a_level_cs/inheritance2026-10-30https://exercises.lol/video-media/code_a_level_cs/inheritance/inheritance.thumb.jpg?v=1793338259Inheritance & encapsulationCopy a class to change one method and you have made a second copy of every bug in it. Inheritance lets a new class start from an existing one instead of from…https://exercises.lol/video-media/code_a_level_cs/inheritance/inheritance.enzh.mp4?v=1793338259-21432026-08-23yes https://exercises.lol/videos/code_a_level_cs/paradigms2026-10-29https://exercises.lol/video-media/code_a_level_cs/paradigms/paradigms.thumb.jpg?v=1793240517Programming paradigmsThe same problem, written twice, can look like two different subjects. That difference has a name, and the exam asks for it. A paradigm is a style of…https://exercises.lol/video-media/code_a_level_cs/paradigms/paradigms.enzh.mp4?v=1793240517-21732026-08-23yes https://exercises.lol/videos/code_a_level_cs/hash-tables2026-10-30https://exercises.lol/video-media/code_a_level_cs/hash-tables/hash-tables.thumb.jpg?v=1793349976Hash tablesA hash table is a list of slots, and the trick is that you never look for anything. You compute where it belongs. Give it the key cat and a function answers…https://exercises.lol/video-media/code_a_level_cs/hash-tables/hash-tables.enzh.mp4?v=1793349976-21602026-08-23yes https://exercises.lol/videos/code_a_level_cs/binary-search-trees2026-10-29https://exercises.lol/video-media/code_a_level_cs/binary-search-trees/binary-search-trees.thumb.jpg?v=1793240481Binary search treesA sorted list is fast to search and slow to change. A tree refuses to choose between the two. A binary search tree keeps values sorted by where it puts them.…https://exercises.lol/video-media/code_a_level_cs/binary-search-trees/binary-search-trees.enzh.mp4?v=1793240481-21662026-08-23yes https://exercises.lol/videos/code_a_level_cs/graphs2026-10-29https://exercises.lol/video-media/code_a_level_cs/graphs/graphs.thumb.jpg?v=1793292228GraphsA road map, a friend list and a network of routers are the same object. Once you see that, one set of algorithms answers all three. A graph is a set of nodes…https://exercises.lol/video-media/code_a_level_cs/graphs/graphs.enzh.mp4?v=1793292228-21412026-08-23yes https://exercises.lol/videos/code_ap_csa/using-objects2026-10-28https://exercises.lol/video-media/code_ap_csa/using-objects/using-objects.thumb.jpg?v=1793184989Using objectsHere is the picture the whole lesson depends on. When you write String greeting equals Hello, the variable does not contain the letters. It holds a reference…https://exercises.lol/video-media/code_ap_csa/using-objects/using-objects.enzh.mp4?v=1793184989-21402026-08-23yes https://exercises.lol/videos/code_ap_csa/selection2026-10-30https://exercises.lol/video-media/code_ap_csa/selection/selection.thumb.jpg?v=1793349877Booleans and selectionA program that always does the same thing is not much of a program. Everything that makes one interesting starts with a single true or false. A relational…https://exercises.lol/video-media/code_ap_csa/selection/selection.enzh.mp4?v=1793349877-21232026-08-23yes https://exercises.lol/videos/code_ap_csa/loops2026-10-30https://exercises.lol/video-media/code_ap_csa/loops/loops.thumb.jpg?v=1793320233Loops in JavaEvery loop, in every language, needs the same three parts, and a while loop spreads them out where you can see them. A start: i is set to one, before the loop.…https://exercises.lol/video-media/code_ap_csa/loops/loops.enzh.mp4?v=1793320233-21112026-08-23yes https://exercises.lol/videos/code_ap_csa/strings-loops2026-10-29https://exercises.lol/video-media/code_ap_csa/strings-loops/strings-loops.thumb.jpg?v=1793275127Strings and nested loopsA String looks like one thing. The moment you need to count something inside it, it becomes a list of characters. To go through a String you loop over its…https://exercises.lol/video-media/code_ap_csa/strings-loops/strings-loops.enzh.mp4?v=1793275127-21112026-08-23yes https://exercises.lol/videos/code_ap_csa/writing-a-class2026-10-27https://exercises.lol/video-media/code_ap_csa/writing-a-class/writing-a-class.thumb.jpg?v=1793140728Writing a classUntil now you have used other people's types. Now you make your own. A class is a blueprint: it says what a Dog HAS — a name and an age. Those are its instance…https://exercises.lol/video-media/code_ap_csa/writing-a-class/writing-a-class.enzh.mp4?v=1793140728-21212026-08-23yes https://exercises.lol/videos/code_ap_csa/arrays2026-10-30https://exercises.lol/video-media/code_ap_csa/arrays/arrays.thumb.jpg?v=1793337627ArraysTwenty test scores and twenty variable names is a mistake waiting to happen. One name and a number is the whole idea. An array holds many values of one type…https://exercises.lol/video-media/code_ap_csa/arrays/arrays.enzh.mp4?v=1793337627-21092026-08-23yes https://exercises.lol/videos/code_ap_csa/array-algorithms2026-10-30https://exercises.lol/video-media/code_ap_csa/array-algorithms/array-algorithms.thumb.jpg?v=1793319860Array algorithmsFour array jobs turn up on nearly every paper, and they are all the same shape. Sum: start at zero and add every value. Count: start at zero and add one, but…https://exercises.lol/video-media/code_ap_csa/array-algorithms/array-algorithms.enzh.mp4?v=1793319860-21282026-08-23yes https://exercises.lol/videos/code_ap_csa/arraylist2026-10-30https://exercises.lol/video-media/code_ap_csa/arraylist/arraylist.thumb.jpg?v=1793319486ArrayListAn array's length is frozen the moment you make it, and often you do not know how many things there will be. That is what ArrayList is for. Watch: names dot…https://exercises.lol/video-media/code_ap_csa/arraylist/arraylist.enzh.mp4?v=1793319486-21232026-08-23yes https://exercises.lol/videos/code_ap_csa/arraylist-algorithms2026-10-28https://exercises.lol/video-media/code_ap_csa/arraylist-algorithms/arraylist-algorithms.thumb.jpg?v=1793197215The remove bugThe safe way to keep only some items is not to remove the others — it is to build a second list. Walk the original, test each value, and the loop copies the…https://exercises.lol/video-media/code_ap_csa/arraylist-algorithms/arraylist-algorithms.enzh.mp4?v=1793197215-21132026-08-23yes https://exercises.lol/videos/code_ap_csa/two-d-arrays2026-10-28https://exercises.lol/video-media/code_ap_csa/two-d-arrays/two-d-arrays.thumb.jpg?v=17932135622-D arraysA seating plan, a chessboard, a spreadsheet - none of them fit in a single row of values. A 2-D array is a grid — really, an array whose items are themselves…https://exercises.lol/video-media/code_ap_csa/two-d-arrays/two-d-arrays.enzh.mp4?v=1793213562-21052026-08-23yes https://exercises.lol/videos/code_ap_csa/searching2026-10-28https://exercises.lol/video-media/code_ap_csa/searching/searching.thumb.jpg?v=1793213876SearchingFinding one item in a list sounds too simple to teach. The exam asks about it because one way looks at a thousand items and the other looks at ten. Linear…https://exercises.lol/video-media/code_ap_csa/searching/searching.enzh.mp4?v=1793213876-21102026-08-23yes https://exercises.lol/videos/code_ap_csa/sorting2026-10-29https://exercises.lol/video-media/code_ap_csa/sorting/sorting.thumb.jpg?v=1793273565SortingYou will not be asked to invent a sort. You will be asked to trace one, which means knowing exactly what it has done after each pass. Selection sort works by…https://exercises.lol/video-media/code_ap_csa/sorting/sorting.enzh.mp4?v=1793273565-21232026-08-23yes https://exercises.lol/videos/code_ap_csa/recursion2026-10-28https://exercises.lol/video-media/code_ap_csa/recursion/recursion.thumb.jpg?v=1793201602RecursionA recursive method is one that calls itself, and every single one has exactly two parts. The base case is the question it can answer directly, with no further…https://exercises.lol/video-media/code_ap_csa/recursion/recursion.enzh.mp4?v=1793201602-21222026-08-23yes https://exercises.lol/videos/code_ap_csa/files2026-10-29https://exercises.lol/video-media/code_ap_csa/files/files.thumb.jpg?v=1793264631Text filesA program that forgets everything the moment it closes is a toy. Writing to a file is the smallest step out of that. PrintWriter writes to a file with the same…https://exercises.lol/video-media/code_ap_csa/files/files.enzh.mp4?v=1793264631-21062026-08-23yes https://exercises.lol/videos/code_ap_csa/inheritance2026-10-30https://exercises.lol/video-media/code_ap_csa/inheritance/inheritance.thumb.jpg?v=1793350180InheritanceTwo classes that share nine methods out of ten give you nine chances to fix a bug in one of them and not the other. Inheritance lets one class build on another…https://exercises.lol/video-media/code_ap_csa/inheritance/inheritance.enzh.mp4?v=1793350180-21262026-08-23yes https://exercises.lol/videos/code_ap_csa/polymorphism2026-10-30https://exercises.lol/video-media/code_ap_csa/polymorphism/polymorphism.thumb.jpg?v=1793319742PolymorphismHere is the idea, and it is worth watching rather than reading. The variable is declared as an Animal, and it points at a Dog. Call a dot speak and you get…https://exercises.lol/video-media/code_ap_csa/polymorphism/polymorphism.enzh.mp4?v=1793319742-21042026-08-23yes https://exercises.lol/videos/code_ap_csp/what-computing-is2026-10-30https://exercises.lol/video-media/code_ap_csp/what-computing-is/what-computing-is.thumb.jpg?v=1793338875What computing isAlmost every program ever written is built from only three ideas, and all three turn up in this lesson. A program is a set of instructions a computer follows…https://exercises.lol/video-media/code_ap_csp/what-computing-is/what-computing-is.enzh.mp4?v=1793338875-21342026-08-23yes https://exercises.lol/videos/code_ap_csp/bits-and-binary2026-10-30https://exercises.lol/video-media/code_ap_csp/bits-and-binary/bits-and-binary.thumb.jpg?v=1793348989Bits and binaryA photograph, a song and this sentence are all the same thing to a computer, and it is a far simpler thing than any of them. A bit is one digit that is either…https://exercises.lol/video-media/code_ap_csp/bits-and-binary/bits-and-binary.enzh.mp4?v=1793348989-21492026-08-23yes https://exercises.lol/videos/code_ap_csp/compression2026-10-28https://exercises.lol/video-media/code_ap_csp/compression/compression.thumb.jpg?v=1793198419Data compressionData costs space to store and time to send, so we compress it — and there are two kinds. Lossless makes a file smaller while keeping every single bit. Follow…https://exercises.lol/video-media/code_ap_csp/compression/compression.enzh.mp4?v=1793198419-21042026-08-23yes https://exercises.lol/videos/code_ap_csp/variables2026-10-30https://exercises.lol/video-media/code_ap_csp/variables/variables.thumb.jpg?v=1793349345Variables and expressionsThe equals sign is about to mean something it has never meant in a maths lesson. A variable stores a value so you can use it later, and the equals sign does…https://exercises.lol/video-media/code_ap_csp/variables/variables.enzh.mp4?v=1793349345-21332026-08-23yes https://exercises.lol/videos/code_ap_csp/lists2026-10-30https://exercises.lol/video-media/code_ap_csp/lists/lists.thumb.jpg?v=1793320205Lists and data abstractionA program often needs many values at once — a whole class of scores. One variable per value gets messy fast, and it does not scale at all. A list holds many…https://exercises.lol/video-media/code_ap_csp/lists/lists.enzh.mp4?v=1793320205-21262026-08-23yes https://exercises.lol/videos/code_ap_csp/selection2026-10-30https://exercises.lol/video-media/code_ap_csp/selection/selection.thumb.jpg?v=1793338033SelectionA program that cannot choose can only ever do one thing, and there is a limit to how useful that is. Selection means the program picks what to do based on a…https://exercises.lol/video-media/code_ap_csp/selection/selection.enzh.mp4?v=1793338033-21322026-08-23yes https://exercises.lol/videos/code_ap_csp/iteration2026-10-30https://exercises.lol/video-media/code_ap_csp/iteration/iteration.thumb.jpg?v=1793338564IterationWriting a line out a hundred times is not the alternative to a loop. Nobody would; the program simply would not get written. Iteration means doing the same…https://exercises.lol/video-media/code_ap_csp/iteration/iteration.enzh.mp4?v=1793338564-21362026-08-23yes https://exercises.lol/videos/code_ap_csp/procedures2026-10-28https://exercises.lol/video-media/code_ap_csp/procedures/procedures.thumb.jpg?v=1793178486Procedures and abstractionThe same eight lines turn up in four places, and then the requirement changes. A procedure is a named block of code you can use again and again. In Python you…https://exercises.lol/video-media/code_ap_csp/procedures/procedures.enzh.mp4?v=1793178486-21152026-08-23yes https://exercises.lol/videos/code_ap_csp/searching2026-10-29https://exercises.lol/video-media/code_ap_csp/searching/searching.thumb.jpg?v=1793240259Algorithms: searchingThere are two ways to find something in a list, and the difference between them is the difference between ten steps and a thousand. An algorithm is a clear…https://exercises.lol/video-media/code_ap_csp/searching/searching.enzh.mp4?v=1793240259-21332026-08-23yes https://exercises.lol/videos/code_ap_csp/randomness2026-10-30https://exercises.lol/video-media/code_ap_csp/randomness/randomness.thumb.jpg?v=1793320350Randomness and simulationSome programs need chance — games, experiments, models of the real world. The random tools live in a module, so you write import random at the top. Then…https://exercises.lol/video-media/code_ap_csp/randomness/randomness.enzh.mp4?v=1793320350-21222026-08-23yes https://exercises.lol/videos/code_ap_csp/efficiency2026-10-30https://exercises.lol/video-media/code_ap_csp/efficiency/efficiency.thumb.jpg?v=1793320148Algorithmic efficiencyTwo programs can both be correct and still take wildly different amounts of time, so we need a way to compare them. We measure an algorithm by how many steps…https://exercises.lol/video-media/code_ap_csp/efficiency/efficiency.enzh.mp4?v=1793320148-21152026-08-23yes https://exercises.lol/videos/code_ap_csp/internet2026-10-30https://exercises.lol/video-media/code_ap_csp/internet/internet.thumb.jpg?v=1793348819The Internet and how data travelsNobody runs the Internet. It is worth sitting with how strange that is before looking at how it works. The Internet is an enormous network of computers joined…https://exercises.lol/video-media/code_ap_csp/internet/internet.enzh.mp4?v=1793348819-21412026-08-23yes https://exercises.lol/videos/code_ap_csp/parallel2026-10-28https://exercises.lol/video-media/code_ap_csp/parallel/parallel.thumb.jpg?v=1793203339Parallel and distributed computingMost simple programs are sequential: step one finishes before step two starts. Easy to follow, but slow for a big job — look at how far that top row runs.…https://exercises.lol/video-media/code_ap_csp/parallel/parallel.enzh.mp4?v=1793203339-21312026-08-23yes https://exercises.lol/videos/code_ap_csp/impact2026-10-28https://exercises.lol/video-media/code_ap_csp/impact/impact.thumb.jpg?v=1793186156Impact of computingEvery innovation in this unit has done real good and real harm, usually to different people. Computing touches almost every part of life, and the same tool…https://exercises.lol/video-media/code_ap_csp/impact/impact.enzh.mp4?v=1793186156-21492026-08-23yes https://exercises.lol/videos/code_c_basics/c-skeleton2026-10-30https://exercises.lol/video-media/code_c_basics/c-skeleton/c-skeleton.thumb.jpg?v=1793321186The C skeletonC works differently from the languages elsewhere on this site, and the difference shapes everything else. You write the source file. Then a compiler reads the…https://exercises.lol/video-media/code_c_basics/c-skeleton/c-skeleton.enzh.mp4?v=1793321186-21492026-08-22yes https://exercises.lol/videos/code_c_basics/types-arithmetic2026-10-30https://exercises.lol/video-media/code_c_basics/types-arithmetic/types-arithmetic.thumb.jpg?v=1793335995Types and arithmeticC will let you divide seven by two and hand you three, with no warning and no error. The type you chose decided that, before the division ever happened. In C…https://exercises.lol/video-media/code_c_basics/types-arithmetic/types-arithmetic.enzh.mp4?v=1793335995-21592026-08-23yes https://exercises.lol/videos/code_c_basics/selection2026-10-28https://exercises.lol/video-media/code_c_basics/selection/selection.thumb.jpg?v=1793207929Selection in CC does not have a true-or-false type the way the other languages here do. Instead it has a rule: zero is false, and everything else — one, forty-two, even…https://exercises.lol/video-media/code_c_basics/selection/selection.enzh.mp4?v=1793207929-21482026-08-23yes https://exercises.lol/videos/code_c_basics/loops2026-10-30https://exercises.lol/video-media/code_c_basics/loops/loops.thumb.jpg?v=1793320569Loops in CC gives you two loops, and for counting they do the same job. The while version puts the start, the test and the step in three separate places, and the day you…https://exercises.lol/video-media/code_c_basics/loops/loops.enzh.mp4?v=1793320569-21302026-08-22yes https://exercises.lol/videos/code_c_basics/functions2026-10-30https://exercises.lol/video-media/code_c_basics/functions/functions.thumb.jpg?v=1793320081Functions in CA C function tells you everything about itself in its first line. It starts with the return type — what comes back — and that is required; you cannot leave it…https://exercises.lol/video-media/code_c_basics/functions/functions.enzh.mp4?v=1793320081-21222026-08-23yes https://exercises.lol/videos/code_c_basics/nested-loops2026-10-30https://exercises.lol/video-media/code_c_basics/nested-loops/nested-loops.thumb.jpg?v=1793320715Nested loopsA loop inside a loop is not complicated, but the order matters and it is easy to get backwards. The outer counter takes one value. Then the inner loop runs all…https://exercises.lol/video-media/code_c_basics/nested-loops/nested-loops.enzh.mp4?v=1793320715-21132026-08-22yes https://exercises.lol/videos/code_c_basics/arrays2026-10-30https://exercises.lol/video-media/code_c_basics/arrays/arrays.thumb.jpg?v=1793337699Arrays in CTwenty temperatures and twenty variable names is twenty chances to type the wrong one. C gives you one name and a number instead. An array is several boxes of…https://exercises.lol/video-media/code_c_basics/arrays/arrays.enzh.mp4?v=1793337699-21582026-08-22yes https://exercises.lol/videos/code_c_basics/pointers2026-10-29https://exercises.lol/video-media/code_c_basics/pointers/pointers.thumb.jpg?v=1793262118PointersTwo lessons ago something odd happened. A function that added one to an int changed nothing outside, because the copy was changed and then thrown away. But a…https://exercises.lol/video-media/code_c_basics/pointers/pointers.enzh.mp4?v=1793262118-21542026-08-22yes https://exercises.lol/videos/code_c_basics/strings2026-10-30https://exercises.lol/video-media/code_c_basics/strings/strings.thumb.jpg?v=1793320841Strings in CC has no string type at all. What it has is an array of char, and everything about strings in this language follows from that. Write the word hi and you get an…https://exercises.lol/video-media/code_c_basics/strings/strings.enzh.mp4?v=1793320841-21482026-08-22yes https://exercises.lol/videos/code_c_basics/array-algorithms2026-10-30https://exercises.lol/video-media/code_c_basics/array-algorithms/array-algorithms.thumb.jpg?v=1793319966Array algorithmsFour jobs come up again and again with arrays, and they look like four different recipes. They are not. Every one of them is the same loop over every item…https://exercises.lol/video-media/code_c_basics/array-algorithms/array-algorithms.enzh.mp4?v=1793319966-21502026-08-22yes https://exercises.lol/videos/code_c_basics/two-d-arrays2026-10-29https://exercises.lol/video-media/code_c_basics/two-d-arrays/two-d-arrays.thumb.jpg?v=1793261693Two-dimensional arraysA seating plan, a chessboard, a month of temperatures for six cities — these are grids, and one index is not enough for them. So C lets you write two. This…https://exercises.lol/video-media/code_c_basics/two-d-arrays/two-d-arrays.enzh.mp4?v=1793261693-21452026-08-23yes https://exercises.lol/videos/code_c_basics/searching2026-10-30https://exercises.lol/video-media/code_c_basics/searching/searching.thumb.jpg?v=1793320704SearchingYou met this one last lesson. Linear search checks the items one after another, from the front, and returns the index as soon as one matches. If the loop runs…https://exercises.lol/video-media/code_c_basics/searching/searching.enzh.mp4?v=1793320704-21502026-08-23yes https://exercises.lol/videos/code_c_basics/sorting2026-10-29https://exercises.lol/video-media/code_c_basics/sorting/sorting.thumb.jpg?v=1793290013SortingEvery sort in this lesson is built on one small move: exchanging two items. And you cannot do it in two lines, because a box only holds one thing. You have to…https://exercises.lol/video-media/code_c_basics/sorting/sorting.enzh.mp4?v=1793290013-21482026-08-23yes https://exercises.lol/videos/code_c_basics/recursion2026-10-30https://exercises.lol/video-media/code_c_basics/recursion/recursion.thumb.jpg?v=1793320383RecursionA recursive function is one that calls itself, and every single one has the same two parts. The base case: the smallest version of the problem, which you can…https://exercises.lol/video-media/code_c_basics/recursion/recursion.enzh.mp4?v=1793320383-21472026-08-23yes https://exercises.lol/videos/code_c_basics/structs2026-10-28https://exercises.lol/video-media/code_c_basics/structs/structs.thumb.jpg?v=1793203197StructsSome values belong together. A point is an x and a y; a rectangle is a width and a height. You can keep them in separate variables, but three points means six…https://exercises.lol/video-media/code_c_basics/structs/structs.enzh.mp4?v=1793203197-21432026-08-22yes https://exercises.lol/videos/code_c_basics/dynamic-memory2026-10-30https://exercises.lol/video-media/code_c_basics/dynamic-memory/dynamic-memory.thumb.jpg?v=1793319727Dynamic memoryEvery local variable you have written so far lives on the stack. It appears when the function starts and vanishes when it returns, which is usually exactly…https://exercises.lol/video-media/code_c_basics/dynamic-memory/dynamic-memory.enzh.mp4?v=1793319727-21452026-08-23yes https://exercises.lol/videos/code_c_basics/linked-lists2026-10-30https://exercises.lol/video-media/code_c_basics/linked-lists/linked-lists.thumb.jpg?v=1793320458Linked listsAn array is one solid block. A linked list is the opposite: small structs called nodes, scattered anywhere in the heap, each one holding a value and a pointer…https://exercises.lol/video-media/code_c_basics/linked-lists/linked-lists.enzh.mp4?v=1793320458-21402026-08-22yes https://exercises.lol/videos/code_c_basics/stacks-queues2026-10-30https://exercises.lol/video-media/code_c_basics/stacks-queues/stacks-queues.thumb.jpg?v=1793350676Stacks and queuesThe order you take things out is not a detail. It is the whole difference between an undo button and a print queue. A stack and a queue both hold a line of…https://exercises.lol/video-media/code_c_basics/stacks-queues/stacks-queues.enzh.mp4?v=1793350676-21492026-08-23yes https://exercises.lol/videos/code_c_basics/text-files2026-10-30https://exercises.lol/video-media/code_c_basics/text-files/text-files.thumb.jpg?v=1793320749Text filesEverything you have written so far lives entirely in memory, so when the program ends, all of it disappears with it. A file is different. It sits on disk, and…https://exercises.lol/video-media/code_c_basics/text-files/text-files.enzh.mp4?v=1793320749-21502026-08-23yes https://exercises.lol/videos/code_c_basics/error-handling2026-10-30https://exercises.lol/video-media/code_c_basics/error-handling/error-handling.thumb.jpg?v=1793320934Error handlingIn many languages, a function that cannot do its job will throw an exception, and somewhere up the call chain someone catches it. C has nothing of the kind. A…https://exercises.lol/video-media/code_c_basics/error-handling/error-handling.enzh.mp4?v=1793320934-21392026-08-22yes https://exercises.lol/videos/code_c_basics/bits2026-10-30https://exercises.lol/video-media/code_c_basics/bits/bits.thumb.jpg?v=1793321058Bits and binaryInside the machine an int is not a decimal number; it is a row of bits, each one a nought or a one. Reading it works exactly like ordinary place value, except…https://exercises.lol/video-media/code_c_basics/bits/bits.enzh.mp4?v=1793321058-21502026-08-23yes https://exercises.lol/videos/code_c_basics/run-length-encoding2026-10-29https://exercises.lol/video-media/code_c_basics/run-length-encoding/run-length-encoding.thumb.jpg?v=1793269188Run-length encodingA screenshot of this page is mostly one colour, repeated. Storing that colour ten thousand times over is the waste every compression method starts from.…https://exercises.lol/video-media/code_c_basics/run-length-encoding/run-length-encoding.enzh.mp4?v=1793269188-21472026-08-22yes https://exercises.lol/videos/code_c_basics/preprocessor2026-10-30https://exercises.lol/video-media/code_c_basics/preprocessor/preprocessor.thumb.jpg?v=1793320736Before the compilerSomething runs before the compiler ever sees your file. It is called the preprocessor, and it handles every line beginning with a hash. You have used it since…https://exercises.lol/video-media/code_c_basics/preprocessor/preprocessor.enzh.mp4?v=1793320736-21502026-08-23yes https://exercises.lol/videos/code_cyber_security/security-privacy2026-10-30https://exercises.lol/video-media/code_cyber_security/security-privacy/security-privacy.thumb.jpg?v=1793320983Security, privacy and integrityThree words get used as if they meant the same thing, and the exam asks you to separate them. Security is about keeping data and systems safe from people who…https://exercises.lol/video-media/code_cyber_security/security-privacy/security-privacy.enzh.mp4?v=1793320983-21282026-08-23yes https://exercises.lol/videos/code_cyber_security/malware2026-10-28https://exercises.lol/video-media/code_cyber_security/malware/malware.thumb.jpg?v=1793210251MalwareMalware is any program written to harm a computer or steal from it, and the exam names six kinds. Six names is a list to memorise unless you group them. Group…https://exercises.lol/video-media/code_cyber_security/malware/malware.enzh.mp4?v=1793210251-21292026-08-23yes https://exercises.lol/videos/code_cyber_security/attacks2026-10-30https://exercises.lol/video-media/code_cyber_security/attacks/attacks.thumb.jpg?v=1793321306Attacks and brute forceBeyond malware, attackers go at a system directly. A brute-force attack tries every possible password until one works — no cleverness, just patience and a fast…https://exercises.lol/video-media/code_cyber_security/attacks/attacks.enzh.mp4?v=1793321306-21252026-08-23yes https://exercises.lol/videos/code_cyber_security/social2026-10-30https://exercises.lol/video-media/code_cyber_security/social/social.thumb.jpg?v=1793320683Social engineeringEverything so far has attacked the machine. But the weakest part of a system is usually not the machine — it is a person, who can simply be asked. Social…https://exercises.lol/video-media/code_cyber_security/social/social.enzh.mp4?v=1793320683-21202026-08-23yes https://exercises.lol/videos/code_cyber_security/defences2026-10-30https://exercises.lol/video-media/code_cyber_security/defences/defences.thumb.jpg?v=1793320242Defending a systemDefences are usually given as a list, and that hides the point. Draw them as rings instead. An attacker coming from outside meets one wall after another: the…https://exercises.lol/video-media/code_cyber_security/defences/defences.enzh.mp4?v=1793320242-21232026-08-23yes https://exercises.lol/videos/code_cyber_security/authentication2026-10-30https://exercises.lol/video-media/code_cyber_security/authentication/authentication.thumb.jpg?v=1793333188Passwords and authenticationA password proves that somebody knows a password. Getting from there to proving they are who they say they are is the whole problem. Authentication means…https://exercises.lol/video-media/code_cyber_security/authentication/authentication.enzh.mp4?v=1793333188-21252026-08-23yes https://exercises.lol/videos/code_cyber_security/hashing2026-10-28https://exercises.lol/video-media/code_cyber_security/hashing/hashing.thumb.jpg?v=1793198252Storing passwords safelyStart with what must never happen. If a site stores passwords as plain text and is breached, every password is readable the moment the file leaves the…https://exercises.lol/video-media/code_cyber_security/hashing/hashing.enzh.mp4?v=1793198252-21282026-08-23yes https://exercises.lol/videos/code_cyber_security/encoding2026-10-30https://exercises.lol/video-media/code_cyber_security/encoding/encoding.thumb.jpg?v=1793321386Encoding is not encryptionPeople say "encoded" when they mean "encrypted", and the two are not the same thing. Encoding changes the FORMAT of data so it can be stored or sent. It is not…https://exercises.lol/video-media/code_cyber_security/encoding/encoding.enzh.mp4?v=1793321386-21022026-08-23yes https://exercises.lol/videos/code_cyber_security/symmetric2026-10-30https://exercises.lol/video-media/code_cyber_security/symmetric/symmetric.thumb.jpg?v=1793349075Symmetric encryptionScrambling a message is the easy half. The hard half is that whoever unscrambles it needs something you would rather nobody else had. Encryption scrambles a…https://exercises.lol/video-media/code_cyber_security/symmetric/symmetric.enzh.mp4?v=1793349075-21272026-08-23yes https://exercises.lol/videos/code_cyber_security/asymmetric2026-10-28https://exercises.lol/video-media/code_cyber_security/asymmetric/asymmetric.thumb.jpg?v=1793209903Asymmetric encryptionLast lesson ended on a problem: you must share the secret key first. Asymmetric encryption answers it by using two keys instead of one. There is a public key…https://exercises.lol/video-media/code_cyber_security/asymmetric/asymmetric.enzh.mp4?v=1793209903-21272026-08-23yes https://exercises.lol/videos/code_cyber_security/signatures2026-10-30https://exercises.lol/video-media/code_cyber_security/signatures/signatures.thumb.jpg?v=1793321076Hashing and digital signaturesIn lesson seven we hashed passwords for secrecy. The same function does a second job: it protects integrity, which means proving that data was not changed.…https://exercises.lol/video-media/code_cyber_security/signatures/signatures.enzh.mp4?v=1793321076-2932026-08-23yes https://exercises.lol/videos/code_cyber_security/https2026-10-30https://exercises.lol/video-media/code_cyber_security/https/https.thumb.jpg?v=1793321061HTTPS, TLS and certificatesStart with something you look at every day. When the address begins with H T T P S and a padlock appears, your connection to that site is encrypted — nobody…https://exercises.lol/video-media/code_cyber_security/https/https.enzh.mp4?v=1793321061-21252026-08-23yes https://exercises.lol/videos/code_cyber_security/integrity2026-10-30https://exercises.lol/video-media/code_cyber_security/integrity/integrity.thumb.jpg?v=1793337815Data integritySecrecy is not the only thing that can fail. A message nobody managed to read can still arrive changed. Integrity means data stays accurate, and two techniques…https://exercises.lol/video-media/code_cyber_security/integrity/integrity.enzh.mp4?v=1793337815-2942026-08-23yes https://exercises.lol/videos/code_cyber_security/sql-injection2026-10-27https://exercises.lol/video-media/code_cyber_security/sql-injection/sql-injection.thumb.jpg?v=1793125736SQL injectionMost apps look up a user by building a query out of a string. You type your name into a box, and the app glues what you typed into the query. Type Mei, and the…https://exercises.lol/video-media/code_cyber_security/sql-injection/sql-injection.enzh.mp4?v=1793125736-21182026-08-23yes https://exercises.lol/videos/code_cyber_security/least-privilege2026-10-28https://exercises.lol/video-media/code_cyber_security/least-privilege/least-privilege.thumb.jpg?v=1793227118Access control and least privilegeMost breaches are not somebody breaking in. They are somebody already inside, reaching further than their job ever needed. Least privilege says: give every…https://exercises.lol/video-media/code_cyber_security/least-privilege/least-privilege.enzh.mp4?v=1793227118-21182026-08-23yes https://exercises.lol/videos/code_cyber_security/ethics2026-10-30https://exercises.lol/video-media/code_cyber_security/ethics/ethics.thumb.jpg?v=1793320704Ethics, law and staying safeYou have spent fifteen lessons learning how attacks work, and that knowledge comes with a duty. A computing professional uses these skills to protect people…https://exercises.lol/video-media/code_cyber_security/ethics/ethics.enzh.mp4?v=1793320704-21332026-08-23yes https://exercises.lol/videos/code_igcse_cs/sequence-io2026-10-30https://exercises.lol/video-media/code_igcse_cs/sequence-io/sequence-io.thumb.jpg?v=1793322069Sequence, input, outputThe syllabus starts with a word that sounds too simple to need naming: sequence. A program is a list of steps, and Python runs them from the top down, one at a…https://exercises.lol/video-media/code_igcse_cs/sequence-io/sequence-io.enzh.mp4?v=1793322069-21202026-08-23yes https://exercises.lol/videos/code_igcse_cs/variables-types2026-10-29https://exercises.lol/video-media/code_igcse_cs/variables-types/variables-types.thumb.jpg?v=1793305935Variables and typesAsk for someone's age and you get back the text seven, not the number seven. That difference is about to cost you an answer. A variable is a named box that…https://exercises.lol/video-media/code_igcse_cs/variables-types/variables-types.enzh.mp4?v=1793305935-21412026-08-23yes https://exercises.lol/videos/code_igcse_cs/selection2026-10-29https://exercises.lol/video-media/code_igcse_cs/selection/selection.thumb.jpg?v=1793291959SelectionA program that runs the same steps every time cannot react to anything. One test is all it takes to change that. Selection is the second big idea in the…https://exercises.lol/video-media/code_igcse_cs/selection/selection.enzh.mp4?v=1793291959-21372026-08-23yes https://exercises.lol/videos/code_igcse_cs/iteration2026-10-30https://exercises.lol/video-media/code_igcse_cs/iteration/iteration.thumb.jpg?v=1793321274IterationWrite the same line ten times and the eleventh will break you. That is what a loop is for. Iteration means repeating steps, and the everyday loop is the one…https://exercises.lol/video-media/code_igcse_cs/iteration/iteration.enzh.mp4?v=1793321274-21382026-08-23yes https://exercises.lol/videos/code_igcse_cs/totalling2026-10-28https://exercises.lol/video-media/code_igcse_cs/totalling/totalling.thumb.jpg?v=1793197137Totalling and countingAdding up a list sounds like nothing, but every mark scheme in this section turns on getting the starting value right. Adding up a list of numbers has a name…https://exercises.lol/video-media/code_igcse_cs/totalling/totalling.enzh.mp4?v=1793197137-21332026-08-23yes https://exercises.lol/videos/code_igcse_cs/procedures2026-10-29https://exercises.lol/video-media/code_igcse_cs/procedures/procedures.thumb.jpg?v=1793292547Procedures and functionsThe same six lines in three places is three places to change when the rule changes, and you will forget one. A function is a named block of code. You write it…https://exercises.lol/video-media/code_igcse_cs/procedures/procedures.enzh.mp4?v=1793292547-21402026-08-23yes https://exercises.lol/videos/code_igcse_cs/validation2026-10-30https://exercises.lol/video-media/code_igcse_cs/validation/validation.thumb.jpg?v=1793338469ValidationWhatever you ask for, someone will type something else. An age of forty-five is fine. An age of nine hundred is not, and neither is a negative age — but the…https://exercises.lol/video-media/code_igcse_cs/validation/validation.enzh.mp4?v=1793338469-21402026-08-23yes https://exercises.lol/videos/code_igcse_cs/arrays2026-10-29https://exercises.lol/video-media/code_igcse_cs/arrays/arrays.thumb.jpg?v=1793305153ArraysSuppose you have three scores. You could use three variables — but then thirty scores needs thirty names, and you cannot write a loop over names. An array…https://exercises.lol/video-media/code_igcse_cs/arrays/arrays.enzh.mp4?v=1793305153-21322026-08-23yes https://exercises.lol/videos/code_igcse_cs/two-d-arrays2026-10-29https://exercises.lol/video-media/code_igcse_cs/two-d-arrays/two-d-arrays.thumb.jpg?v=1793260305Two-dimensional arraysA table of marks, a seating plan, a game board — these have rows and columns, and one index is not enough. A two-dimensional array is a list of lists: each…https://exercises.lol/video-media/code_igcse_cs/two-d-arrays/two-d-arrays.enzh.mp4?v=1793260305-21232026-08-23yes https://exercises.lol/videos/code_igcse_cs/searching2026-10-28https://exercises.lol/video-media/code_igcse_cs/searching/searching.thumb.jpg?v=1793197264Searching, max and minThe obvious way to find something in a list is also the slow way, and the exam wants you to know both. A linear search looks at each item in turn until it…https://exercises.lol/video-media/code_igcse_cs/searching/searching.enzh.mp4?v=1793197264-21332026-08-23yes https://exercises.lol/videos/code_igcse_cs/bubble-sort2026-10-29https://exercises.lol/video-media/code_igcse_cs/bubble-sort/bubble-sort.thumb.jpg?v=1793292494Bubble sortEvery sort is built on one move: exchanging two values. Python has a shortcut that does it in a single line. The exam does not, and wants three lines and a…https://exercises.lol/video-media/code_igcse_cs/bubble-sort/bubble-sort.enzh.mp4?v=1793292494-21222026-08-23yes https://exercises.lol/videos/code_igcse_cs/files2026-10-30https://exercises.lol/video-media/code_igcse_cs/files/files.thumb.jpg?v=1793321319Text filesVariables vanish when a program ends; a file does not. Working with one always takes three steps, and the exam expects all three. Open the file, naming it and…https://exercises.lol/video-media/code_igcse_cs/files/files.enzh.mp4?v=1793321319-21282026-08-23yes https://exercises.lol/videos/code_igcse_cs/sql2026-10-28https://exercises.lol/video-media/code_igcse_cs/sql/sql.thumb.jpg?v=1793177334Databases and SQLYou have been storing data in variables that vanish the moment the program ends. A database is where it stays. A database keeps data in tables, and a table…https://exercises.lol/video-media/code_igcse_cs/sql/sql.enzh.mp4?v=1793177334-21362026-08-23yes https://exercises.lol/videos/code_igcse_cs/logic2026-10-30https://exercises.lol/video-media/code_igcse_cs/logic/logic.thumb.jpg?v=1793349231Boolean logicTwo conditions, and the difference between AND and OR is a mark. Get it backwards and the program runs perfectly and answers wrongly. A Boolean value is either…https://exercises.lol/video-media/code_igcse_cs/logic/logic.enzh.mp4?v=1793349231-21422026-08-23yes https://exercises.lol/videos/code_javascript/console-log2026-10-30https://exercises.lol/video-media/code_javascript/console-log/console-log.thumb.jpg?v=1793321982console.log and commentsJavaScript is the language your browser already speaks. It runs inside the page you are looking at — no installing, no setting up, it is simply there. And the…https://exercises.lol/video-media/code_javascript/console-log/console-log.enzh.mp4?v=1793321982-21572026-08-23yes https://exercises.lol/videos/code_javascript/variables2026-10-30https://exercises.lol/video-media/code_javascript/variables/variables.thumb.jpg?v=1793349635Variables — let and constA program that cannot remember anything can only ever be one line long. A variable is a box with a name on it. This line makes a box called city and puts the…https://exercises.lol/video-media/code_javascript/variables/variables.enzh.mp4?v=1793349635-21442026-08-23yes https://exercises.lol/videos/code_javascript/numbers2026-10-30https://exercises.lol/video-media/code_javascript/numbers/numbers.thumb.jpg?v=1793321504Numbers and mathsJavaScript does arithmetic without being taught. Plus and minus and star add, subtract, multiply — and the answers come straight back in the console. Then look…https://exercises.lol/video-media/code_javascript/numbers/numbers.enzh.mp4?v=1793321504-21272026-08-23yes https://exercises.lol/videos/code_javascript/strings2026-10-27https://exercises.lol/video-media/code_javascript/strings/strings.thumb.jpg?v=1793141798StringsNumbers you can add. Text you cannot - and joining it turns out to be its own small skill. A string is text in quotes, and a plus between two strings joins…https://exercises.lol/video-media/code_javascript/strings/strings.enzh.mp4?v=1793141798-21592026-08-23yes https://exercises.lol/videos/code_javascript/template-literals2026-10-30https://exercises.lol/video-media/code_javascript/template-literals/template-literals.thumb.jpg?v=1793321627Template literalsYou already know how to build a sentence out of pieces: joining with pluses. It works, and it gets ugly fast — four fragments, two pluses, quotes opening and…https://exercises.lol/video-media/code_javascript/template-literals/template-literals.enzh.mp4?v=1793321627-21422026-08-23yes https://exercises.lol/videos/code_javascript/booleans2026-10-30https://exercises.lol/video-media/code_javascript/booleans/booleans.thumb.jpg?v=1793321864Booleans and comparisonsSo far your values have been numbers and strings. Here is a third kind, and it has only two values in the whole world: true and false. It is called a boolean…https://exercises.lol/video-media/code_javascript/booleans/booleans.enzh.mp4?v=1793321864-21482026-08-23yes https://exercises.lol/videos/code_javascript/if-else2026-10-28https://exercises.lol/video-media/code_javascript/if-else/if-else.thumb.jpg?v=1793177318if / elseSo far every line you wrote ran. Nothing in your programs has been able to decide not to. An if in JavaScript has a shape you copy exactly. The word if, then…https://exercises.lol/video-media/code_javascript/if-else/if-else.enzh.mp4?v=1793177318-21452026-08-23yes https://exercises.lol/videos/code_javascript/for-loops2026-10-30https://exercises.lol/video-media/code_javascript/for-loops/for-loops.thumb.jpg?v=1793320706for loopsA JavaScript for loop packs three separate jobs into one set of brackets, separated by two semicolons. The first part sets the counter up, and it runs once…https://exercises.lol/video-media/code_javascript/for-loops/for-loops.enzh.mp4?v=1793320706-21532026-08-23yes https://exercises.lol/videos/code_javascript/while-loops2026-10-30https://exercises.lol/video-media/code_javascript/while-loops/while-loops.thumb.jpg?v=1793321911while loopsA for loop is right when the number of passes is written down in the loop itself — one to five is five passes, and you can see it. But now suppose you start at…https://exercises.lol/video-media/code_javascript/while-loops/while-loops.enzh.mp4?v=1793321911-21452026-08-23yes https://exercises.lol/videos/code_javascript/functions2026-10-30https://exercises.lol/video-media/code_javascript/functions/functions.thumb.jpg?v=1793349369FunctionsYou have written the same three lines twice already, and this page is only going to get longer. A function is a job with a name. You write the word function…https://exercises.lol/video-media/code_javascript/functions/functions.enzh.mp4?v=1793349369-21442026-08-23yes https://exercises.lol/videos/code_javascript/arrow-functions2026-10-28https://exercises.lol/video-media/code_javascript/arrow-functions/arrow-functions.thumb.jpg?v=1793209901Arrow functionsStart with the function you already know how to write. First, give the function a name by storing it in a const, instead of naming it after the word function.…https://exercises.lol/video-media/code_javascript/arrow-functions/arrow-functions.enzh.mp4?v=1793209901-21162026-08-23yes https://exercises.lol/videos/code_javascript/arrays2026-10-28https://exercises.lol/video-media/code_javascript/arrays/arrays.thumb.jpg?v=1793178439ArraysYou can hold one score in a variable. Holding a whole class of them needs something that counts. An array holds several values in order, under one name…https://exercises.lol/video-media/code_javascript/arrays/arrays.enzh.mp4?v=1793178439-21472026-08-23yes https://exercises.lol/videos/code_javascript/array-methods2026-10-30https://exercises.lol/video-media/code_javascript/array-methods/array-methods.thumb.jpg?v=1793321505Array methodsDoubling every number in an array is something you can already do: make an empty array, write the loop yourself, push each doubled value. Four lines, an index…https://exercises.lol/video-media/code_javascript/array-methods/array-methods.enzh.mp4?v=1793321505-21332026-08-23yes https://exercises.lol/videos/code_javascript/objects2026-10-30https://exercises.lol/video-media/code_javascript/objects/objects.thumb.jpg?v=1793321505ObjectsAn array holds a list of similar things. An object holds different facts about ONE thing. You could keep a book's title and page count in two separate…https://exercises.lol/video-media/code_javascript/objects/objects.enzh.mp4?v=1793321505-21372026-08-23yes https://exercises.lol/videos/code_javascript/putting-it-together2026-10-30https://exercises.lol/video-media/code_javascript/putting-it-together/putting-it-together.thumb.jpg?v=1793321689Putting it togetherOne more loop before the end, and it is the one you will reach for most. The version you know needs a counter and an index — three things to write, and an…https://exercises.lol/video-media/code_javascript/putting-it-together/putting-it-together.enzh.mp4?v=1793321689-21242026-08-23yes https://exercises.lol/videos/code_latex/first-document2026-10-28https://exercises.lol/video-media/code_latex/first-document/first-document.thumb.jpg?v=1793213793Your first documentEvery document you have made before this argued with you about how it looks - you nudge a box and the picture jumps, you set a heading and the size is wrong.…https://exercises.lol/video-media/code_latex/first-document/first-document.enzh.mp4?v=1793213793-21332026-08-23yes https://exercises.lol/videos/code_latex/sections2026-10-29https://exercises.lol/video-media/code_latex/sections/sections.thumb.jpg?v=1793236252Sections and titlesNumber your headings by hand and you will renumber them by hand, every time you add one. Real documents are split into sections so a reader can follow them…https://exercises.lol/video-media/code_latex/sections/sections.enzh.mp4?v=1793236252-21272026-08-23yes https://exercises.lol/videos/code_latex/emphasis2026-10-28https://exercises.lol/video-media/code_latex/emphasis/emphasis.thumb.jpg?v=1793184702Bold, italic and emphasisYou have been writing one shape since lesson one - a backslash, a name, a pair of braces. Here it earns its keep three times over. To change how a word looks…https://exercises.lol/video-media/code_latex/emphasis/emphasis.enzh.mp4?v=1793184702-21492026-08-23yes https://exercises.lol/videos/code_latex/lists2026-10-28https://exercises.lol/video-media/code_latex/lists/lists.thumb.jpg?v=1793227764Bulleted and numbered listsSo far every LaTeX idea has been a command. There is a second shape, and the rest of this course is built on it. A list is your first ENVIRONMENT, which is the…https://exercises.lol/video-media/code_latex/lists/lists.enzh.mp4?v=1793227764-21252026-08-23yes https://exercises.lol/videos/code_latex/maths2026-10-30https://exercises.lol/video-media/code_latex/maths/maths.thumb.jpg?v=1793321752Maths — your first formulaThis is what LaTeX is famous for. Put dollar signs around something and everything between them is set as MATHS. Look at what changes: the letters lean, the…https://exercises.lol/video-media/code_latex/maths/maths.enzh.mp4?v=1793321752-21182026-08-23yes https://exercises.lol/videos/code_latex/amsmath2026-10-30https://exercises.lol/video-media/code_latex/amsmath/amsmath.thumb.jpg?v=1793321056Fractions, roots and sumsBefore the maths, one new idea: a package. A package adds commands LaTeX does not have on its own, and you load it in the preamble with usepackage. Amsmath is…https://exercises.lol/video-media/code_latex/amsmath/amsmath.enzh.mp4?v=1793321056-21182026-08-23yes https://exercises.lol/videos/code_latex/align2026-10-30https://exercises.lol/video-media/code_latex/align/align.thumb.jpg?v=1793321949Aligning equationsWhen you show working, a reader follows it by the equals signs. Set each line as its own equation and they scatter. Line them up instead and the eye runs…https://exercises.lol/video-media/code_latex/align/align.enzh.mp4?v=1793321949-21142026-08-23yes https://exercises.lol/videos/code_latex/tables2026-10-30https://exercises.lol/video-media/code_latex/tables/tables.thumb.jpg?v=1793332112TablesEvery environment so far has just needed its name. This one asks you a question before it will draw anything. A table is the tabular environment, and it takes…https://exercises.lol/video-media/code_latex/tables/tables.enzh.mp4?v=1793332112-21272026-08-23yes https://exercises.lol/videos/code_latex/tikz2026-10-29https://exercises.lol/video-media/code_latex/tikz/tikz.thumb.jpg?v=1793291715Drawing with TikZA diagram in a LaTeX document is not a picture you made somewhere else and pasted in. You write it, in the same file, in the shapes you already know. You can…https://exercises.lol/video-media/code_latex/tikz/tikz.enzh.mp4?v=1793291715-21342026-08-23yes https://exercises.lol/videos/code_latex/refs2026-10-28https://exercises.lol/video-media/code_latex/refs/refs.thumb.jpg?v=1793214943Labels and cross-referencesLesson two showed headings renumbering themselves, and left a gap. Here it is. The sentence says "as shown in Section 2". Add a section above Methods and…https://exercises.lol/video-media/code_latex/refs/refs.enzh.mp4?v=1793214943-21242026-08-23yes https://exercises.lol/videos/code_latex/citations2026-10-30https://exercises.lol/video-media/code_latex/citations/citations.thumb.jpg?v=1793339723Citations and bibliographyCopy one reference by hand into twenty places and one of them will be wrong. LaTeX never copies it twice. Academic writing has to say where facts came from…https://exercises.lol/video-media/code_latex/citations/citations.enzh.mp4?v=1793339723-21242026-08-23yes https://exercises.lol/videos/code_latex/geometry2026-10-28https://exercises.lol/video-media/code_latex/geometry/geometry.thumb.jpg?v=1793200291Page layout and marginsBefore the command, the shape. The outer rectangle is the paper. The lines inside it are the text block — where words are allowed to go. And the gap between…https://exercises.lol/video-media/code_latex/geometry/geometry.enzh.mp4?v=1793200291-21132026-08-23yes https://exercises.lol/videos/code_latex/colour2026-10-29https://exercises.lol/video-media/code_latex/colour/colour.thumb.jpg?v=1793268548Colour and linksNothing new happens in this lesson, and that is the point - you already know the shape colour uses. Colour comes from the xcolor package. Load it in the…https://exercises.lol/video-media/code_latex/colour/colour.enzh.mp4?v=1793268548-21262026-08-23yes https://exercises.lol/videos/code_latex/report2026-10-30https://exercises.lol/video-media/code_latex/report/report.thumb.jpg?v=1793321343Capstone: a one-page reportLook at what thirteen lessons have given you. Section, for structure that numbers itself. Textbf and emph, for the way words look. Dollars and frac, for the…https://exercises.lol/video-media/code_latex/report/report.enzh.mp4?v=1793321343-21222026-08-23yes https://exercises.lol/videos/code_linux/prompt2026-10-30https://exercises.lol/video-media/code_linux/prompt/prompt.thumb.jpg?v=1793375559The shell and the promptThere are no icons here and nothing to click. Everything you are about to do, you do by typing its name. When the terminal is ready it shows a prompt and…https://exercises.lol/video-media/code_linux/prompt/prompt.enzh.mp4?v=1793375559-21282026-08-23yes https://exercises.lol/videos/code_linux/moving2026-10-29https://exercises.lol/video-media/code_linux/moving/moving.thumb.jpg?v=1793265912Moving aroundA graphical file manager shows you where you are. Here nothing does, so the first skill is knowing. Folders — Linux calls them directories — hold files and…https://exercises.lol/video-media/code_linux/moving/moving.enzh.mp4?v=1793265912-21362026-08-23yes https://exercises.lol/videos/code_linux/reading2026-10-30https://exercises.lol/video-media/code_linux/reading/reading.thumb.jpg?v=1793335721Reading filesOpening a file to look at it should not need an application, and on the command line it does not. The simplest way to read a file is c a t, which prints the…https://exercises.lol/video-media/code_linux/reading/reading.enzh.mp4?v=1793335721-21212026-08-23yes https://exercises.lol/videos/code_linux/creating2026-10-30https://exercises.lol/video-media/code_linux/creating/creating.thumb.jpg?v=1793335372Creating and removingYou cannot right-click and choose New Folder. Two commands do the whole job, and they are short. Two commands make things. M k d i r makes a directory — a…https://exercises.lol/video-media/code_linux/creating/creating.enzh.mp4?v=1793335372-21582026-08-23yes https://exercises.lol/videos/code_linux/wildcards2026-10-29https://exercises.lol/video-media/code_linux/wildcards/wildcards.thumb.jpg?v=1793292015WildcardsYou have twenty photographs to rename and you are not going to type twenty names. A wildcard is a symbol that stands for "anything", and it turns one command…https://exercises.lol/video-media/code_linux/wildcards/wildcards.enzh.mp4?v=1793292015-21302026-08-23yes https://exercises.lol/videos/code_linux/redirection2026-10-29https://exercises.lol/video-media/code_linux/redirection/redirection.thumb.jpg?v=1793262499Saving output to filesNormally a command's output appears on screen. Add an arrow and a filename and it does not — and the first time, that looks like nothing happened. It did: the…https://exercises.lol/video-media/code_linux/redirection/redirection.enzh.mp4?v=1793262499-21142026-08-23yes https://exercises.lol/videos/code_linux/pipes2026-10-30https://exercises.lol/video-media/code_linux/pipes/pipes.thumb.jpg?v=1793322495Pipes — joining commandsThis is the idea the command line is built on. A pipe sends one command's output straight into sort, as its input. Cat produces five lines; sort receives those…https://exercises.lol/video-media/code_linux/pipes/pipes.enzh.mp4?v=1793322495-21212026-08-23yes https://exercises.lol/videos/code_linux/grep2026-10-29https://exercises.lol/video-media/code_linux/grep/grep.thumb.jpg?v=1793304174Searching with grepA log file has forty thousand lines in it and you need the four that mention your program. Grep searches for a word and prints only the lines that contain it.…https://exercises.lol/video-media/code_linux/grep/grep.enzh.mp4?v=1793304174-21212026-08-23yes https://exercises.lol/videos/code_linux/find2026-10-28https://exercises.lol/video-media/code_linux/find/find.thumb.jpg?v=1793214635Finding files with findYou have known l s since lesson two, and it has one limit: it shows only what is right here, in this one folder. Find does not stop there. It walks every…https://exercises.lol/video-media/code_linux/find/find.enzh.mp4?v=1793214635-21192026-08-23yes https://exercises.lol/videos/code_linux/sorting2026-10-28https://exercises.lol/video-media/code_linux/sorting/sorting.thumb.jpg?v=1793227785Sorting and columnsA list in the order the machine happened to produce it is not a list anybody can use. Sort arranges lines in alphabetical order. Three fruits go in unordered…https://exercises.lol/video-media/code_linux/sorting/sorting.enzh.mp4?v=1793227785-21462026-08-23yes https://exercises.lol/videos/code_linux/permissions2026-10-30https://exercises.lol/video-media/code_linux/permissions/permissions.thumb.jpg?v=1793323032File permissionsRun l s dash l and every line starts with ten characters that look like line noise. They are not. They are four fields: one, then three threes. The first…https://exercises.lol/video-media/code_linux/permissions/permissions.enzh.mp4?v=1793323032-21402026-08-23yes https://exercises.lol/videos/code_linux/processes2026-10-28https://exercises.lol/video-media/code_linux/processes/processes.thumb.jpg?v=1793185551Programs and processesTwo words that sound the same and are not. A program is a file sitting on disk, doing nothing. A process is that file running — your browser, your editor, and…https://exercises.lol/video-media/code_linux/processes/processes.enzh.mp4?v=1793185551-21232026-08-23yes https://exercises.lol/videos/code_pseudocode/sequence-output2026-10-30https://exercises.lol/video-media/code_pseudocode/sequence-output/sequence-output.thumb.jpg?v=1793322713OUTPUT and sequenceCambridge exams write algorithms in pseudocode — not Python, not Java. It is a real notation with real keywords, and the paper expects those exact words. Here…https://exercises.lol/video-media/code_pseudocode/sequence-output/sequence-output.enzh.mp4?v=1793322713-21162026-08-23yes https://exercises.lol/videos/code_pseudocode/variables2026-10-28https://exercises.lol/video-media/code_pseudocode/variables/variables.thumb.jpg?v=1793178285Variables and DECLAREPseudocode has no computer to run it, so every rule about storing a value exists to be read by a person. A variable is a named store that holds one value. The…https://exercises.lol/video-media/code_pseudocode/variables/variables.enzh.mp4?v=1793178285-21152026-08-23yes https://exercises.lol/videos/code_pseudocode/input-types2026-10-29https://exercises.lol/video-media/code_pseudocode/input-types/input-types.thumb.jpg?v=1793311153INPUT and data typesEverything the user types arrives as text, including the numbers. That single fact is behind most lost marks here. INPUT reads one line that the user types and…https://exercises.lol/video-media/code_pseudocode/input-types/input-types.enzh.mp4?v=1793311153-21062026-08-23yes https://exercises.lol/videos/code_pseudocode/arithmetic2026-10-29https://exercises.lol/video-media/code_pseudocode/arithmetic/arithmetic.thumb.jpg?v=1793304548Arithmetic, DIV and MODPlus, minus, times and slash behave exactly as you would expect, and there is nothing to memorise about the first three. The fourth is worth a second look.…https://exercises.lol/video-media/code_pseudocode/arithmetic/arithmetic.enzh.mp4?v=1793304548-21152026-08-23yes https://exercises.lol/videos/code_pseudocode/selection-if2026-10-29https://exercises.lol/video-media/code_pseudocode/selection-if/selection-if.thumb.jpg?v=1793304874Selection: IFSelection is the second control structure, and it is one test with exactly two exits. If the test is true, the program takes the TRUE exit and runs the block…https://exercises.lol/video-media/code_pseudocode/selection-if/selection-if.enzh.mp4?v=1793304874-21162026-08-23yes https://exercises.lol/videos/code_pseudocode/selection-case2026-10-29https://exercises.lol/video-media/code_pseudocode/selection-case/selection-case.thumb.jpg?v=1793305040Selection: CASEWhen one variable is checked against several fixed values, a stack of IFs gets long. CASE says the same thing in one block. Grade holds two. CASE compares it…https://exercises.lol/video-media/code_pseudocode/selection-case/selection-case.enzh.mp4?v=1793305040-21132026-08-23yes https://exercises.lol/videos/code_pseudocode/iteration-for2026-10-29https://exercises.lol/video-media/code_pseudocode/iteration-for/iteration-for.thumb.jpg?v=1793304788Iteration: FORIteration is the third control structure, and a FOR loop is the version you use when you already know how many times. It has exactly one moving part: the…https://exercises.lol/video-media/code_pseudocode/iteration-for/iteration-for.enzh.mp4?v=1793304788-21192026-08-23yes https://exercises.lol/videos/code_pseudocode/iteration-while2026-10-30https://exercises.lol/video-media/code_pseudocode/iteration-while/iteration-while.thumb.jpg?v=1793322260Iteration: WHILE and REPEATWhen you do not know how many repeats you need, the test moves into the loop itself. In a WHILE loop the test is at the top: it is checked before you are let…https://exercises.lol/video-media/code_pseudocode/iteration-while/iteration-while.enzh.mp4?v=1793322260-21232026-08-23yes https://exercises.lol/videos/code_pseudocode/strings2026-10-30https://exercises.lol/video-media/code_pseudocode/strings/strings.thumb.jpg?v=1793322339String handlingThree of the string functions have nothing to trip on. LENGTH gives how many characters are in a string — hello is five. UCASE returns it in capitals, and…https://exercises.lol/video-media/code_pseudocode/strings/strings.enzh.mp4?v=1793322339-21262026-08-23yes https://exercises.lol/videos/code_pseudocode/arrays-1d2026-10-29https://exercises.lol/video-media/code_pseudocode/arrays-1d/arrays-1d.thumb.jpg?v=17933056241-D arraysCambridge writes a declaration in one line, and every part of that line is worth a mark. An array stores many values under one name, and the declaration says…https://exercises.lol/video-media/code_pseudocode/arrays-1d/arrays-1d.enzh.mp4?v=1793305624-21202026-08-23yes https://exercises.lol/videos/code_pseudocode/arrays-2d2026-10-29https://exercises.lol/video-media/code_pseudocode/arrays-2d/arrays-2d.thumb.jpg?v=17933058772-D arraysOne index finds a value in a row. A seating plan needs you to say which row first. A 2-D array is a grid — a table with rows and columns. The declaration has…https://exercises.lol/video-media/code_pseudocode/arrays-2d/arrays-2d.enzh.mp4?v=1793305877-21312026-08-23yes https://exercises.lol/videos/code_pseudocode/procedures2026-10-30https://exercises.lol/video-media/code_pseudocode/procedures/procedures.thumb.jpg?v=1793350487ProceduresA long algorithm written as one block is hard to mark and harder to read, and the exam rewards splitting it. A procedure is a named block of steps. You write…https://exercises.lol/video-media/code_pseudocode/procedures/procedures.enzh.mp4?v=1793350487-21252026-08-23yes https://exercises.lol/videos/code_pseudocode/functions2026-10-29https://exercises.lol/video-media/code_pseudocode/functions/functions.thumb.jpg?v=1793304676FunctionsA procedure does something. Sooner or later you need one that comes back with an answer. A function works something out and hands the answer back. Two words do…https://exercises.lol/video-media/code_pseudocode/functions/functions.enzh.mp4?v=1793304676-21242026-08-23yes https://exercises.lol/videos/code_pseudocode/standard-methods2026-10-29https://exercises.lol/video-media/code_pseudocode/standard-methods/standard-methods.thumb.jpg?v=1793304919Putting it togetherCambridge names four standard methods — totalling, counting, linear search, and finding the maximum or minimum — and it is tempting to learn them as four…https://exercises.lol/video-media/code_pseudocode/standard-methods/standard-methods.enzh.mp4?v=1793304919-21202026-08-23yes https://exercises.lol/videos/code_python_basics/first-program2026-10-28https://exercises.lol/video-media/code_python_basics/first-program/first-program.thumb.jpg?v=1793214025Your first programA computer is not clever. It cannot guess what you meant. It does exactly what you tell it, and nothing else. You write a line of instructions. Python reads…https://exercises.lol/video-media/code_python_basics/first-program/first-program.enzh.mp4?v=1793214025-22252026-08-22yes https://exercises.lol/videos/code_python_basics/variables2026-10-30https://exercises.lol/video-media/code_python_basics/variables/variables.thumb.jpg?v=1793319565VariablesSuppose your program mentions the same city three times. You could type it again, and again, and again — and then the day comes when the city changes, and you…https://exercises.lol/video-media/code_python_basics/variables/variables.enzh.mp4?v=1793319565-22172026-08-22yes https://exercises.lol/videos/code_python_basics/numbers-operators2026-10-28https://exercises.lol/video-media/code_python_basics/numbers-operators/numbers-operators.thumb.jpg?v=1793213828Numbers & operatorsYou do not have to teach Python arithmetic — it already knows. Write plus, minus, times, and it answers nine, five and fourteen without being told what those…https://exercises.lol/video-media/code_python_basics/numbers-operators/numbers-operators.enzh.mp4?v=1793213828-21872026-08-23yes https://exercises.lol/videos/code_python_basics/getting-input2026-10-30https://exercises.lol/video-media/code_python_basics/getting-input/getting-input.thumb.jpg?v=1793349665Getting inputEvery program so far has known everything in advance. Here the greeting works perfectly — for Sam. You wrote the name into the program, so Sam is the only…https://exercises.lol/video-media/code_python_basics/getting-input/getting-input.enzh.mp4?v=1793349665-21762026-08-22yes https://exercises.lol/videos/code_python_basics/strings2026-10-30https://exercises.lol/video-media/code_python_basics/strings/strings.thumb.jpg?v=1793350642Working with stringsYou have printed text and stored text. Getting one piece OUT of a piece of text is a different job, and it starts by counting from zero. A string is a row of…https://exercises.lol/video-media/code_python_basics/strings/strings.enzh.mp4?v=1793350642-21892026-08-22yes https://exercises.lol/videos/code_python_basics/making-decisions2026-10-30https://exercises.lol/video-media/code_python_basics/making-decisions/making-decisions.thumb.jpg?v=1793319410Making decisionsEverything you have written so far does the same thing every time it runs. Real programs need to choose. So you ask a question with a true-or-false answer — is…https://exercises.lol/video-media/code_python_basics/making-decisions/making-decisions.enzh.mp4?v=1793319410-22102026-08-23yes https://exercises.lol/videos/code_python_basics/counting-loops2026-10-27https://exercises.lol/video-media/code_python_basics/counting-loops/counting-loops.thumb.jpg?v=1793123205Counting loopsTo print the numbers one to five you could write it five times. It works. Now print one to five hundred, and the idea collapses — nobody types five hundred…https://exercises.lol/video-media/code_python_basics/counting-loops/counting-loops.enzh.mp4?v=1793123205-21822026-08-22yes https://exercises.lol/videos/code_python_basics/while-loops2026-10-27https://exercises.lol/video-media/code_python_basics/while-loops/while-loops.thumb.jpg?v=1793110820While loopsA for loop is perfect when you know the count in advance: print one to five, five passes, done. But now think about asking someone a question until they type…https://exercises.lol/video-media/code_python_basics/while-loops/while-loops.enzh.mp4?v=1793110820-21802026-08-23yes https://exercises.lol/videos/code_python_basics/lists2026-10-30https://exercises.lol/video-media/code_python_basics/lists/lists.thumb.jpg?v=1793318935ListsFive test scores, and so far you would give them a name each: score one, score two, and so on. It works until you need to add them up, and then you are writing…https://exercises.lol/video-media/code_python_basics/lists/lists.enzh.mp4?v=1793318935-21672026-08-22yes https://exercises.lol/videos/code_python_basics/functions2026-10-30https://exercises.lol/video-media/code_python_basics/functions/functions.thumb.jpg?v=1793319233FunctionsYou have written the same four lines twice: total starts at zero, loop, divide by the length. If a third list turns up you will copy it again — and the day you…https://exercises.lol/video-media/code_python_basics/functions/functions.enzh.mp4?v=1793319233-21722026-08-22yes https://exercises.lol/videos/code_python_basics/scope-arguments2026-10-29https://exercises.lol/video-media/code_python_basics/scope-arguments/scope-arguments.thumb.jpg?v=1793261204Scope & argumentsThink of your program as a room, and every function call as a smaller room inside it. A variable made inside the function belongs to that small room: it is…https://exercises.lol/video-media/code_python_basics/scope-arguments/scope-arguments.enzh.mp4?v=1793261204-21842026-08-23yes https://exercises.lol/videos/code_python_basics/dictionaries2026-10-28https://exercises.lol/video-media/code_python_basics/dictionaries/dictionaries.thumb.jpg?v=1793214246DictionariesStore a book in a list and you have to remember which position holds what. Was slot one the number of pages, or the year? Six months later you will guess…https://exercises.lol/video-media/code_python_basics/dictionaries/dictionaries.enzh.mp4?v=1793214246-21552026-08-22yes https://exercises.lol/videos/code_python_basics/planning2026-10-29https://exercises.lol/video-media/code_python_basics/planning/planning.thumb.jpg?v=1793311832Planning & pseudocodeWhen a task gets hard, the temptation is to start typing and hope. The faster way is to write the steps down in ordinary sentences first. Read the number.…https://exercises.lol/video-media/code_python_basics/planning/planning.enzh.mp4?v=1793311832-22012026-08-23yes https://exercises.lol/videos/code_python_basics/errors-testing2026-10-30https://exercises.lol/video-media/code_python_basics/errors-testing/errors-testing.thumb.jpg?v=1793318605Errors & testingErrors come in three kinds, and telling them apart tells you where to look. A syntax error breaks Python's own rules — a missing bracket, a missing colon — so…https://exercises.lol/video-media/code_python_basics/errors-testing/errors-testing.enzh.mp4?v=1793318605-21802026-08-22yes https://exercises.lol/videos/code_python_basics/putting-it-together2026-10-30https://exercises.lol/video-media/code_python_basics/putting-it-together/putting-it-together.thumb.jpg?v=1793330326Putting it all togetherThis is the last lesson, and it builds one small tool out of everything so far. You start with one list of scores. You want to know the average, how many…https://exercises.lol/video-media/code_python_basics/putting-it-together/putting-it-together.enzh.mp4?v=1793330326-21472026-08-22yes https://exercises.lol/videos/code_sql_databases/databases-select2026-10-29https://exercises.lol/video-media/code_sql_databases/databases-select/databases-select.thumb.jpg?v=1793235023Databases and SELECTA spreadsheet with fifty thousand rows is where a question goes to die. A database is the same grid, built to be asked. A database stores information in…https://exercises.lol/video-media/code_sql_databases/databases-select/databases-select.enzh.mp4?v=1793235023-21352026-08-23yes https://exercises.lol/videos/code_sql_databases/choosing-columns2026-10-30https://exercises.lol/video-media/code_sql_databases/choosing-columns/choosing-columns.thumb.jpg?v=1793322136Choosing columnsA star gives you every column, and usually you want only a few. So instead of the star, list the ones you want, separated by commas. The result keeps the two…https://exercises.lol/video-media/code_sql_databases/choosing-columns/choosing-columns.enzh.mp4?v=1793322136-2832026-08-23yes https://exercises.lol/videos/code_sql_databases/where2026-10-29https://exercises.lol/video-media/code_sql_databases/where/where.thumb.jpg?v=1793316432Filtering with WHEREEvery query so far returned all the rows. WHERE changes that: it keeps only the rows that match a condition. Scores of eighty or more, and the other two…https://exercises.lol/video-media/code_sql_databases/where/where.enzh.mp4?v=1793316432-21162026-08-23yes https://exercises.lol/videos/code_sql_databases/and-or-not2026-10-30https://exercises.lol/video-media/code_sql_databases/and-or-not/and-or-not.thumb.jpg?v=1793322495AND, OR and NOTA WHERE can test more than one thing. AND requires both to be true. Take form equals eleven A on its own and three survive: Mei, Sara and Lin. Now add AND…https://exercises.lol/video-media/code_sql_databases/and-or-not/and-or-not.enzh.mp4?v=1793322495-21142026-08-23yes https://exercises.lol/videos/code_sql_databases/order-by2026-10-30https://exercises.lol/video-media/code_sql_databases/order-by/order-by.thumb.jpg?v=1793323184Sorting with ORDER BYRows come back in no particular order. It usually LOOKS like insertion order, but nothing promises that, and a database is free to change it. ORDER BY is how…https://exercises.lol/video-media/code_sql_databases/order-by/order-by.enzh.mp4?v=1793323184-21192026-08-23yes https://exercises.lol/videos/code_sql_databases/aggregates2026-10-30https://exercises.lol/video-media/code_sql_databases/aggregates/aggregates.thumb.jpg?v=1793322633Counting and averagingSometimes you do not want the rows, you want a summary of them. An aggregate function does that, and it changes the shape of the answer: five rows go in and…https://exercises.lol/video-media/code_sql_databases/aggregates/aggregates.enzh.mp4?v=1793322633-21212026-08-23yes https://exercises.lol/videos/code_sql_databases/like-in-between2026-10-29https://exercises.lol/video-media/code_sql_databases/like-in-between/like-in-between.thumb.jpg?v=1793263161LIKE, IN and BETWEENSometimes you do not know the exact value — you know the shape of it. LIKE compares against a pattern. Here are our five students, three times over. Anything…https://exercises.lol/video-media/code_sql_databases/like-in-between/like-in-between.enzh.mp4?v=1793263161-21232026-08-23yes https://exercises.lol/videos/code_sql_databases/group-by2026-10-28https://exercises.lol/video-media/code_sql_databases/group-by/group-by.thumb.jpg?v=1793186141Grouping with GROUP BYLast lesson an aggregate folded the whole table into one number. Usually you want one number per something — per form, per customer, per month. GROUP BY does…https://exercises.lol/video-media/code_sql_databases/group-by/group-by.enzh.mp4?v=1793186141-21242026-08-23yes https://exercises.lol/videos/code_sql_databases/keys2026-10-28https://exercises.lol/video-media/code_sql_databases/keys/keys.thumb.jpg?v=1793216595Tables, keys and relationshipsReal databases hold several tables, and the reason is easiest to see by doing it wrong first. Put everything in one table and Ada's name and city are written…https://exercises.lol/video-media/code_sql_databases/keys/keys.enzh.mp4?v=1793216595-21272026-08-23yes https://exercises.lol/videos/code_sql_databases/inner-join2026-10-30https://exercises.lol/video-media/code_sql_databases/inner-join/inner-join.thumb.jpg?v=1793321461INNER JOINSplitting the data was the right thing to do, but now a question about customers and their orders touches both tables. A join puts them back together, and ON…https://exercises.lol/video-media/code_sql_databases/inner-join/inner-join.enzh.mp4?v=1793321461-21222026-08-23yes https://exercises.lol/videos/code_sql_databases/join-group2026-10-30https://exercises.lol/video-media/code_sql_databases/join-group/join-group.thumb.jpg?v=1793322789Joins with groupingEverything in this lesson you have already met. A join makes one wide table. GROUP BY sorts that into piles. An aggregate turns each pile into one row each.…https://exercises.lol/video-media/code_sql_databases/join-group/join-group.enzh.mp4?v=1793322789-21182026-08-23yes https://exercises.lol/videos/code_sql_databases/create-table2026-10-28https://exercises.lol/video-media/code_sql_databases/create-table/create-table.thumb.jpg?v=1793217082Creating tablesSQL splits into two halves, and it is worth being able to name them. DDL, the data definition language, changes the structure — the tables themselves. DML, the…https://exercises.lol/video-media/code_sql_databases/create-table/create-table.enzh.mp4?v=1793217082-21282026-08-23yes https://exercises.lol/videos/code_sql_databases/alter-drop2026-10-30https://exercises.lol/video-media/code_sql_databases/alter-drop/alter-drop.thumb.jpg?v=1793322563Changing the schemaA table's design is not fixed once it is made. ALTER TABLE ADD gives an existing table a new column, named and typed just as it would have been in the CREATE.…https://exercises.lol/video-media/code_sql_databases/alter-drop/alter-drop.enzh.mp4?v=1793322563-21132026-08-23yes https://exercises.lol/videos/code_sql_databases/insert2026-10-28https://exercises.lol/video-media/code_sql_databases/insert/insert.thumb.jpg?v=1793229722Inserting rowsA table with no rows in it is a shape, not data. This is the statement that puts something inside it. INSERT adds a row. Name the table, list the columns you…https://exercises.lol/video-media/code_sql_databases/insert/insert.enzh.mp4?v=1793229722-21172026-08-23yes https://exercises.lol/videos/code_sql_databases/update2026-10-29https://exercises.lol/video-media/code_sql_databases/update/update.thumb.jpg?v=1793234579Updating rowsSomebody changes their phone number. You do not want a new row - you want the one that is already there to be right. UPDATE changes values in rows that already…https://exercises.lol/video-media/code_sql_databases/update/update.enzh.mp4?v=1793234579-21212026-08-23yes https://exercises.lol/videos/code_sql_databases/delete2026-10-27https://exercises.lol/video-media/code_sql_databases/delete/delete.thumb.jpg?v=1793142188Deleting rowsThere is no undo. Every DELETE you will ever write should be a SELECT first. DELETE removes rows. Name the table and give a WHERE, and that one row goes — the…https://exercises.lol/video-media/code_sql_databases/delete/delete.enzh.mp4?v=1793142188-21142026-08-23yes https://exercises.lol/videos/code_sql_databases/normalisation2026-10-30https://exercises.lol/video-media/code_sql_databases/normalisation/normalisation.thumb.jpg?v=1793322203NormalisationPut every club booking in one table and something goes wrong quietly. Look at the coach column: Mr Ng is written twice over, once for each Chess booking. If he…https://exercises.lol/video-media/code_sql_databases/normalisation/normalisation.enzh.mp4?v=1793322203-21502026-08-23yes https://exercises.lol/videos/code_web_basics/first-page2026-10-29https://exercises.lol/video-media/code_web_basics/first-page/first-page.thumb.jpg?v=1793236648Your first web pageEvery page you have ever opened is a file somebody typed. Not drawn, not designed in an app - typed, and you can type one in the next five minutes. A web page…https://exercises.lol/video-media/code_web_basics/first-page/first-page.enzh.mp4?v=1793236648-21402026-08-23yes https://exercises.lol/videos/code_web_basics/headings2026-10-30https://exercises.lol/video-media/code_web_basics/headings/headings.thumb.jpg?v=1793338566HeadingsA page of paragraphs all the same size is a wall of text, and a reader bounces off it. Headings are how a reader finds the part they came for. A heading is a…https://exercises.lol/video-media/code_web_basics/headings/headings.enzh.mp4?v=1793338566-21482026-08-23yes https://exercises.lol/videos/code_web_basics/emphasis2026-10-30https://exercises.lol/video-media/code_web_basics/emphasis/emphasis.thumb.jpg?v=1793322702Bold, italic, breakUntil now a tag has wrapped a whole block: this line is a paragraph, this line is a heading. Here is something new — a tag that wraps just one word in the…https://exercises.lol/video-media/code_web_basics/emphasis/emphasis.enzh.mp4?v=1793322702-21252026-08-23yes https://exercises.lol/videos/code_web_basics/lists2026-10-30https://exercises.lol/video-media/code_web_basics/lists/lists.thumb.jpg?v=1793348480ListsWrite three items as three paragraphs and the browser has no idea they belong together. Say list, and it does. A list takes two different tags, and that is the…https://exercises.lol/video-media/code_web_basics/lists/lists.enzh.mp4?v=1793348480-21372026-08-23yes https://exercises.lol/videos/code_web_basics/links2026-10-30https://exercises.lol/video-media/code_web_basics/links/links.thumb.jpg?v=1793323062LinksEverything you have written so far sits on one page and stays there. One tag turns it into part of the web. The link tag is a, short for anchor, and it brings…https://exercises.lol/video-media/code_web_basics/links/links.enzh.mp4?v=1793323062-21502026-08-23yes https://exercises.lol/videos/code_web_basics/real-page2026-10-30https://exercises.lol/video-media/code_web_basics/real-page/real-page.thumb.jpg?v=1793324842A real web pageSo far you have written pieces of a page. A real page puts them in a frame, and it is the same frame on essentially every website in the world, so it is worth…https://exercises.lol/video-media/code_web_basics/real-page/real-page.enzh.mp4?v=1793324842-21382026-08-23yes https://exercises.lol/videos/code_web_basics/nesting2026-10-29https://exercises.lol/video-media/code_web_basics/nesting/nesting.thumb.jpg?v=1793266541Comments and nestingSo far every tag has been a neighbour of the last one. Real pages put tags INSIDE tags, and the moment they do, order starts to matter. A comment is a note you…https://exercises.lol/video-media/code_web_basics/nesting/nesting.enzh.mp4?v=1793266541-21482026-08-23yes https://exercises.lol/videos/code_web_basics/tables2026-10-30https://exercises.lol/video-media/code_web_basics/tables/tables.thumb.jpg?v=1793343531TablesThis is the tag students most often get wrong, and always for the same reason: they guess the order instead of reading it. A table needs three tags nested…https://exercises.lol/video-media/code_web_basics/tables/tables.enzh.mp4?v=1793343531-21372026-08-23yes https://exercises.lol/videos/code_web_basics/forms2026-10-30https://exercises.lol/video-media/code_web_basics/forms/forms.thumb.jpg?v=1793322919FormsEverything you have made so far is something to read. A form is different: it is something a visitor uses. Write an input with type text and you get a real box…https://exercises.lol/video-media/code_web_basics/forms/forms.enzh.mp4?v=1793322919-21272026-08-23yes https://exercises.lol/videos/code_web_basics/sections2026-10-30https://exercises.lol/video-media/code_web_basics/sections/sections.thumb.jpg?v=1793322124Sections and classesSmall pages are fine as one stack of tags. Bigger ones are not — a visitor sees a title, then the content, then a note at the bottom, and if your HTML is just…https://exercises.lol/video-media/code_web_basics/sections/sections.enzh.mp4?v=1793322124-21382026-08-23yes https://exercises.lol/videos/code_web_basics/selectors2026-10-28https://exercises.lol/video-media/code_web_basics/selectors/selectors.thumb.jpg?v=1793216289SelectorsLast lesson your selector was a tag name, which changes every paragraph on the page. That is often too many. So there are two more. Write a name with a dot in…https://exercises.lol/video-media/code_web_basics/selectors/selectors.enzh.mp4?v=1793216289-21372026-08-23yes https://exercises.lol/videos/code_web_basics/colours2026-10-29https://exercises.lol/video-media/code_web_basics/colours/colours.thumb.jpg?v=1793233030ColoursColour is where a page stops looking like homework. It is also where a beginner picks twelve of them and the page falls apart. The simplest way to write a…https://exercises.lol/video-media/code_web_basics/colours/colours.enzh.mp4?v=1793233030-21382026-08-23yes https://exercises.lol/videos/code_web_basics/text-style2026-10-30https://exercises.lol/video-media/code_web_basics/text-style/text-style.thumb.jpg?v=1793323305Styling textBack in lesson two the browser chose your heading sizes for you. Now you can choose them yourself, with font-size, measured in pixels. Forty pixels for a…https://exercises.lol/video-media/code_web_basics/text-style/text-style.enzh.mp4?v=1793323305-21352026-08-23yes https://exercises.lol/videos/code_web_basics/box-model2026-10-30https://exercises.lol/video-media/code_web_basics/box-model/box-model.thumb.jpg?v=1793339165The box modelTwo elements refuse to sit where you want them, and nothing you type fixes it. Almost every time, this is why. CSS treats every single element as a box, and…https://exercises.lol/video-media/code_web_basics/box-model/box-model.enzh.mp4?v=1793339165-21462026-08-23yes https://exercises.lol/videos/code_web_basics/spacing2026-10-30https://exercises.lol/video-media/code_web_basics/spacing/spacing.thumb.jpg?v=1793323152MarginMargin is the space outside a box, and here is the thing about it: on a box with nothing around it, a margin changes nothing you can see. Put two boxes…https://exercises.lol/video-media/code_web_basics/spacing/spacing.enzh.mp4?v=1793323152-21362026-08-23yes https://exercises.lol/videos/code_web_basics/display2026-10-28https://exercises.lol/video-media/code_web_basics/display/display.thumb.jpg?v=1793212447displayYou have been watching this since lesson three without a name for it. Some elements take a whole line to themselves and stretch across the page: a div, a…https://exercises.lol/video-media/code_web_basics/display/display.enzh.mp4?v=1793212447-21362026-08-23yes https://exercises.lol/videos/code_web_basics/width2026-10-28https://exercises.lol/video-media/code_web_basics/width/width.thumb.jpg?v=1793216337Width and centeringHere is something you may not have noticed: a block box is already as wide as the page. It has been all along — you just could not see the edges without a…https://exercises.lol/video-media/code_web_basics/width/width.enzh.mp4?v=1793216337-21282026-08-23yes https://exercises.lol/videos/code_web_basics/flexbox2026-10-30https://exercises.lol/video-media/code_web_basics/flexbox/flexbox.thumb.jpg?v=1793323411FlexboxEverything you have built so far stacks downward, because that is what block boxes do. But a navigation bar, a row of cards, a toolbar — those need to sit…https://exercises.lol/video-media/code_web_basics/flexbox/flexbox.enzh.mp4?v=1793323411-21172026-08-23yes https://exercises.lol/videos/code_web_basics/profile-card2026-10-30https://exercises.lol/video-media/code_web_basics/profile-card/profile-card.thumb.jpg?v=1793326449Your profile cardLast lesson, and it is a project rather than a new idea. You are building a profile card: a picture at the top, a name in a colour you choose, and one line…https://exercises.lol/video-media/code_web_basics/profile-card/profile-card.enzh.mp4?v=1793326449-21392026-08-23yes https://exercises.lol/videos/edexcel_ial_biology/molecules-diet-transport-and-health2026-10-29https://exercises.lol/video-media/edexcel_ial_biology/molecules-diet-transport-and-health/molecules-diet-transport-and-health.thumb.jpg?v=1793310990Unit 1: Molecules, Diet, Transport and HealthA red blood cell leaving your lung carries oxygen on haemoglobin, rides an artery, squeezes through a capillary narrower than itself, gives up the oxygen to a…https://exercises.lol/video-media/edexcel_ial_biology/molecules-diet-transport-and-health/molecules-diet-transport-and-health.enzh.mp4?v=1793310990-26382026-10-10yes https://exercises.lol/videos/edexcel_ial_biology/cells-development-biodiversity-and-conservation2026-11-04https://exercises.lol/video-media/edexcel_ial_biology/cells-development-biodiversity-and-conservation/cells-development-biodiversity-and-conservation.thumb.jpg?v=1793790918Unit 2: Cells, Development, Biodiversity and ConservationYou began as one fertilised egg cell. This unit explains how that cell divided, how the copies were shuffled and halved into gametes, how identical genes…https://exercises.lol/video-media/edexcel_ial_biology/cells-development-biodiversity-and-conservation/cells-development-biodiversity-and-conservation.enzh.mp4?v=1793790918-25142026-10-10yes https://exercises.lol/videos/edexcel_ial_biology/energy-environment-microbiology-and-immunity2026-10-29https://exercises.lol/video-media/edexcel_ial_biology/energy-environment-microbiology-and-immunity/energy-environment-microbiology-and-immunity.thumb.jpg?v=1793307878Unit 4: Energy, Environment, Microbiology and ImmunityA wheat field intercepts sunlight, fixes carbon, feeds a food chain - and loses energy at every step. This unit follows the energy from photon to ecosystem…https://exercises.lol/video-media/edexcel_ial_biology/energy-environment-microbiology-and-immunity/energy-environment-microbiology-and-immunity.enzh.mp4?v=1793307878-25342026-10-10yes https://exercises.lol/videos/edexcel_ial_biology/respiration-internal-environment-coordination-and-gene-technology2026-10-30https://exercises.lol/video-media/edexcel_ial_biology/respiration-internal-environment-coordination-and-gene-technology/respiration-internal-environment-coordination-and-gene-technology.thumb.jpg?v=1793319276Unit 5: Respiration, Internal Environment, Coordination and Gene TechnologySprint for a bus and your body performs a symphony: muscles burn glucose faster, the heart doubles its output, ventilation deepens, sweat starts, the kidney…https://exercises.lol/video-media/edexcel_ial_biology/respiration-internal-environment-coordination-and-gene-technology/respiration-internal-environment-coordination-and-gene-technology.enzh.mp4?v=1793319276-25392026-10-10yes https://exercises.lol/videos/edexcel_ial_chemistry/structure-bonding-and-organic-introduction2026-10-31https://exercises.lol/video-media/edexcel_ial_chemistry/structure-bonding-and-organic-introduction/structure-bonding-and-organic-introduction.thumb.jpg?v=1793405373Unit 1: Structure, bonding and organic introductionUse particle models to explain properties, then balanced equations to calculate amounts. Prerequisites: algebra, powers of ten and conservation of atoms and…https://exercises.lol/video-media/edexcel_ial_chemistry/structure-bonding-and-organic-introduction/structure-bonding-and-organic-introduction.enzh.mp4?v=1793405373-210642026-10-28yes https://exercises.lol/videos/edexcel_ial_chemistry/energetics-groups-and-organic-reactions2026-10-31https://exercises.lol/video-media/edexcel_ial_chemistry/energetics-groups-and-organic-reactions/energetics-groups-and-organic-reactions.thumb.jpg?v=1793411865Unit 2: Energetics, groups and organic reactionsEnergy, attractions, electron transfer and collision models explain different observations. Use Unit 1 mole ratios, polarity and structural formulae; state…https://exercises.lol/video-media/edexcel_ial_chemistry/energetics-groups-and-organic-reactions/energetics-groups-and-organic-reactions.enzh.mp4?v=1793411865-219812026-10-28yes https://exercises.lol/videos/edexcel_ial_chemistry/rates-equilibria-and-further-organic-chemistry2026-11-08https://exercises.lol/video-media/edexcel_ial_chemistry/rates-equilibria-and-further-organic-chemistry/rates-equilibria-and-further-organic-chemistry.thumb.jpg?v=1794117174Unit 4: Rates, equilibria and further organic chemistryRate concerns speed; total entropy concerns feasibility; K concerns equilibrium composition. Use Unit 1 mole ratios and Unit 2 energy, collision and…https://exercises.lol/video-media/edexcel_ial_chemistry/rates-equilibria-and-further-organic-chemistry/rates-equilibria-and-further-organic-chemistry.enzh.mp4?v=1794117174-218502026-10-28yes https://exercises.lol/videos/edexcel_ial_chemistry/transition-metals-and-organic-nitrogen-chemistry2026-10-28https://exercises.lol/video-media/edexcel_ial_chemistry/transition-metals-and-organic-nitrogen-chemistry/transition-metals-and-organic-nitrogen-chemistry.thumb.jpg?v=1793225352Unit 5: Transition metals and organic nitrogen chemistryTrack electrons in cells and metal redox cycles. Track lone pairs in complexes and organic reactions. Use Units 1, 2 and 4 as prerequisites.https://exercises.lol/video-media/edexcel_ial_chemistry/transition-metals-and-organic-nitrogen-chemistry/transition-metals-and-organic-nitrogen-chemistry.enzh.mp4?v=1793225352-26982026-10-28yes https://exercises.lol/videos/edexcel_ial_economics/topic-012026-10-30https://exercises.lol/video-media/edexcel_ial_economics/topic-01/topic-01.thumb.jpg?v=1793395491Choice, models and market adjustmentOne model runs through this topic. Demand is quantity equals 140 minus 2 P; supply is quantity equals 20 plus 4 P. They meet at a price of 20 and a quantity of…https://exercises.lol/video-media/edexcel_ial_economics/topic-01/topic-01.enzh.mp4?v=1793395491-24072026-10-28yes https://exercises.lol/videos/edexcel_ial_economics/topic-022026-10-30https://exercises.lol/video-media/edexcel_ial_economics/topic-02/topic-02.thumb.jpg?v=1793395364Market failure and government interventionMarkets sometimes fail, producing too much or too little. Government intervenes to correct them. But intervention can fail too, leaving a net welfare loss.https://exercises.lol/video-media/edexcel_ial_economics/topic-02/topic-02.enzh.mp4?v=1793395364-23432026-10-28yes https://exercises.lol/videos/edexcel_ial_economics/topic-032026-10-30https://exercises.lol/video-media/edexcel_ial_economics/topic-03/topic-03.thumb.jpg?v=1793395515Output measures, spending and the multiplierThis topic measures economic performance, then explains it. Aggregate demand and aggregate supply set output and the price level. The multiplier enlarges every…https://exercises.lol/video-media/edexcel_ial_economics/topic-03/topic-03.enzh.mp4?v=1793395515-24612026-10-28yes https://exercises.lol/videos/edexcel_ial_economics/topic-042026-11-08https://exercises.lol/video-media/edexcel_ial_economics/topic-04/topic-04.thumb.jpg?v=1794116584Inflation, unemployment and policy judgementWhy it matters. In 1979 prices in the USA were rising by more than 13% a year. Paul Volcker, the new chair of the Federal Reserve, decided to stop inflation…https://exercises.lol/video-media/edexcel_ial_economics/topic-04/topic-04.enzh.mp4?v=1794116584-210552026-10-28yes https://exercises.lol/videos/edexcel_ial_economics/topic-052026-11-08https://exercises.lol/video-media/edexcel_ial_economics/topic-05/topic-05.thumb.jpg?v=1794117695Firms, costs, growth and competitionWhy it matters. From 2014 to 2016 two ride-hailing firms fought for China's cities. Didi Chuxing and Uber China both paid drivers bonuses and gave passengers…https://exercises.lol/video-media/edexcel_ial_economics/topic-05/topic-05.enzh.mp4?v=1794117695-215802026-10-28yes https://exercises.lol/videos/edexcel_ial_economics/topic-062026-11-08https://exercises.lol/video-media/edexcel_ial_economics/topic-06/topic-06.thumb.jpg?v=1794116744Labour markets and government interventionWhy it matters. On 1 April 1992 the US state of New Jersey raised its minimum wage from 4.25 to 5.05 an hour, while neighbouring Pennsylvania kept $4.25.…https://exercises.lol/video-media/edexcel_ial_economics/topic-06/topic-06.enzh.mp4?v=1794116744-211132026-10-28yes https://exercises.lol/videos/edexcel_ial_economics/topic-072026-10-30https://exercises.lol/video-media/edexcel_ial_economics/topic-07/topic-07.thumb.jpg?v=1793395322Globalisation, trade and international financeGlobalisation links economies. Comparative advantage explains why countries specialise and trade. Blocs and tariffs shape that trade. And the balance of…https://exercises.lol/video-media/edexcel_ial_economics/topic-07/topic-07.enzh.mp4?v=1793395322-22552026-10-28yes https://exercises.lol/videos/edexcel_ial_economics/topic-082026-11-08https://exercises.lol/video-media/edexcel_ial_economics/topic-08/topic-08.thumb.jpg?v=1794117977Poverty, the state and developmentWhy it matters. In 1981 about 88% of China's people lived below the World Bank's extreme-poverty line of the time. On 25 February 2021 China's government…https://exercises.lol/video-media/edexcel_ial_economics/topic-08/topic-08.enzh.mp4?v=1794117977-218202026-10-28yes https://exercises.lol/videos/edexcel_ial_further_mathematics/topic-012026-10-28https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-01/topic-01.thumb.jpg?v=1793226117Further Pure Mathematics 1Paper WFM01: 1 hour 30 minutes, 75 marks, with P1 and P2 assumed. Five families of formulae are not in the booklet: the root sum and product, the sum of r, the…https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-01/topic-01.enzh.mp4?v=1793226117-25052026-10-28yes https://exercises.lol/videos/edexcel_ial_further_mathematics/topic-022026-11-08https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-02/topic-02.thumb.jpg?v=1794120349Further Pure Mathematics 2Why it matters. In 1748 the Swiss mathematician Leonhard Euler, then working at the Berlin Academy, published Introductio in analysin infinitorum, a textbook…https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-02/topic-02.enzh.mp4?v=1794120349-215262026-10-28yes https://exercises.lol/videos/edexcel_ial_further_mathematics/topic-032026-11-08https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-03/topic-03.thumb.jpg?v=1794127157Further Pure Mathematics 3Why it matters. What shape does a chain make when it hangs between two posts? Galileo thought it was a parabola, and for decades nobody could prove otherwise.…https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-03/topic-03.enzh.mp4?v=1794127157-214222026-10-28yes https://exercises.lol/videos/edexcel_ial_further_mathematics/topic-042026-11-08https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-04/topic-04.thumb.jpg?v=1794118843Mechanics 1Why it matters. In 1638 Galileo Galilei, old, nearly blind and under house arrest near Florence, published Two New Sciences in Leiden in the Netherlands, out…https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-04/topic-04.enzh.mp4?v=1794118843-210302026-10-28yes https://exercises.lol/videos/edexcel_ial_further_mathematics/topic-052026-11-08https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-05/topic-05.thumb.jpg?v=1794119252Mechanics 2Why it matters. In the Principia (London, 1687), Isaac Newton described an experiment to test his laws of motion. He hung two balls as pendulums, pulled them…https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-05/topic-05.enzh.mp4?v=1794119252-213192026-10-28yes https://exercises.lol/videos/edexcel_ial_further_mathematics/topic-062026-11-08https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-06/topic-06.thumb.jpg?v=1794119724Mechanics 3Why it matters. In 1676 Robert Hooke printed a puzzle at the end of a book about helioscopes: the letters "ceiiinosssttuv". He had found a law of nature but…https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-06/topic-06.enzh.mp4?v=1794119724-211362026-10-28yes https://exercises.lol/videos/edexcel_ial_further_mathematics/topic-072026-11-08https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-07/topic-07.thumb.jpg?v=1794120302Statistics 1Why it matters. In 1886 Francis Galton published a study of the heights of 928 adult children and their 205 pairs of parents. Tall parents usually had tall…https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-07/topic-07.enzh.mp4?v=1794120302-211452026-10-28yes https://exercises.lol/videos/edexcel_ial_further_mathematics/topic-082026-11-08https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-08/topic-08.thumb.jpg?v=1794127282Statistics 2Why it matters. In 1898 the Russian-born statistician Ladislaus von Bortkiewicz published Das Gesetz der kleinen Zahlen (The Law of Small Numbers) in Leipzig.…https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-08/topic-08.enzh.mp4?v=1794127282-211162026-10-28yes https://exercises.lol/videos/edexcel_ial_further_mathematics/topic-092026-11-08https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-09/topic-09.thumb.jpg?v=1794125900Statistics 3Why it matters. The biologist Raphael Weldon threw twelve dice 26,306 times and counted how many showed a 5 or a 6 each time. If the dice were fair, the counts…https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-09/topic-09.enzh.mp4?v=1794125900-211202026-10-28yes https://exercises.lol/videos/edexcel_ial_further_mathematics/topic-102026-11-08https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-10/topic-10.thumb.jpg?v=1794119357Decision Mathematics 1Why it matters. One morning in 1956, Edsger Dijkstra, a 26-year-old programmer at the Mathematical Centre in Amsterdam, was shopping with his fiancée. Tired…https://exercises.lol/video-media/edexcel_ial_further_mathematics/topic-10/topic-10.enzh.mp4?v=1794119357-29592026-10-28yes https://exercises.lol/videos/edexcel_ial_mathematics/topic-012026-11-08https://exercises.lol/video-media/edexcel_ial_mathematics/topic-01/topic-01.thumb.jpg?v=1794126043Pure Mathematics 1Why it matters. In October 1684 Gottfried Wilhelm Leibniz published a six-page paper in the Leipzig journal Acta Eruditorum. Its Latin title began Nova…https://exercises.lol/video-media/edexcel_ial_mathematics/topic-01/topic-01.enzh.mp4?v=1794126043-217102026-10-28yes https://exercises.lol/videos/edexcel_ial_mathematics/topic-022026-11-08https://exercises.lol/video-media/edexcel_ial_mathematics/topic-02/topic-02.thumb.jpg?v=1794122615Pure Mathematics 2Why it matters. In 1614 the Scottish landowner John Napier published Mirifici Logarithmorum Canonis Descriptio (A Description of the Wonderful Table of…https://exercises.lol/video-media/edexcel_ial_mathematics/topic-02/topic-02.enzh.mp4?v=1794122615-215032026-10-28yes https://exercises.lol/videos/edexcel_ial_mathematics/topic-032026-11-08https://exercises.lol/video-media/edexcel_ial_mathematics/topic-03/topic-03.thumb.jpg?v=1794124537Pure Mathematics 3Why it matters. In 1683 the Swiss mathematician Jacob Bernoulli asked a question about money. If a bank pays 100% interest a year, £1 becomes £2. If it pays…https://exercises.lol/video-media/edexcel_ial_mathematics/topic-03/topic-03.enzh.mp4?v=1794124537-211952026-10-28yes https://exercises.lol/videos/edexcel_ial_mathematics/topic-042026-11-08https://exercises.lol/video-media/edexcel_ial_mathematics/topic-04/topic-04.thumb.jpg?v=1794125734Pure Mathematics 4Why it matters. About 300 BC, in Alexandria, Euclid collected the mathematics of his time into the thirteen books of the Elements. Book IX, Proposition 20…https://exercises.lol/video-media/edexcel_ial_mathematics/topic-04/topic-04.enzh.mp4?v=1794125734-212682026-10-28yes https://exercises.lol/videos/edexcel_ial_mathematics/topic-052026-10-28https://exercises.lol/video-media/edexcel_ial_mathematics/topic-05/topic-05.thumb.jpg?v=1793227486Mechanics 1Paper WME01: 1 hour 30 minutes, 75 marks, with P1 and P2 assumed. Take g as 9.8, give inexact answers to 2 or 3 significant figures, and memorise these…https://exercises.lol/video-media/edexcel_ial_mathematics/topic-05/topic-05.enzh.mp4?v=1793227486-23082026-10-28yes https://exercises.lol/videos/edexcel_ial_mathematics/topic-062026-11-08https://exercises.lol/video-media/edexcel_ial_mathematics/topic-06/topic-06.thumb.jpg?v=1794125530Statistics 1Why it matters. In 1886 Francis Galton published a study of the heights of 928 adult children and their 205 pairs of parents. Tall parents usually had tall…https://exercises.lol/video-media/edexcel_ial_mathematics/topic-06/topic-06.enzh.mp4?v=1794125530-211452026-10-28yes https://exercises.lol/videos/edexcel_ial_mathematics/topic-072026-10-28https://exercises.lol/video-media/edexcel_ial_mathematics/topic-07/topic-07.thumb.jpg?v=1793227734Mechanics 2Paper WME02: 1 hour 30 minutes, 75 marks, with P1 to P4 and M1 assumed. Memorise kinetic and potential energy, work and power; v and s as integrals; and…https://exercises.lol/video-media/edexcel_ial_mathematics/topic-07/topic-07.enzh.mp4?v=1793227734-23452026-10-28yes https://exercises.lol/videos/edexcel_ial_mathematics/topic-082026-11-08https://exercises.lol/video-media/edexcel_ial_mathematics/topic-08/topic-08.thumb.jpg?v=1794126527Statistics 2Why it matters. In 1898 the Russian-born statistician Ladislaus von Bortkiewicz published Das Gesetz der kleinen Zahlen (The Law of Small Numbers) in Leipzig.…https://exercises.lol/video-media/edexcel_ial_mathematics/topic-08/topic-08.enzh.mp4?v=1794126527-211162026-10-28yes https://exercises.lol/videos/edexcel_ial_mathematics/topic-092026-11-08https://exercises.lol/video-media/edexcel_ial_mathematics/topic-09/topic-09.thumb.jpg?v=1794120355Decision Mathematics 1Why it matters. One morning in 1956, Edsger Dijkstra, a 26-year-old programmer at the Mathematical Centre in Amsterdam, was shopping with his fiancée. Tired…https://exercises.lol/video-media/edexcel_ial_mathematics/topic-09/topic-09.enzh.mp4?v=1794120355-29592026-10-28yes https://exercises.lol/videos/edexcel_ial_physics/mechanics-and-materials2026-10-29https://exercises.lol/video-media/edexcel_ial_physics/mechanics-and-materials/mechanics-and-materials.thumb.jpg?v=1793316372Unit 1: Mechanics and MaterialsStart with the physical situation, not a formula search. Unit one connects descriptions of motion with causes, then uses momentum and energy to explain…https://exercises.lol/video-media/edexcel_ial_physics/mechanics-and-materials/mechanics-and-materials.enzh.mp4?v=1793316372-211022026-10-09yes https://exercises.lol/videos/edexcel_ial_physics/waves-and-electricity2026-10-29https://exercises.lol/video-media/edexcel_ial_physics/waves-and-electricity/waves-and-electricity.thumb.jpg?v=1793309291Unit 2: Waves and ElectricityA phone connects the two halves of this unit. Waves bring information, and a battery supplies electrical energy. Start each problem with the physical model.…https://exercises.lol/video-media/edexcel_ial_physics/waves-and-electricity/waves-and-electricity.enzh.mp4?v=1793309291-28892026-10-09yes https://exercises.lol/videos/edexcel_ial_physics/practical-skills-in-physics-i2026-10-30https://exercises.lol/video-media/edexcel_ial_physics/practical-skills-in-physics-i/practical-skills-in-physics-i.thumb.jpg?v=1793319881Unit 3: Practical Skills in Physics ITwo groups report different wire diameters. The extra decimal places do not tell us which result is better. We need the instrument, its zero check, the contact…https://exercises.lol/video-media/edexcel_ial_physics/practical-skills-in-physics-i/practical-skills-in-physics-i.enzh.mp4?v=1793319881-26192026-10-09yes https://exercises.lol/videos/edexcel_ial_physics/further-mechanics-fields-and-particles2026-10-28https://exercises.lol/video-media/edexcel_ial_physics/further-mechanics-fields-and-particles/further-mechanics-fields-and-particles.thumb.jpg?v=1793191099Unit 4: Further Mechanics, Fields and ParticlesA car bumper changes a momentum transfer by changing the stopping time. A detector uses curved tracks to infer momentum. We will connect those ideas through…https://exercises.lol/video-media/edexcel_ial_physics/further-mechanics-fields-and-particles/further-mechanics-fields-and-particles.enzh.mp4?v=1793191099-215032026-10-09yes https://exercises.lol/videos/edexcel_ial_physics/thermodynamics-radiation-oscillations-and-cosmology2026-10-29https://exercises.lol/video-media/edexcel_ial_physics/thermodynamics-radiation-oscillations-and-cosmology/thermodynamics-radiation-oscillations-and-cosmology.thumb.jpg?v=1793310756Unit 5: Thermodynamics, Radiation, Oscillations and CosmologyAn ice pack absorbs energy without necessarily warming. A star emits energy while its nuclear fuel changes. This lesson connects those ideas through nine skill…https://exercises.lol/video-media/edexcel_ial_physics/thermodynamics-radiation-oscillations-and-cosmology/thermodynamics-radiation-oscillations-and-cosmology.enzh.mp4?v=1793310756-215802026-10-09yes https://exercises.lol/videos/edexcel_ial_physics/practical-skills-in-physics-ii2026-11-08https://exercises.lol/video-media/edexcel_ial_physics/practical-skills-in-physics-ii/practical-skills-in-physics-ii.thumb.jpg?v=1794106842Unit 6: Practical Skills in Physics IITwo students measure the same damped pendulum. One writes down amplitudes. The other processes them with logarithms, draws one straight line, and reads a decay…https://exercises.lol/video-media/edexcel_ial_physics/practical-skills-in-physics-ii/practical-skills-in-physics-ii.enzh.mp4?v=1794106842-28662026-10-09yes https://exercises.lol/videos/edexcel_ial_pure_mathematics/topic-012026-10-28https://exercises.lol/video-media/edexcel_ial_pure_mathematics/topic-01/topic-01.thumb.jpg?v=1793227958Pure Mathematics 1Paper WMA11: 1 hour 30 minutes, 75 marks. These formulae are not in the booklet, so memorise them: the quadratic formula, the sine and cosine rules, the…https://exercises.lol/video-media/edexcel_ial_pure_mathematics/topic-01/topic-01.enzh.mp4?v=1793227958-23482026-10-28yes https://exercises.lol/videos/edexcel_ial_pure_mathematics/topic-022026-11-08https://exercises.lol/video-media/edexcel_ial_pure_mathematics/topic-02/topic-02.thumb.jpg?v=1794124963Pure Mathematics 2Why it matters. In 1614 the Scottish landowner John Napier published Mirifici Logarithmorum Canonis Descriptio (A Description of the Wonderful Table of…https://exercises.lol/video-media/edexcel_ial_pure_mathematics/topic-02/topic-02.enzh.mp4?v=1794124963-215032026-10-28yes https://exercises.lol/videos/edexcel_ial_pure_mathematics/topic-032026-10-31https://exercises.lol/video-media/edexcel_ial_pure_mathematics/topic-03/topic-03.thumb.jpg?v=1793405486Pure Mathematics 3Paper WMA13: 1 hour 30 minutes, 75 marks, with P1 and P2 assumed. None of these are in the booklet: the compound and double angle formulae, the reciprocal…https://exercises.lol/video-media/edexcel_ial_pure_mathematics/topic-03/topic-03.enzh.mp4?v=1793405486-22572026-10-28yes https://exercises.lol/videos/edexcel_ial_pure_mathematics/topic-042026-11-08https://exercises.lol/video-media/edexcel_ial_pure_mathematics/topic-04/topic-04.thumb.jpg?v=1794120913Pure Mathematics 4Why it matters. About 300 BC, in Alexandria, Euclid collected the mathematics of his time into the thirteen books of the Elements. Book IX, Proposition 20…https://exercises.lol/video-media/edexcel_ial_pure_mathematics/topic-04/topic-04.enzh.mp4?v=1794120913-212682026-10-28yes https://exercises.lol/videos/edexcel_ial_pure_mathematics/topic-052026-11-08https://exercises.lol/video-media/edexcel_ial_pure_mathematics/topic-05/topic-05.thumb.jpg?v=1794122004Further Pure Mathematics 1Why it matters. In 1545 the Italian doctor and mathematician Gerolamo Cardano published Ars Magna (The Great Art), with the first printed method for solving…https://exercises.lol/video-media/edexcel_ial_pure_mathematics/topic-05/topic-05.enzh.mp4?v=1794122004-214302026-10-28yes https://exercises.lol/videos/edexcel_ial_pure_mathematics/topic-062026-11-08https://exercises.lol/video-media/edexcel_ial_pure_mathematics/topic-06/topic-06.thumb.jpg?v=1794121931Further Pure Mathematics 2Why it matters. In 1748 the Swiss mathematician Leonhard Euler, then working at the Berlin Academy, published Introductio in analysin infinitorum, a textbook…https://exercises.lol/video-media/edexcel_ial_pure_mathematics/topic-06/topic-06.enzh.mp4?v=1794121931-215262026-10-28yes https://exercises.lol/videos/edexcel_ial_pure_mathematics/topic-072026-10-28https://exercises.lol/video-media/edexcel_ial_pure_mathematics/topic-07/topic-07.thumb.jpg?v=1793228525Further Pure Mathematics 3Paper WFM03: 1 hour 30 minutes, 75 marks, the last pure unit, with P1 to P4 and FP1 assumed. It adds hyperbolic functions and their inverses, the ellipse and…https://exercises.lol/video-media/edexcel_ial_pure_mathematics/topic-07/topic-07.enzh.mp4?v=1793228525-24872026-10-28yes https://exercises.lol/videos/edexcel_igcse_economics/topic-012026-10-30https://exercises.lol/video-media/edexcel_igcse_economics/topic-01/topic-01.thumb.jpg?v=1793395303The economic problem and economic assumptionsThis topic has three strands. Scarcity forces every economy to choose. The production possibility frontier draws those choices. And economists assume consumers…https://exercises.lol/video-media/edexcel_igcse_economics/topic-01/topic-01.enzh.mp4?v=1793395303-21852026-10-28yes https://exercises.lol/videos/edexcel_igcse_economics/topic-022026-10-30https://exercises.lol/video-media/edexcel_igcse_economics/topic-02/topic-02.thumb.jpg?v=1793393626Demand, supply, equilibrium and elasticityThis topic builds one market model. Demand and supply meet at the equilibrium price. Elasticity then measures how strongly quantity responds to price and to…https://exercises.lol/video-media/edexcel_igcse_economics/topic-02/topic-02.enzh.mp4?v=1793393626-23392026-10-28yes https://exercises.lol/videos/edexcel_igcse_economics/topic-032026-11-08https://exercises.lol/video-media/edexcel_igcse_economics/topic-03/topic-03.thumb.jpg?v=1794117451The mixed economy and externalitiesWhy it matters. Every phone with satellite navigation can pick up free signals from China's BeiDou system, completed in 2020 with 30 satellites in its final…https://exercises.lol/video-media/edexcel_igcse_economics/topic-03/topic-03.enzh.mp4?v=1794117451-27592026-10-28yes https://exercises.lol/videos/edexcel_igcse_economics/topic-042026-11-08https://exercises.lol/video-media/edexcel_igcse_economics/topic-04/topic-04.thumb.jpg?v=1794115834Production, productivity and business costsWhy it matters. In 1913 Henry Ford's factory in Detroit tried something new: instead of a team of workers building each car in one place, the car moved past…https://exercises.lol/video-media/edexcel_igcse_economics/topic-04/topic-04.enzh.mp4?v=1794115834-28632026-10-28yes https://exercises.lol/videos/edexcel_igcse_economics/topic-052026-10-30https://exercises.lol/video-media/edexcel_igcse_economics/topic-05/topic-05.thumb.jpg?v=1793393296Business competition, the labour market and government interventionThis topic has three parts. How firms compete, from many small firms to a single monopoly. How the labour market sets wages and employment. And how government…https://exercises.lol/video-media/edexcel_igcse_economics/topic-05/topic-05.enzh.mp4?v=1793393296-23262026-10-27yes https://exercises.lol/videos/edexcel_igcse_economics/topic-062026-10-30https://exercises.lol/video-media/edexcel_igcse_economics/topic-06/topic-06.thumb.jpg?v=1793393447Government and the economyGovernments chase six macroeconomic objectives. They pull three main policy levers: fiscal, monetary and supply-side. And because the objectives clash, every…https://exercises.lol/video-media/edexcel_igcse_economics/topic-06/topic-06.enzh.mp4?v=1793393447-23082026-10-27yes https://exercises.lol/videos/edexcel_igcse_economics/topic-072026-10-30https://exercises.lol/video-media/edexcel_igcse_economics/topic-07/topic-07.thumb.jpg?v=1793395633The global economyThis topic follows economies as they integrate. Globalisation ties them together. International trade brings gains, and governments sometimes protect against…https://exercises.lol/video-media/edexcel_igcse_economics/topic-07/topic-07.enzh.mp4?v=1793395633-23032026-10-28yes https://exercises.lol/videos/edexcel_igcse_mathematics/topic-012026-11-08https://exercises.lol/video-media/edexcel_igcse_mathematics/topic-01/topic-01.thumb.jpg?v=1794120653Numbers and the number systemWhy it matters. In the year 628, the Indian mathematician Brahmagupta wrote the Brāhmasphuṭasiddhānta, the first book to treat zero as a number in its own…https://exercises.lol/video-media/edexcel_igcse_mathematics/topic-01/topic-01.enzh.mp4?v=1794120653-210332026-10-28yes https://exercises.lol/videos/edexcel_igcse_mathematics/topic-022026-11-08https://exercises.lol/video-media/edexcel_igcse_mathematics/topic-02/topic-02.thumb.jpg?v=1794122507Equations, formulae and identitiesWhy it matters. Around the year 820, Muhammad ibn Musa al-Khwarizmi, a scholar at the House of Wisdom in Baghdad, wrote a book on solving equations called…https://exercises.lol/video-media/edexcel_igcse_mathematics/topic-02/topic-02.enzh.mp4?v=1794122507-213402026-10-28yes https://exercises.lol/videos/edexcel_igcse_mathematics/topic-032026-10-31https://exercises.lol/video-media/edexcel_igcse_mathematics/topic-03/topic-03.thumb.jpg?v=1793406006Sequences, functions and graphsTopic 3 is the heaviest strand on the Higher papers. The nth term of an arithmetic sequence is a plus n minus 1 times d, and the sum pairs the first with the…https://exercises.lol/video-media/edexcel_igcse_mathematics/topic-03/topic-03.enzh.mp4?v=1793406006-23162026-10-28yes https://exercises.lol/videos/edexcel_igcse_mathematics/topic-042026-10-29https://exercises.lol/video-media/edexcel_igcse_mathematics/topic-04/topic-04.thumb.jpg?v=1793238071Geometry and trigonometryTopic 4 is the largest topic. The Higher formulae sheet gives the sine and cosine rules, the area half a b sine C, and the cone and sphere formulae. Arcs…https://exercises.lol/video-media/edexcel_igcse_mathematics/topic-04/topic-04.enzh.mp4?v=1793238071-23432026-10-28yes https://exercises.lol/videos/edexcel_igcse_mathematics/topic-052026-11-08https://exercises.lol/video-media/edexcel_igcse_mathematics/topic-05/topic-05.thumb.jpg?v=1794123135Vectors and transformation geometryWhy it matters. In 1586 the Flemish engineer Simon Stevin published De Beghinselen der Weeghconst (The Elements of the Art of Weighing). On its title page is a…https://exercises.lol/video-media/edexcel_igcse_mathematics/topic-05/topic-05.enzh.mp4?v=1794123135-27302026-10-28yes https://exercises.lol/videos/edexcel_igcse_mathematics/topic-062026-10-29https://exercises.lol/video-media/edexcel_igcse_mathematics/topic-06/topic-06.thumb.jpg?v=1793239226Statistics and probabilityFour families carry topic 6. A grouped mean uses midpoints. A histogram bar's area is its frequency, so its height is frequency density. Cumulative frequency…https://exercises.lol/video-media/edexcel_igcse_mathematics/topic-06/topic-06.enzh.mp4?v=1793239226-22272026-10-28yes https://exercises.lol/videos/en_a1/the-verb-to-be2026-10-31https://exercises.lol/video-media/en_a1/the-verb-to-be/the-verb-to-be.thumb.jpg?v=1793409530English A1 · The verb to beGood news: you already know this grammar. In Chinese you say wo shi xuesheng, and English has the same idea: I am a student. There is only one difference, and…https://exercises.lol/video-media/en_a1/the-verb-to-be/the-verb-to-be.enzh.mp4?v=1793409530-25472026-10-08yes https://exercises.lol/videos/en_a1/pronouns-and-possessives2026-11-08https://exercises.lol/video-media/en_a1/pronouns-and-possessives/pronouns-and-possessives.thumb.jpg?v=1794121335English A1 · Pronouns and possessivesA pronoun is a small word that stands in for a name: I, you, he, she, it, we, they. Chinese has them too, so the idea is old news. The new part is that English…https://exercises.lol/video-media/en_a1/pronouns-and-possessives/pronouns-and-possessives.enzh.mp4?v=1794121335-24172026-10-08yes https://exercises.lol/videos/en_a1/this-that-these-those2026-10-30https://exercises.lol/video-media/en_a1/this-that-these-those/this-that-these-those.thumb.jpg?v=1793392247English A1 · this, that, these, thoseChinese has zhe and na, and English has the same pair: this and that. You are halfway done before you begin. The only new machinery is the plural pair, these…https://exercises.lol/video-media/en_a1/this-that-these-those/this-that-these-those.enzh.mp4?v=1793392247-23012026-10-08yes https://exercises.lol/videos/en_a1/a-an-and-plurals2026-10-30https://exercises.lol/video-media/en_a1/a-an-and-plurals/a-an-and-plurals.thumb.jpg?v=1793398314English A1 · a, an and pluralsChinese gets through life without articles; wo you yi ben shu needs no little word before the noun. English cannot manage that. A singular countable noun…https://exercises.lol/video-media/en_a1/a-an-and-plurals/a-an-and-plurals.enzh.mp4?v=1793398314-23142026-10-08yes https://exercises.lol/videos/en_a1/there-is-and-there-are2026-10-30https://exercises.lol/video-media/en_a1/there-is-and-there-are/there-is-and-there-are.thumb.jpg?v=1793399213English A1 · there is and there areHow do you say that something exists? Chinese uses you: zhuo shang you yi ben shu. English does not let the table have the book. Instead it sends a little word…https://exercises.lol/video-media/en_a1/there-is-and-there-are/there-is-and-there-are.enzh.mp4?v=1793399213-22802026-10-08yes https://exercises.lol/videos/en_a1/have-got2026-10-30https://exercises.lol/video-media/en_a1/have-got/have-got.thumb.jpg?v=1793399469English A1 · have gotChinese uses one word, you, for two jobs: existence, as in zhuo shang you yi ben shu, and possession, as in wo you yi zhi mao. Topic five covered existence…https://exercises.lol/video-media/en_a1/have-got/have-got.enzh.mp4?v=1793399469-22642026-10-08yes https://exercises.lol/videos/en_a1/present-simple2026-10-30https://exercises.lol/video-media/en_a1/present-simple/present-simple.thumb.jpg?v=1793398438English A1 · Present simpleThe present simple is the tense of things that are always true: habits, routines and facts. I walk to school. The sun rises in the east. My cat sleeps twenty…https://exercises.lol/video-media/en_a1/present-simple/present-simple.enzh.mp4?v=1793398438-23252026-10-08yes https://exercises.lol/videos/en_a1/can2026-10-30https://exercises.lol/video-media/en_a1/can/can.thumb.jpg?v=1793399260English A1 · canCan is the little verb of ability, permission and requests. Chinese spreads these jobs across hui, keyi and neng; English packs them into one word. I can swim.…https://exercises.lol/video-media/en_a1/can/can.enzh.mp4?v=1793399260-22612026-10-08yes https://exercises.lol/videos/en_a1/imperatives-and-question-words2026-10-30https://exercises.lol/video-media/en_a1/imperatives-and-question-words/imperatives-and-question-words.thumb.jpg?v=1793392233English A1 · Imperatives and question wordsTwo survival tools in one topic. The imperative tells people what to do: sit down, listen, don't run. The question words ask for information: what, where…https://exercises.lol/video-media/en_a1/imperatives-and-question-words/imperatives-and-question-words.enzh.mp4?v=1793392233-23042026-10-08yes https://exercises.lol/videos/en_a1/prepositions-of-place2026-10-30https://exercises.lol/video-media/en_a1/prepositions-of-place/prepositions-of-place.thumb.jpg?v=1793399102English A1 · Prepositions of placeWhere is your phone? In your bag? On your desk? Under a pile of homework? The little words that answer are the prepositions of place. Chinese has the same map…https://exercises.lol/video-media/en_a1/prepositions-of-place/prepositions-of-place.enzh.mp4?v=1793399102-22862026-10-08yes https://exercises.lol/videos/en_a1/listening-names-numbers2026-11-08https://exercises.lol/video-media/en_a1/listening-names-numbers/listening-names-numbers.thumb.jpg?v=1794107570English A1 · Listening: names, numbers and introductionsListening at A1 is not about speed. It is about catching the parts that matter. In a first meeting you only need three things: the name, the number, and who is…https://exercises.lol/video-media/en_a1/listening-names-numbers/listening-names-numbers.enzh.mp4?v=1794107570-21692026-10-28yes https://exercises.lol/videos/en_a1/saying-the-ends-of-words2026-11-08https://exercises.lol/video-media/en_a1/saying-the-ends-of-words/saying-the-ends-of-words.thumb.jpg?v=1794116999English A1 · Saying the ends of wordsChinese words end softly, with a vowel or an n. English words end with consonants, and often with a chain of them. The ending is the door of the word: close…https://exercises.lol/video-media/en_a1/saying-the-ends-of-words/saying-the-ends-of-words.enzh.mp4?v=1794116999-21872026-10-28yes https://exercises.lol/videos/en_a1/word-stress-and-rhythm2026-11-08https://exercises.lol/video-media/en_a1/word-stress-and-rhythm/word-stress-and-rhythm.thumb.jpg?v=1794117011English A1 · Word stress and sentence rhythmChinese gives every syllable almost the same time. English does not: it squeezes the small words and makes the important ones loud and long. English is a drum…https://exercises.lol/video-media/en_a1/word-stress-and-rhythm/word-stress-and-rhythm.enzh.mp4?v=1794117011-21712026-10-28yes https://exercises.lol/videos/en_a1/reading-notes-signs-messages2026-11-08https://exercises.lol/video-media/en_a1/reading-notes-signs-messages/reading-notes-signs-messages.thumb.jpg?v=1794116967English A1 · Reading: notes, signs and messagesA1 reading is not reading everything; it is reading for the purpose. A note on a door, a sign on a wall and a text on a phone each want something from you.…https://exercises.lol/video-media/en_a1/reading-notes-signs-messages/reading-notes-signs-messages.enzh.mp4?v=1794116967-21992026-10-28yes https://exercises.lol/videos/en_a1/speaking-introductions2026-11-08https://exercises.lol/video-media/en_a1/speaking-introductions/speaking-introductions.thumb.jpg?v=1794117019English A1 · Speaking: introductions and meeting peopleMeeting people is a dance with fixed steps: greeting, names, a moment of small talk, and a clean goodbye. You already know this dance in Chinese. This topic…https://exercises.lol/video-media/en_a1/speaking-introductions/speaking-introductions.enzh.mp4?v=1794117019-21922026-10-28yes https://exercises.lol/videos/en_a1/writing-short-message2026-11-08https://exercises.lol/video-media/en_a1/writing-short-message/writing-short-message.thumb.jpg?v=1794117018English A1 · Writing: a useful short messageA useful short message does one job: it makes the reader do something. A note on a table, a text to a parent, a message to a teacher: same skeleton, five…https://exercises.lol/video-media/en_a1/writing-short-message/writing-short-message.enzh.mp4?v=1794117018-21772026-10-28yes https://exercises.lol/videos/en_a2/present-simple-revisited2026-10-30https://exercises.lol/video-media/en_a2/present-simple-revisited/present-simple-revisited.thumb.jpg?v=1793399724English A2 · Present simpleYou met the present simple in A1: I walk, she walks, does he like cats. This topic is the same tense with the lights turned up, three new rooms in a house you…https://exercises.lol/video-media/en_a2/present-simple-revisited/present-simple-revisited.enzh.mp4?v=1793399724-22842026-10-08yes https://exercises.lol/videos/en_a2/present-continuous2026-10-30https://exercises.lol/video-media/en_a2/present-continuous/present-continuous.thumb.jpg?v=1793398378English A2 · Present continuousThe present continuous is the tense of right now, and it is built from two parts: be plus verb-ing. Be is the engine, ing is the wheels, and the sentence needs…https://exercises.lol/video-media/en_a2/present-continuous/present-continuous.enzh.mp4?v=1793398378-22832026-10-08yes https://exercises.lol/videos/en_a2/past-simple2026-10-30https://exercises.lol/video-media/en_a2/past-simple/past-simple.thumb.jpg?v=1793397673English A2 · Past simpleThe past simple talks about finished past events, things that started and ended with a door closed behind them. Wo zuotian kanle yi bu dianying: I watched a…https://exercises.lol/video-media/en_a2/past-simple/past-simple.enzh.mp4?v=1793397673-22702026-10-08yes https://exercises.lol/videos/en_a2/present-perfect2026-10-30https://exercises.lol/video-media/en_a2/present-perfect/present-perfect.thumb.jpg?v=1793392220English A2 · Present perfectThe present perfect is the tense of the open door: a past event with a connection to now. The form is have or has plus the past participle: I have eaten; she…https://exercises.lol/video-media/en_a2/present-perfect/present-perfect.enzh.mp4?v=1793392220-22782026-10-08yes https://exercises.lol/videos/en_a2/talking-about-the-future2026-10-30https://exercises.lol/video-media/en_a2/talking-about-the-future/talking-about-the-future.thumb.jpg?v=1793398604English A2 · Talking about the futureChinese talks about the future with hui or yao plus a time word, and the verb never changes. English has three doors into the future: will, going to, and the…https://exercises.lol/video-media/en_a2/talking-about-the-future/talking-about-the-future.enzh.mp4?v=1793398604-22782026-10-08yes https://exercises.lol/videos/en_a2/comparatives-and-superlatives2026-10-30https://exercises.lol/video-media/en_a2/comparatives-and-superlatives/comparatives-and-superlatives.thumb.jpg?v=1793398311English A2 · Comparatives and superlativesChinese compares with bi: wo bi wo gege gao. English changes the adjective itself: taller than. And for the winner of the whole group, the superlative: the…https://exercises.lol/video-media/en_a2/comparatives-and-superlatives/comparatives-and-superlatives.enzh.mp4?v=1793398311-22652026-10-08yes https://exercises.lol/videos/en_a2/articles2026-10-29https://exercises.lol/video-media/en_a2/articles/articles.thumb.jpg?v=1793311880English A2 · ArticlesA1 gave you the ticket: a or an for one unknown thing. A2 adds the spotlight: the, for the exact one you and your listener both know. And the third article is…https://exercises.lol/video-media/en_a2/articles/articles.enzh.mp4?v=1793311880-22772026-10-08yes https://exercises.lol/videos/en_a2/countable-and-uncountable-nouns2026-10-30https://exercises.lol/video-media/en_a2/countable-and-uncountable-nouns/countable-and-uncountable-nouns.thumb.jpg?v=1793399723English A2 · Countable and uncountable nounsEnglish divides nouns into two families. Countable nouns can be counted on your fingers: a book, two books, many books. Uncountable nouns are soup: you cannot…https://exercises.lol/video-media/en_a2/countable-and-uncountable-nouns/countable-and-uncountable-nouns.enzh.mp4?v=1793399723-22692026-10-08yes https://exercises.lol/videos/en_a2/modal-verbs2026-10-30https://exercises.lol/video-media/en_a2/modal-verbs/modal-verbs.thumb.jpg?v=1793399782English A2 · Modal verbsCan was one verb; now meet the whole family. The modal verbs: can, could, may, might, must, should, will, would. Family rules: one shape for all persons, and…https://exercises.lol/video-media/en_a2/modal-verbs/modal-verbs.enzh.mp4?v=1793399782-22582026-10-08yes https://exercises.lol/videos/en_a2/prepositions-and-connectors2026-10-30https://exercises.lol/video-media/en_a2/prepositions-and-connectors/prepositions-and-connectors.thumb.jpg?v=1793398593English A2 · Prepositions and connectorsYou know the prepositions of place from A1. Now meet the time versions, plus the connectors, the glue that joins two ideas into one sentence. The memory hook…https://exercises.lol/video-media/en_a2/prepositions-and-connectors/prepositions-and-connectors.enzh.mp4?v=1793398593-22722026-10-08yes https://exercises.lol/videos/en_a2/listening-routines-times2026-11-08https://exercises.lol/video-media/en_a2/listening-routines-times/listening-routines-times.thumb.jpg?v=1794117126English A2 · Listening: routines, times and arrangementsA2 listening catches three kinds of time. The routine, heard in the present simple with frequency words: I usually get up at seven. The clock, in two…https://exercises.lol/video-media/en_a2/listening-routines-times/listening-routines-times.enzh.mp4?v=1794117126-21832026-10-28yes https://exercises.lol/videos/en_a2/word-order2026-11-08https://exercises.lol/video-media/en_a2/word-order/word-order.thumb.jpg?v=1794117225English A2 · Word order for Chinese speakersChinese lets its sentences flow around the known and the new, like a river. English is a train. The engine is the subject, the first car is the verb, the…https://exercises.lol/video-media/en_a2/word-order/word-order.enzh.mp4?v=1794117225-21942026-10-28yes https://exercises.lol/videos/en_a2/reading-emails-notices-stories2026-11-08https://exercises.lol/video-media/en_a2/reading-emails-notices-stories/reading-emails-notices-stories.thumb.jpg?v=1794106913English A2 · Reading: emails, notices and short storiesA2 reading meets you with three shapes: the email, the notice and the short story. Each has a skeleton, and the skeleton tells you where to look first. Read…https://exercises.lol/video-media/en_a2/reading-emails-notices-stories/reading-emails-notices-stories.enzh.mp4?v=1794106913-21752026-10-28yes https://exercises.lol/videos/en_a2/speaking-routines-plans-requests2026-11-08https://exercises.lol/video-media/en_a2/speaking-routines-plans-requests/speaking-routines-plans-requests.thumb.jpg?v=1794117186English A2 · Speaking: routines, plans and asking for thingsA2 speaking runs on three engines. The routine engine, the present simple with frequency words: I usually play basketball on Saturdays. The plan engine, with…https://exercises.lol/video-media/en_a2/speaking-routines-plans-requests/speaking-routines-plans-requests.enzh.mp4?v=1794117186-21862026-10-28yes https://exercises.lol/videos/en_a2/writing-change-a-plan2026-11-08https://exercises.lol/video-media/en_a2/writing-change-a-plan/writing-change-a-plan.thumb.jpg?v=1794107769English A2 · Writing: change a plan politelyPlans break; politeness does not. Changing a plan in writing is a four-step dance: apologise, reason, proposal, confirm. Steps one and two take the wall down…https://exercises.lol/video-media/en_a2/writing-change-a-plan/writing-change-a-plan.enzh.mp4?v=1794107769-21582026-10-28yes https://exercises.lol/videos/en_b1/present-perfect-vs-past-simple2026-10-30https://exercises.lol/video-media/en_b1/present-perfect-vs-past-simple/present-perfect-vs-past-simple.thumb.jpg?v=1793393354English B1 · Present perfect vs past simpleYou know both doors from A2. B1 is where you stop knowing the rules and start choosing correctly under pressure. The memory hook: the past simple is a…https://exercises.lol/video-media/en_b1/present-perfect-vs-past-simple/present-perfect-vs-past-simple.enzh.mp4?v=1793393354-22682026-10-08yes https://exercises.lol/videos/en_b1/present-perfect-continuous2026-10-30https://exercises.lol/video-media/en_b1/present-perfect-continuous/present-perfect-continuous.thumb.jpg?v=1793395855English B1 · Present perfect continuousThe present perfect continuous is have been plus verb-ing, for an action that started in the past and is still in progress, or just stopped with the evidence…https://exercises.lol/video-media/en_b1/present-perfect-continuous/present-perfect-continuous.enzh.mp4?v=1793395855-22842026-10-08yes https://exercises.lol/videos/en_b1/past-perfect2026-10-31https://exercises.lol/video-media/en_b1/past-perfect/past-perfect.thumb.jpg?v=1793406545English B1 · Past perfectThe past perfect is had plus the past participle, the tense for the earlier of two past events. When I arrived, the train had left: first the train left, then…https://exercises.lol/video-media/en_b1/past-perfect/past-perfect.enzh.mp4?v=1793406545-22742026-10-08yes https://exercises.lol/videos/en_b1/used-to2026-10-30https://exercises.lol/video-media/en_b1/used-to/used-to.thumb.jpg?v=1793399499English B1 · used toSome past habits are gone forever, and English has a form for exactly that: used to plus the base verb, for past habits and states that are no longer true. I…https://exercises.lol/video-media/en_b1/used-to/used-to.enzh.mp4?v=1793399499-22582026-10-08yes https://exercises.lol/videos/en_b1/future-forms-review2026-10-30https://exercises.lol/video-media/en_b1/future-forms-review/future-forms-review.thumb.jpg?v=1793392454English B1 · Future forms reviewYou know the four doors from A2. B1 adds the rule that separates good English from translated Chinese: in a time clause, use the present simple, never will.…https://exercises.lol/video-media/en_b1/future-forms-review/future-forms-review.enzh.mp4?v=1793392454-22522026-10-08yes https://exercises.lol/videos/en_b1/conditionals2026-10-30https://exercises.lol/video-media/en_b1/conditionals/conditionals.thumb.jpg?v=1793392241English B1 · ConditionalsIf-sentences imagine worlds, and English has three. The verbs step backwards to show how real the world is: present for facts, will for a real future, and the…https://exercises.lol/video-media/en_b1/conditionals/conditionals.enzh.mp4?v=1793392241-22762026-10-08yes https://exercises.lol/videos/en_b1/the-passive2026-10-30https://exercises.lol/video-media/en_b1/the-passive/the-passive.thumb.jpg?v=1793393135English B1 · The passiveSometimes the thing that receives the action is the star. The active says the cat ate the homework; the passive swaps the spotlight: the homework was eaten, by…https://exercises.lol/video-media/en_b1/the-passive/the-passive.enzh.mp4?v=1793393135-22422026-10-08yes https://exercises.lol/videos/en_b1/reported-speech2026-10-30https://exercises.lol/video-media/en_b1/reported-speech/reported-speech.thumb.jpg?v=1793399215English B1 · Reported speechDirect speech quotes the exact words: she said, I am tired. Reported speech rebuilds the sentence: she said she was tired. The memory hook: a retelling, not a…https://exercises.lol/video-media/en_b1/reported-speech/reported-speech.enzh.mp4?v=1793399215-22752026-10-08yes https://exercises.lol/videos/en_b1/relative-clauses2026-10-30https://exercises.lol/video-media/en_b1/relative-clauses/relative-clauses.thumb.jpg?v=1793398831English B1 · Relative clausesA relative clause is a small sentence inside a big one, glued on with who, which, that, where or whose. The girl who lives next door is my friend. And here is…https://exercises.lol/video-media/en_b1/relative-clauses/relative-clauses.enzh.mp4?v=1793398831-22352026-10-08yes https://exercises.lol/videos/en_b1/gerunds-and-infinitives2026-10-30https://exercises.lol/video-media/en_b1/gerunds-and-infinitives/gerunds-and-infinitives.thumb.jpg?v=1793393302English B1 · Gerunds and infinitivesWhen a verb acts like a thing, English gives it one of two costumes: the gerund, swimming, or the infinitive, to swim. I enjoy swimming; I want to swim.…https://exercises.lol/video-media/en_b1/gerunds-and-infinitives/gerunds-and-infinitives.enzh.mp4?v=1793393302-22832026-10-08yes https://exercises.lol/videos/en_b1/listening-stories-directions-opinions2026-11-08https://exercises.lol/video-media/en_b1/listening-stories-directions-opinions/listening-stories-directions-opinions.thumb.jpg?v=1794118744English B1 · Listening: stories, directions and opinionsB1 listening follows three currents: the story, the directions, and the opinion. A story is a chain with named links: first, then, suddenly, in the end.…https://exercises.lol/video-media/en_b1/listening-stories-directions-opinions/listening-stories-directions-opinions.enzh.mp4?v=1794118744-21902026-10-28yes https://exercises.lol/videos/en_b1/reading-blogs-reviews-articles2026-10-30https://exercises.lol/video-media/en_b1/reading-blogs-reviews-articles/reading-blogs-reviews-articles.thumb.jpg?v=1793404082English B1 · Reading: blogs, reviews and articlesB1 reading meets three grown-up shapes. The blog: one voice, one experience, feelings allowed. The review: a verdict with reasons, and the reviewer needs on…https://exercises.lol/video-media/en_b1/reading-blogs-reviews-articles/reading-blogs-reviews-articles.enzh.mp4?v=1793404082-21742026-10-28yes https://exercises.lol/videos/en_b1/speaking-stories-opinions-discussions2026-10-29https://exercises.lol/video-media/en_b1/speaking-stories-opinions-discussions/speaking-stories-opinions-discussions.thumb.jpg?v=1793265323English B1 · Speaking: stories, opinions and discussionsB1 speaking holds the floor. You tell a story to the end, with signposts for the ear. You state an opinion with a frame, a reason and an edge soft enough to…https://exercises.lol/video-media/en_b1/speaking-stories-opinions-discussions/speaking-stories-opinions-discussions.enzh.mp4?v=1793265323-21682026-10-28yes https://exercises.lol/videos/en_b1/writing-problem-solution2026-11-08https://exercises.lol/video-media/en_b1/writing-problem-solution/writing-problem-solution.thumb.jpg?v=1794117243English B1 · Writing: explain a problem and request a solutionA B1 problem message is a small machine with four gears. The situation orients: one sentence of who, where, what. The problem is factual: dates, numbers, what…https://exercises.lol/video-media/en_b1/writing-problem-solution/writing-problem-solution.enzh.mp4?v=1794117243-21852026-10-28yes https://exercises.lol/videos/en_b2/narrative-tenses2026-10-30https://exercises.lol/video-media/en_b2/narrative-tenses/narrative-tenses.thumb.jpg?v=1793399496English B2 · Narrative tensesA good story needs three tenses working together, and the memory hook is a film. The past continuous is the weather, the background in progress. The past…https://exercises.lol/video-media/en_b2/narrative-tenses/narrative-tenses.enzh.mp4?v=1793399496-22402026-10-08yes https://exercises.lol/videos/en_b2/future-continuous-and-perfect2026-10-30https://exercises.lol/video-media/en_b2/future-continuous-and-perfect/future-continuous-and-perfect.thumb.jpg?v=1793393094English B2 · Future continuous and perfectTwo tenses that look into the future with a camera. The future continuous, will be plus verb-ing, shows an action in progress at a future moment: this time…https://exercises.lol/video-media/en_b2/future-continuous-and-perfect/future-continuous-and-perfect.enzh.mp4?v=1793393094-22622026-10-08yes https://exercises.lol/videos/en_b2/third-and-mixed-conditionals2026-10-30https://exercises.lol/video-media/en_b2/third-and-mixed-conditionals/third-and-mixed-conditionals.thumb.jpg?v=1793399711English B2 · Third and mixed conditionalsB1's second conditional imagines a different present. B2 adds the imagined past: the third conditional, and the mixed conditional, where an imagined past…https://exercises.lol/video-media/en_b2/third-and-mixed-conditionals/third-and-mixed-conditionals.enzh.mp4?v=1793399711-22242026-10-08yes https://exercises.lol/videos/en_b2/wish-and-if-only2026-10-30https://exercises.lol/video-media/en_b2/wish-and-if-only/wish-and-if-only.thumb.jpg?v=1793398746English B2 · wish and if onlyWish and if only are the polite cousins of the conditionals. The verb inside the wish wears the costume of the unreal: the past form for the present you want…https://exercises.lol/video-media/en_b2/wish-and-if-only/wish-and-if-only.enzh.mp4?v=1793398746-22632026-10-08yes https://exercises.lol/videos/en_b2/advanced-passive2026-10-30https://exercises.lol/video-media/en_b2/advanced-passive/advanced-passive.thumb.jpg?v=1793392262English B2 · Advanced passiveYou know the B1 passive: the homework was eaten by the cat. B2 adds three grown-up moves. The get-passive: he got fired. The impersonal passive: it is said…https://exercises.lol/video-media/en_b2/advanced-passive/advanced-passive.enzh.mp4?v=1793392262-22402026-10-08yes https://exercises.lol/videos/en_b2/reported-questions-and-commands2026-10-30https://exercises.lol/video-media/en_b2/reported-questions-and-commands/reported-questions-and-commands.thumb.jpg?v=1793398763English B2 · Reported questions and commandsB1 taught you to report statements and questions. B2 adds commands, requests, advice and suggestions, everything people say to move other people. The memory…https://exercises.lol/video-media/en_b2/reported-questions-and-commands/reported-questions-and-commands.enzh.mp4?v=1793398763-22742026-10-08yes https://exercises.lol/videos/en_b2/past-modals2026-10-30https://exercises.lol/video-media/en_b2/past-modals/past-modals.thumb.jpg?v=1793392745English B2 · Past modalsModals talk about the present: it might rain. To talk about the past, English adds have plus the participle. The memory hook: the modal is a detective, and…https://exercises.lol/video-media/en_b2/past-modals/past-modals.enzh.mp4?v=1793392745-22432026-10-08yes https://exercises.lol/videos/en_b2/relative-clauses-defining-non-defining2026-10-30https://exercises.lol/video-media/en_b2/relative-clauses-defining-non-defining/relative-clauses-defining-non-defining.thumb.jpg?v=1793398578English B2 · Relative clauses: defining and non-definingB1 gave you the relative clause; B2 adds the comma question. Defining, no commas: the students who studied passed — only the studiers; the clause identifies…https://exercises.lol/video-media/en_b2/relative-clauses-defining-non-defining/relative-clauses-defining-non-defining.enzh.mp4?v=1793398578-22552026-10-08yes https://exercises.lol/videos/en_b2/the-causative2026-10-30https://exercises.lol/video-media/en_b2/the-causative/the-causative.thumb.jpg?v=1793392257English B2 · The causativeSometimes you don't do the work; you arrange for someone else to do it. The causative: have or get plus object plus past participle. I had my hair cut; a…https://exercises.lol/video-media/en_b2/the-causative/the-causative.enzh.mp4?v=1793392257-22182026-10-08yes https://exercises.lol/videos/en_b2/contrast-linkers2026-10-30https://exercises.lol/video-media/en_b2/contrast-linkers/contrast-linkers.thumb.jpg?v=1793398603English B2 · Contrast linkersContrast is the soul of argument, and English has a whole shelf of linkers that disagree politely. Although it rained, we played. Despite the rain, we played.…https://exercises.lol/video-media/en_b2/contrast-linkers/contrast-linkers.enzh.mp4?v=1793398603-22562026-10-08yes https://exercises.lol/videos/en_b2/listening-discussions-arguments-media2026-11-08https://exercises.lol/video-media/en_b2/listening-discussions-arguments-media/listening-discussions-arguments-media.thumb.jpg?v=1794117329English B2 · Listening: discussions, arguments and mediaB2 listening follows arguments, not just sentences. An argument is a spine: claim, reason, evidence, concession, and the claim restated stronger. Discourse…https://exercises.lol/video-media/en_b2/listening-discussions-arguments-media/listening-discussions-arguments-media.enzh.mp4?v=1794117329-22182026-10-28yes https://exercises.lol/videos/en_b2/reading-essays-reports-criticism2026-11-08https://exercises.lol/video-media/en_b2/reading-essays-reports-criticism/reading-essays-reports-criticism.thumb.jpg?v=1794115274English B2 · Reading: essays, reports and criticismB2 reading handles paid-writing shapes. The essay argues a case: thesis, counter-argument, reply. The report informs: findings under headings, with no visible…https://exercises.lol/video-media/en_b2/reading-essays-reports-criticism/reading-essays-reports-criticism.enzh.mp4?v=1794115274-22062026-10-28yes https://exercises.lol/videos/en_b2/speaking-arguing-presenting2026-11-08https://exercises.lol/video-media/en_b2/speaking-arguing-presenting/speaking-arguing-presenting.thumb.jpg?v=1794120728English B2 · Speaking: arguing a case and presentingB2 speaking takes the floor and holds it with structure. Arguing a case out loud runs four moves: state the claim, support it with a reason and a carried…https://exercises.lol/video-media/en_b2/speaking-arguing-presenting/speaking-arguing-presenting.enzh.mp4?v=1794120728-21812026-10-28yes https://exercises.lol/videos/en_b2/writing-proposal-objections2026-11-08https://exercises.lol/video-media/en_b2/writing-proposal-objections/writing-proposal-objections.thumb.jpg?v=1794115914English B2 · Writing: propose a change and weigh objectionsA B2 proposal does more than ask: it argues a change and stands ready for the objections. Five parts. The situation, the problem now. The proposal, the change…https://exercises.lol/video-media/en_b2/writing-proposal-objections/writing-proposal-objections.enzh.mp4?v=1794115914-22332026-10-28yes https://exercises.lol/videos/gac_business/business-decisions2026-10-30https://exercises.lol/video-media/gac_business/business-decisions/business-decisions.thumb.jpg?v=1793338557Business II: Explain Decisions with Evidence and AccountsBusiness II connects concepts to applied decisions. The existing notes introduce the business, its environment, planning, management, employment relations and…https://exercises.lol/video-media/gac_business/business-decisions/business-decisions.enzh.mp4?v=1793338557-215292026-10-02yes https://exercises.lol/videos/gac_business/personal-finance-and-entrepreneurship2026-10-29https://exercises.lol/video-media/gac_business/personal-finance-and-entrepreneurship/personal-finance-and-entrepreneurship.thumb.jpg?v=1793309295Personal Finance and Entrepreneurship: Budgets and a Feasible VentureThis module connects personal money decisions with planning a small venture. The original notes introduce budgeting, purchasing, credit, entrepreneurship…https://exercises.lol/video-media/gac_business/personal-finance-and-entrepreneurship/personal-finance-and-entrepreneurship.enzh.mp4?v=1793309295-213982026-10-02yes https://exercises.lol/videos/gac_business/international-business-decisions2026-11-08https://exercises.lol/video-media/gac_business/international-business-decisions/international-business-decisions.thumb.jpg?v=1794106994International Business: Cross-border Decisions and EvidenceInternational Business extends the earlier study of one firm to activity across borders. A stronger answer connects evidence to a judgement, rather than only…https://exercises.lol/video-media/gac_business/international-business-decisions/international-business-decisions.enzh.mp4?v=1794106994-213472026-10-02yes https://exercises.lol/videos/gac_computing/academic-computing2026-10-30https://exercises.lol/video-media/gac_computing/academic-computing/academic-computing.thumb.jpg?v=1793335078Computing I: Academic Documents and CollaborationA group researching school transport needs more than a finished-looking file. It needs usable tools, reliable sources, a clear argument and a record of how…https://exercises.lol/video-media/gac_computing/academic-computing/academic-computing.enzh.mp4?v=1793335078-212172026-10-02yes https://exercises.lol/videos/gac_computing/web-development2026-10-30https://exercises.lol/video-media/gac_computing/web-development/web-development.thumb.jpg?v=1793318673Computing II: Design, Build and Explain a WebsiteA school-transport website can help classmates understand the main result and inspect the study's method. A useful page needs a clear purpose, readable…https://exercises.lol/video-media/gac_computing/web-development/web-development.enzh.mp4?v=1793318673-213102026-10-02yes https://exercises.lol/videos/gac_computing/database-web-apps2026-10-29https://exercises.lol/video-media/gac_computing/database-web-apps/database-web-apps.thumb.jpg?v=1793317608Computing III: Build, Query and Explain a Database Web AppComputing III asks you to connect a website to data and use SQL to support decisions. Our practical question is which classes have places left. The records are…https://exercises.lol/video-media/gac_computing/database-web-apps/database-web-apps.enzh.mp4?v=1793317608-212712026-10-02yes https://exercises.lol/videos/gac_english/listening-and-speaking-practice2026-11-08https://exercises.lol/video-media/gac_english/listening-and-speaking-practice/listening-and-speaking-practice.thumb.jpg?v=1794107276GAC001 Academic English I: Listening and Speaking SkillsYou hear a change to a club meeting, explain a plan to classmates, or help a group choose a room. In each situation, useful English connects a message to an…https://exercises.lol/video-media/gac_english/listening-and-speaking-practice/listening-and-speaking-practice.enzh.mp4?v=1794107276-215582026-10-08yes https://exercises.lol/videos/gac_english/reading-and-writing-practice2026-11-08https://exercises.lol/video-media/gac_english/reading-and-writing-practice/reading-and-writing-practice.thumb.jpg?v=1794108134GAC002 Academic English I: Reading and Writing SkillsGAC zero zero two develops reading and writing skills through communicating, culture, leisure, travel, living things and technology. The skills include…https://exercises.lol/video-media/gac_english/reading-and-writing-practice/reading-and-writing-practice.enzh.mp4?v=1794108134-213602026-10-08yes https://exercises.lol/videos/gac_english/listening-and-speaking-ii2026-11-08https://exercises.lol/video-media/gac_english/listening-and-speaking-ii/listening-and-speaking-ii.thumb.jpg?v=1794106995GAC007 Academic English II: Listening and Speaking SkillsGAC zero zero seven develops listening and speaking through comparing spoken text types, applying listening strategies, taking notes and summarising…https://exercises.lol/video-media/gac_english/listening-and-speaking-ii/listening-and-speaking-ii.enzh.mp4?v=1794106995-211312026-10-08yes https://exercises.lol/videos/gac_english/reading-and-writing-ii2026-10-29https://exercises.lol/video-media/gac_english/reading-and-writing-ii/reading-and-writing-ii.thumb.jpg?v=1793299867GAC008 Academic English II: Reading and Writing SkillsThis GAC zero zero eight aligned lesson develops researched writing. Read arguments, evaluate sources, join ideas accurately and keep borrowed material…https://exercises.lol/video-media/gac_english/reading-and-writing-ii/reading-and-writing-ii.enzh.mp4?v=1793299867-25552026-10-08yes https://exercises.lol/videos/gac_english/seminars-and-critical-listening2026-11-08https://exercises.lol/video-media/gac_english/seminars-and-critical-listening/seminars-and-critical-listening.thumb.jpg?v=1794106872GAC014 Academic English III: Listening & Speaking SkillsGAC zero one four develops critical listening, academic interaction, evaluation of arguments, oral presentations using relevant media, and formal class…https://exercises.lol/video-media/gac_english/seminars-and-critical-listening/seminars-and-critical-listening.enzh.mp4?v=1794106872-212572026-10-08yes https://exercises.lol/videos/gac_english/critical-reading-and-the-essay2026-11-08https://exercises.lol/video-media/gac_english/critical-reading-and-the-essay/critical-reading-and-the-essay.thumb.jpg?v=1794108059GAC015 Academic English III: Reading & Writing SkillsGAC zero one five develops critical reading and writing, selection and evaluation of sources, logical arguments, annotated bibliography work, information…https://exercises.lol/video-media/gac_english/critical-reading-and-the-essay/critical-reading-and-the-essay.enzh.mp4?v=1794108059-211962026-10-08yes https://exercises.lol/videos/gac_mathematics/core-skills-original-practice2026-10-28https://exercises.lol/video-media/gac_mathematics/core-skills-original-practice/core-skills-original-practice.thumb.jpg?v=1793200801Worked PracticeHere is the map for this practice pack. Four questions, each tied to a sheet you already know: Q1 and Q2 belong to sheet one point one, Q3 to sheet one point…https://exercises.lol/video-media/gac_mathematics/core-skills-original-practice/core-skills-original-practice.enzh.mp4?v=1793200801-27852026-10-03yes https://exercises.lol/videos/gac_mathematics/probability-statistics-finance2026-10-30https://exercises.lol/video-media/gac_mathematics/probability-statistics-finance/probability-statistics-finance.thumb.jpg?v=1793400413GAC010 Mathematics II: Probability, Statistics and FinanceA cheaper headline rate need not produce the cheaper total, and a larger survey need not produce a more representative result. Mathematics two uses explicit…https://exercises.lol/video-media/gac_mathematics/probability-statistics-finance/probability-statistics-finance.enzh.mp4?v=1793400413-215412026-10-08yes https://exercises.lol/videos/gac_mathematics/differentiation-and-integration2026-10-28https://exercises.lol/video-media/gac_mathematics/differentiation-and-integration/differentiation-and-integration.thumb.jpg?v=1793204046GAC016 Mathematics III: CalculusAn average speed does not tell you every instantaneous speed, and a signed displacement does not always equal total distance. Calculus makes those distinctions…https://exercises.lol/video-media/gac_mathematics/differentiation-and-integration/differentiation-and-integration.enzh.mp4?v=1793204046-26892026-10-08yes https://exercises.lol/videos/gac_mathematics/discrete-mathematics2026-10-30https://exercises.lol/video-media/gac_mathematics/discrete-mathematics/discrete-mathematics.thumb.jpg?v=1793400030GAC024 Discrete MathematicsA repeated set member is counted once, a binary carry may exceed a fixed width, and the fewest-edge route may not have the smallest weight. Discrete…https://exercises.lol/video-media/gac_mathematics/discrete-mathematics/discrete-mathematics.enzh.mp4?v=1793400030-29982026-10-08yes https://exercises.lol/videos/gac_psychology/introduction-to-psychology2026-10-29https://exercises.lol/video-media/gac_psychology/introduction-to-psychology/introduction-to-psychology.thumb.jpg?v=1793294964Psychology: Evidence, Experience and BehaviourImagine a student revising quietly until a phone alert arrives. The student checks the phone and loses their place. We can ask about attention, rewards from…https://exercises.lol/video-media/gac_psychology/introduction-to-psychology/introduction-to-psychology.enzh.mp4?v=1793294964-213462026-10-02yes https://exercises.lol/videos/gac_psychology/research-in-psychology2026-10-29https://exercises.lol/video-media/gac_psychology/research-in-psychology/research-in-psychology.thumb.jpg?v=1793308966Psychology Research, Learning and Social BehaviourStudents who report more sleep may also have higher grades. Does that establish that sleep caused the difference? Sleep might influence performance, stress…https://exercises.lol/video-media/gac_psychology/research-in-psychology/research-in-psychology.enzh.mp4?v=1793308966-212202026-10-02yes https://exercises.lol/videos/gac_science/scientific-principles2026-11-08https://exercises.lol/video-media/gac_science/scientific-principles/scientific-principles.thumb.jpg?v=1794106980Scientific Principles: Evidence, Measurement and ReportsImagine comparing two paper samples and finding that one holds more water. Does that establish which product is best for every cleaning task? No. First ask how…https://exercises.lol/video-media/gac_science/scientific-principles/scientific-principles.enzh.mp4?v=1794106980-212312026-10-02yes https://exercises.lol/videos/gac_science/general-science2026-10-29https://exercises.lol/video-media/gac_science/general-science/general-science.thumb.jpg?v=1793294967General Science: Living Systems, Materials, Waves and EvidenceImagine a pond beside a school. You see plants, water and a label describing a treatment. What can you establish from those observations? Plants do not prove…https://exercises.lol/video-media/gac_science/general-science/general-science.enzh.mp4?v=1793294967-215882026-10-02yes https://exercises.lol/videos/gac_social_science/identity-and-interaction2026-10-29https://exercises.lol/video-media/gac_social_science/identity-and-interaction/identity-and-interaction.thumb.jpg?v=1793318001Identity and Interaction: Communities, Research and EvidenceTwo club members miss an online discussion. One observer calls them uninterested; another asks whether they could use the platform. Those explanations suggest…https://exercises.lol/video-media/gac_social_science/identity-and-interaction/identity-and-interaction.enzh.mp4?v=1793318001-210622026-10-02yes https://exercises.lol/videos/gac_social_science/research-and-global-issues2026-10-29https://exercises.lol/video-media/gac_social_science/research-and-global-issues/research-and-global-issues.thumb.jpg?v=1793310627Global Issues: Research, Evidence and Group DecisionsA school counts food waste and asks students why they leave food. The counts describe an amount, while the answers describe reported reasons. A useful report…https://exercises.lol/video-media/gac_social_science/research-and-global-issues/research-and-global-issues.enzh.mp4?v=1793310627-214642026-10-02yes https://exercises.lol/videos/gac_study_skills/independent-learning2026-10-29https://exercises.lol/video-media/gac_study_skills/independent-learning/independent-learning.thumb.jpg?v=1793293757Study Skills for Independent LearningImagine that you have finished an assignment and written, I kept a journal. That tells us what you did, but little about what you learned. A more useful record…https://exercises.lol/video-media/gac_study_skills/independent-learning/independent-learning.enzh.mp4?v=1793293757-210532026-10-02yes https://exercises.lol/videos/gac_study_skills/interpersonal-communication2026-10-29https://exercises.lol/video-media/gac_study_skills/interpersonal-communication/interpersonal-communication.thumb.jpg?v=1793311471Interpersonal Communication and TeamsImagine a meeting where a teammate has brought a survey table but says nothing. Does silence prove that the teammate has nothing useful to contribute? No. A…https://exercises.lol/video-media/gac_study_skills/interpersonal-communication/interpersonal-communication.enzh.mp4?v=1793311471-27552026-10-02yes https://exercises.lol/videos/gac_study_skills/social-emotional-project2026-10-30https://exercises.lol/video-media/gac_study_skills/social-emotional-project/social-emotional-project.thumb.jpg?v=1793318750Social and Emotional Learning through a School ProjectA project about school waste can become more than an essay with slides if someone actually uses what you make. GAC zero three one aligned practice develops…https://exercises.lol/video-media/gac_study_skills/social-emotional-project/social-emotional-project.enzh.mp4?v=1793318750-23872026-10-02yes https://exercises.lol/videos/gac_study_skills/education-career-pathway2026-10-30https://exercises.lol/video-media/gac_study_skills/education-career-pathway/education-career-pathway.thumb.jpg?v=1793322628Education and Career PathwaysDesigning your next step begins with evidence of what you are interested in and what you can do, then courses that fit. GAC zero three two aligned support…https://exercises.lol/video-media/gac_study_skills/education-career-pathway/education-career-pathway.enzh.mp4?v=1793322628-23172026-10-02yes https://exercises.lol/videos/gac_study_skills/research-proposal2026-10-29https://exercises.lol/video-media/gac_study_skills/research-proposal/research-proposal.thumb.jpg?v=1793306288Develop and Defend a Research ProposalGAC zero three three aligned practice develops a research proposal in a team. You develop, present and defend a plan, with presentation and coursework…https://exercises.lol/video-media/gac_study_skills/research-proposal/research-proposal.enzh.mp4?v=1793306288-24652026-10-02yes https://exercises.lol/videos/gre_general/topic-012026-11-08https://exercises.lol/video-media/gre_general/topic-01/topic-01.thumb.jpg?v=1794117415Verbal: reading and argument structureIn 1965 the British medical statistician Austin Bradford Hill gave a lecture in London called "The Environment and Disease: Association or Causation?". Hill…https://exercises.lol/video-media/gre_general/topic-01/topic-01.enzh.mp4?v=1794117415-23642026-10-28yes https://exercises.lol/videos/gre_general/topic-022026-10-30https://exercises.lol/video-media/gre_general/topic-02/topic-02.thumb.jpg?v=1793395554Verbal: text completion and sentence equivalenceThis unit completes one-, two- and three-blank passages from context, selects two sentence-equivalence choices that give coherent equivalent meanings, and uses…https://exercises.lol/video-media/gre_general/topic-02/topic-02.enzh.mp4?v=1793395554-21242026-10-28yes https://exercises.lol/videos/gre_general/topic-032026-11-08https://exercises.lol/video-media/gre_general/topic-03/topic-03.thumb.jpg?v=1794124887Quantitative comparison and number reasoningIn 1202 Leonardo of Pisa, later known as Fibonacci, published Liber Abaci ("The Book of Calculation"). He had learnt the Hindu–Arabic numerals as a boy in…https://exercises.lol/video-media/gre_general/topic-03/topic-03.enzh.mp4?v=1794124887-23892026-10-28yes https://exercises.lol/videos/gre_general/topic-042026-11-08https://exercises.lol/video-media/gre_general/topic-04/topic-04.thumb.jpg?v=1794117545Quantitative problem solving and dataIn 1763, two years after the death of the English minister Thomas Bayes, his friend Richard Price sent the Royal Society an essay he had found among Bayes's…https://exercises.lol/video-media/gre_general/topic-04/topic-04.enzh.mp4?v=1794117545-23672026-10-28yes https://exercises.lol/videos/gre_general/topic-052026-10-30https://exercises.lol/video-media/gre_general/topic-05/topic-05.thumb.jpg?v=1793395539Analytical Writing: Analyze an IssueThis unit develops a focused response to the specific Issue instruction, uses reasons, examples and qualifications, and organises and revises analytical…https://exercises.lol/video-media/gre_general/topic-05/topic-05.enzh.mp4?v=1793395539-21172026-10-28yes https://exercises.lol/videos/gre_general/topic-062026-11-08https://exercises.lol/video-media/gre_general/topic-06/topic-06.thumb.jpg?v=1794117599Text completion: dependent meanings across two and three blanksIn 1952 Michael Ventris, a 30-year-old English architect, deciphered Linear B, a script found on clay tablets at Knossos in Crete and at Pylos in Greece.…https://exercises.lol/video-media/gre_general/topic-06/topic-06.enzh.mp4?v=1794117599-23882026-10-28yes https://exercises.lol/videos/gre_general/topic-072026-11-08https://exercises.lol/video-media/gre_general/topic-07/topic-07.thumb.jpg?v=1794117627Sentence equivalence: fitting context and matching complete meaningsIn 1852 the London doctor Peter Mark Roget, then aged 73, published his Thesaurus of English Words and Phrases. He had started the lists as a young man to help…https://exercises.lol/video-media/gre_general/topic-07/topic-07.enzh.mp4?v=1794117627-23502026-10-28yes https://exercises.lol/videos/gre_general/topic-082026-10-30https://exercises.lol/video-media/gre_general/topic-08/topic-08.thumb.jpg?v=1793395587Reading comprehension: independent option tests and sentence selectionThis unit evaluates each of three select-all options against the passage, locates the sentence that does the exact requested job, and distinguishes a supported…https://exercises.lol/video-media/gre_general/topic-08/topic-08.enzh.mp4?v=1793395587-21422026-10-28yes https://exercises.lol/videos/gre_general/topic-092026-10-30https://exercises.lol/video-media/gre_general/topic-09/topic-09.thumb.jpg?v=1793395903Verbal arguments: assumptions, alternative causes and evidence directionThis unit separates observations, assumptions and conclusions, chooses evidence that strengthens or weakens the precise argument, and uses an assumption's…https://exercises.lol/video-media/gre_general/topic-09/topic-09.enzh.mp4?v=1793395903-21342026-10-28yes https://exercises.lol/videos/gre_general/topic-102026-11-08https://exercises.lol/video-media/gre_general/topic-10/topic-10.thumb.jpg?v=1794117707Quantitative response formats: all valid values and numerical entryIn about AD 250 Diophantus of Alexandria wrote Arithmetica, a collection of problems asking for the numbers that satisfy given conditions. Around 1637 the…https://exercises.lol/video-media/gre_general/topic-10/topic-10.enzh.mp4?v=1794117707-23962026-10-28yes https://exercises.lol/videos/gre_general/topic-112026-11-08https://exercises.lol/video-media/gre_general/topic-11/topic-11.thumb.jpg?v=1794117824Arithmetic: divisibility, remainders and multiplicative changeIn 1801 the 24-year-old Carl Friedrich Gauss published Disquisitiones Arithmeticae ("Arithmetical Investigations"). On its first pages he introduced the sign…https://exercises.lol/video-media/gre_general/topic-11/topic-11.enzh.mp4?v=1794117824-24362026-10-28yes https://exercises.lol/videos/gre_general/topic-122026-11-08https://exercises.lol/video-media/gre_general/topic-12/topic-12.thumb.jpg?v=1794121415Algebra: domains, systems, inequalities and functionsIn 1591 the French lawyer François Viète, who also broke Spanish codes for King Henri IV, published In artem analyticem isagoge ("Introduction to the Analytic…https://exercises.lol/video-media/gre_general/topic-12/topic-12.enzh.mp4?v=1794121415-24502026-10-28yes https://exercises.lol/videos/gre_general/topic-132026-11-08https://exercises.lol/video-media/gre_general/topic-13/topic-13.thumb.jpg?v=1794117588Geometry: labelled facts, coordinates, circles and solidsIn 1899 the German mathematician David Hilbert published Grundlagen der Geometrie ("Foundations of Geometry"). He rebuilt Euclid's geometry so that every…https://exercises.lol/video-media/gre_general/topic-13/topic-13.enzh.mp4?v=1794117588-24232026-10-28yes https://exercises.lol/videos/gre_general/topic-142026-11-08https://exercises.lol/video-media/gre_general/topic-14/topic-14.thumb.jpg?v=1794117621Data analysis: spread, weighted averages and conditional probabilityIn the autumn of 1973 the University of California, Berkeley, admitted about 44% of the men who applied to its graduate programmes but only about 35% of the…https://exercises.lol/video-media/gre_general/topic-14/topic-14.enzh.mp4?v=1794117621-24192026-10-28yes https://exercises.lol/videos/gre_general/topic-152026-11-08https://exercises.lol/video-media/gre_general/topic-15/topic-15.thumb.jpg?v=1794117782Analyze an Issue: instruction families and a reasoned qualified positionBetween October 1787 and May 1788, three men writing as "Publius", Alexander Hamilton, James Madison and John Jay, published 85 essays in New York newspapers…https://exercises.lol/video-media/gre_general/topic-15/topic-15.enzh.mp4?v=1794117782-26032026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-012026-11-08https://exercises.lol/video-media/gre_mathematics/topic-01/topic-01.thumb.jpg?v=1794122536C.1 · Single-variable calculus and applicationsIn 1684 Gottfried Leibniz published a six-page paper with rules for differentiating sums, products and quotients, using the dx notation still used today. Isaac…https://exercises.lol/video-media/gre_mathematics/topic-01/topic-01.enzh.mp4?v=1794122536-24022026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-022026-11-08https://exercises.lol/video-media/gre_mathematics/topic-02/topic-02.thumb.jpg?v=1794117894C.2 · Multivariable calculus and vector analysisIn 1881 Josiah Willard Gibbs, a physics professor at Yale, printed a short pamphlet for his students called Elements of Vector Analysis. He replaced the…https://exercises.lol/video-media/gre_mathematics/topic-02/topic-02.enzh.mp4?v=1794117894-23242026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-032026-11-08https://exercises.lol/video-media/gre_mathematics/topic-03/topic-03.thumb.jpg?v=1794117949A.1 · Linear algebraIn 1998 two Stanford graduate students, Sergey Brin and Larry Page, described a way to rank web pages. A page is important if important pages link to it.…https://exercises.lol/video-media/gre_mathematics/topic-03/topic-03.enzh.mp4?v=1794117949-23672026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-042026-11-08https://exercises.lol/video-media/gre_mathematics/topic-04/topic-04.thumb.jpg?v=1794117965A.2 · Abstract algebra and number theoryOn the night of 29 May 1832 Évariste Galois, aged 20, sat up in Paris writing a letter to a friend, summarising his mathematical discoveries in case he died.…https://exercises.lol/video-media/gre_mathematics/topic-04/topic-04.enzh.mp4?v=1794117965-23362026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-052026-11-08https://exercises.lol/video-media/gre_mathematics/topic-05/topic-05.thumb.jpg?v=1794117950T.1 · Real analysis and topologyIn 1872 Karl Weierstrass presented to the Berlin Academy a function that is continuous everywhere but has a derivative nowhere: its graph is a jagged curve…https://exercises.lol/video-media/gre_mathematics/topic-05/topic-05.enzh.mp4?v=1794117950-23482026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-062026-11-08https://exercises.lol/video-media/gre_mathematics/topic-06/topic-06.thumb.jpg?v=1794117992T.2 · Discrete mathematics, probability and numerical methodsIn 1654 a French gambler, the Chevalier de Méré, noticed something odd. Betting on at least one six in four rolls of a die won slightly more often than it…https://exercises.lol/video-media/gre_mathematics/topic-06/topic-06.enzh.mp4?v=1794117992-23952026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-072026-11-08https://exercises.lol/video-media/gre_mathematics/topic-07/topic-07.thumb.jpg?v=1794123094T.3 · Complex analysis and residuesIn 1545 Gerolamo Cardano published a formula for solving cubic equations. For some equations with three real roots, such as x^3 = 15x + 4, the formula needed…https://exercises.lol/video-media/gre_mathematics/topic-07/topic-07.enzh.mp4?v=1794123094-23422026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-082026-11-08https://exercises.lol/video-media/gre_mathematics/topic-08/topic-08.thumb.jpg?v=1794121451C.3 · Differential equations and initial conditionsIn 1701 Isaac Newton published, without his name, a short paper on heat. He heated an iron block in a fire, set it to cool in a steady wind, and recorded its…https://exercises.lol/video-media/gre_mathematics/topic-08/topic-08.enzh.mp4?v=1794121451-23932026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-092026-11-08https://exercises.lol/video-media/gre_mathematics/topic-09/topic-09.thumb.jpg?v=1794118049A.3 · Groups, cosets and quotient mapsIn 1974 Ernő Rubik, a design teacher in Budapest, built a cube of 26 small blocks that could twist on every face. Its positions form a group, with about 4.3…https://exercises.lol/video-media/gre_mathematics/topic-09/topic-09.enzh.mp4?v=1794118049-23802026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-102026-11-08https://exercises.lol/video-media/gre_mathematics/topic-10/topic-10.thumb.jpg?v=1794118069A.4 · Rings, ideals and modulesIn March 1847 Gabriel Lamé announced to the Paris Academy that he had proved Fermat's Last Theorem. His proof factored numbers of the form x^n + y^n using…https://exercises.lol/video-media/gre_mathematics/topic-10/topic-10.enzh.mp4?v=1794118069-23302026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-112026-11-08https://exercises.lol/video-media/gre_mathematics/topic-11/topic-11.thumb.jpg?v=1794118001A.5 · Polynomials and field extensionsOn 30 March 1796 Carl Friedrich Gauss, aged 18, found that a regular polygon with 17 sides can be drawn with only a straightedge and compass, something no one…https://exercises.lol/video-media/gre_mathematics/topic-11/topic-11.enzh.mp4?v=1794118001-23482026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-122026-11-08https://exercises.lol/video-media/gre_mathematics/topic-12/topic-12.thumb.jpg?v=1794118071A.6 · Congruences, divisibility and arithmetic functionsIn August 1977 Martin Gardner's column in Scientific American printed a message encrypted with a new method, RSA, invented that year by Ron Rivest, Adi Shamir…https://exercises.lol/video-media/gre_mathematics/topic-12/topic-12.enzh.mp4?v=1794118071-23362026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-132026-11-08https://exercises.lol/video-media/gre_mathematics/topic-13/topic-13.thumb.jpg?v=1794118264T.4 · Sequences, series and uniform convergenceIn his famous 1821 textbook, Augustin-Louis Cauchy stated that a convergent series of continuous functions has a continuous sum. In 1826 the young Norwegian…https://exercises.lol/video-media/gre_mathematics/topic-13/topic-13.enzh.mp4?v=1794118264-23512026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-142026-11-08https://exercises.lol/video-media/gre_mathematics/topic-14/topic-14.thumb.jpg?v=1794122485T.5 · Open sets, compactness and connectednessIn 1883 Georg Cantor described a set built by a simple rule. Start with [0, 1], remove the open middle third, then remove the middle third of each remaining…https://exercises.lol/video-media/gre_mathematics/topic-14/topic-14.enzh.mp4?v=1794122485-23342026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-152026-11-08https://exercises.lol/video-media/gre_mathematics/topic-15/topic-15.thumb.jpg?v=1794118470C.4 · Taylor expansions and power-series endpointsAround 1400, in Kerala in southern India, the astronomer Madhava of Sangamagrama found an infinite series for pi : along with series for sine and cosine, more…https://exercises.lol/video-media/gre_mathematics/topic-15/topic-15.enzh.mp4?v=1794118470-23752026-10-29yes https://exercises.lol/videos/gre_mathematics/topic-162026-10-30https://exercises.lol/video-media/gre_mathematics/topic-16/topic-16.thumb.jpg?v=1793395972C.5 · Improper integrals and geometric applicationsThis unit defines improper integrals by limits at each singular boundary, selects area, volume and arc-length formulas from the geometry, and separates…https://exercises.lol/video-media/gre_mathematics/topic-16/topic-16.enzh.mp4?v=1793395972-21752026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-172026-11-08https://exercises.lol/video-media/gre_mathematics/topic-17/topic-17.thumb.jpg?v=1794118378C.6 · Multivariable extrema and constrained optimisationIn 1613 Johannes Kepler bought wine for his wedding and watched the merchant measure each barrel's volume with a single rod pushed diagonally through the bung…https://exercises.lol/video-media/gre_mathematics/topic-17/topic-17.enzh.mp4?v=1794118378-23212026-10-29yes https://exercises.lol/videos/gre_mathematics/topic-182026-11-08https://exercises.lol/video-media/gre_mathematics/topic-18/topic-18.thumb.jpg?v=1794118442C.7 · Coordinate changes and vector integral theoremsIn 1828 George Green, a self-taught miller from Nottingham with about a year of school, paid for the printing of An Essay on the Application of Mathematical…https://exercises.lol/video-media/gre_mathematics/topic-18/topic-18.enzh.mp4?v=1794118442-23332026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-192026-11-08https://exercises.lol/video-media/gre_mathematics/topic-19/topic-19.thumb.jpg?v=1794118446T.6 · Functions, inverse branches and compositionIn 1837 Peter Gustav Lejeune Dirichlet gave the modern idea of a function: any rule that assigns to each input exactly one output, whether or not a formula…https://exercises.lol/video-media/gre_mathematics/topic-19/topic-19.enzh.mp4?v=1794118446-23402026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-202026-10-29https://exercises.lol/video-media/gre_mathematics/topic-20/topic-20.thumb.jpg?v=1793254044T.7 · Set images, equivalence relations and logical negationThis unit proves image identities and distinguishes inclusion from equality, checks reflexivity, symmetry and transitivity with explicit cases, and negates…https://exercises.lol/video-media/gre_mathematics/topic-20/topic-20.enzh.mp4?v=1793254044-21842026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-212026-10-29https://exercises.lol/video-media/gre_mathematics/topic-21/topic-21.thumb.jpg?v=1793284196T.8 · Conditioning, Bayesian inference and sampling errorThis unit separates conditional, joint and independent-event probabilities, calculates posterior probabilities with a complete base-rate table, and uses…https://exercises.lol/video-media/gre_mathematics/topic-21/topic-21.enzh.mp4?v=1793284196-21932026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-222026-10-29https://exercises.lol/video-media/gre_mathematics/topic-22/topic-22.thumb.jpg?v=1793284205T.9 · Similarity, scaling and conic distance lociThis unit matches triangle vertices by equal angles before forming a side ratio, applies length, area and volume scale factors, and identifies conic distance…https://exercises.lol/video-media/gre_mathematics/topic-22/topic-22.enzh.mp4?v=1793284205-21862026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-232026-10-29https://exercises.lol/video-media/gre_mathematics/topic-23/topic-23.thumb.jpg?v=1793284421C.8 · Trigonometric phase and parametric curvesThis unit distinguishes amplitude, angular frequency, phase angle and horizontal shift; eliminates a parameter while keeping its domain and direction; and uses…https://exercises.lol/video-media/gre_mathematics/topic-23/topic-23.enzh.mp4?v=1793284421-21972026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-242026-11-08https://exercises.lol/video-media/gre_mathematics/topic-24/topic-24.thumb.jpg?v=1794118495T.10 · Vector geometry, projections and oriented areaOn 16 October 1843 William Rowan Hamilton was walking along the Royal Canal in Dublin when he suddenly saw how to multiply three-dimensional quantities. He cut…https://exercises.lol/video-media/gre_mathematics/topic-24/topic-24.enzh.mp4?v=1794118495-23602026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-252026-11-08https://exercises.lol/video-media/gre_mathematics/topic-25/topic-25.thumb.jpg?v=1794118495C.9 · Integrating factors and nonhomogeneous differential equationsOn 10 June 2000 thousands of people walked across London's new Millennium Bridge on its opening day. The bridge began to sway from side to side. Walkers…https://exercises.lol/video-media/gre_mathematics/topic-25/topic-25.enzh.mp4?v=1794118495-23532026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-262026-10-29https://exercises.lol/video-media/gre_mathematics/topic-26/topic-26.thumb.jpg?v=1793255126T.11 · Weak compositions, loop invariants and flowchart tracingThis unit counts indistinguishable allocations with nonnegative or positive constraints, traces a flowchart in statement order with correct resets, and uses a…https://exercises.lol/video-media/gre_mathematics/topic-26/topic-26.enzh.mp4?v=1793255126-21812026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-272026-10-29https://exercises.lol/video-media/gre_mathematics/topic-27/topic-27.thumb.jpg?v=1793255280C.10 · Implicit differentiation and the inverse JacobianThis unit differentiates a coupled implicit system as a linear system, uses a nonzero Jacobian determinant to justify a local inverse, and distinguishes…https://exercises.lol/video-media/gre_mathematics/topic-27/topic-27.enzh.mp4?v=1793255280-21912026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-282026-11-08https://exercises.lol/video-media/gre_mathematics/topic-28/topic-28.thumb.jpg?v=1794118505A.7 · LU factorisation and nullity of composed mapsIn 1948 Alan Turing, working on the first electronic computers in Britain, wrote a paper on how rounding errors grow when large linear systems are solved by…https://exercises.lol/video-media/gre_mathematics/topic-28/topic-28.enzh.mp4?v=1794118505-23152026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-292026-11-08https://exercises.lol/video-media/gre_mathematics/topic-29/topic-29.thumb.jpg?v=1794127533C.11 · Integration by parts, order reversal and symmetryIn 1907 Guido Fubini, in Genoa, proved when the order of a double integral can be swapped. The condition matters. For f(x, y) = x^2 - y^2 over (x^2 + y^2)^2 on…https://exercises.lol/video-media/gre_mathematics/topic-29/topic-29.enzh.mp4?v=1794127533-23412026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-302026-11-08https://exercises.lol/video-media/gre_mathematics/topic-30/topic-30.thumb.jpg?v=1794118954C.12 · Related rates and removable quotient limitsIn 1643 Evangelista Torricelli found that water leaves a hole near the bottom of a tank at the speed it would reach falling freely from the water surface: v =…https://exercises.lol/video-media/gre_mathematics/topic-30/topic-30.enzh.mp4?v=1794118954-23092026-10-28yes https://exercises.lol/videos/gre_mathematics/topic-312026-10-30https://exercises.lol/video-media/gre_mathematics/topic-31/topic-31.thumb.jpg?v=1793395994T.12 · Metric completeness and closure from a basisThis unit checks a pullback metric using its defining map, decides completeness through the image of an isometry, and determines closure using every basic…https://exercises.lol/video-media/gre_mathematics/topic-31/topic-31.enzh.mp4?v=1793395994-21632026-10-28yes https://exercises.lol/videos/gre_physics/physics-012026-11-08https://exercises.lol/video-media/gre_physics/physics-01/physics-01.thumb.jpg?v=1794119484Classical mechanicsIn 1666 Isaac Newton compared the falling apple with the Moon. The Moon is about 60 Earth radii away (r = 3.84 times 10^8 m) and goes round once in 27.3 days…https://exercises.lol/video-media/gre_physics/physics-01/physics-01.enzh.mp4?v=1794119484-25182026-10-28yes https://exercises.lol/videos/gre_physics/physics-022026-10-29https://exercises.lol/video-media/gre_physics/physics-02/physics-02.thumb.jpg?v=1793256112ElectromagnetismZero electric potential at a point does not mean zero electric field there: the field depends on how the potential changes, not on its value. This topic covers…https://exercises.lol/video-media/gre_physics/physics-02/physics-02.enzh.mp4?v=1793256112-22542026-10-28yes https://exercises.lol/videos/gre_physics/physics-032026-10-29https://exercises.lol/video-media/gre_physics/physics-03/physics-03.thumb.jpg?v=1793256281Waves and opticsTwo individually bright waves can cancel at a point if their phases are opposite: crest meets trough. This topic covers superposition and interference…https://exercises.lol/video-media/gre_physics/physics-03/physics-03.enzh.mp4?v=1793256281-22282026-10-28yes https://exercises.lol/videos/gre_physics/physics-042026-11-08https://exercises.lol/video-media/gre_physics/physics-04/physics-04.thumb.jpg?v=1794119045Thermodynamics and statistical mechanicsIn 1824 the French engineer Sadi Carnot published Reflections on the Motive Power of Fire. Steam engines then turned only a few per cent of their heat into…https://exercises.lol/video-media/gre_physics/physics-04/physics-04.enzh.mp4?v=1794119045-24582026-10-28yes https://exercises.lol/videos/gre_physics/physics-052026-11-08https://exercises.lol/video-media/gre_physics/physics-05/physics-05.thumb.jpg?v=1794119790Quantum mechanics and atomic physicsIn 1927 Clinton Davisson and Lester Germer fired a beam of 54 eV electrons at a nickel crystal. Most scattered weakly in all directions, but at 50° they found…https://exercises.lol/video-media/gre_physics/physics-05/physics-05.enzh.mp4?v=1794119790-24452026-10-28yes https://exercises.lol/videos/gre_physics/physics-062026-11-08https://exercises.lol/video-media/gre_physics/physics-06/physics-06.thumb.jpg?v=1794125345Relativity, laboratory methods and specialised topicsIn October 1971 Joseph Hafele and Richard Keating flew four caesium atomic clocks round the world on ordinary airliners, first eastward and then westward.…https://exercises.lol/video-media/gre_physics/physics-06/physics-06.enzh.mp4?v=1794125345-24122026-10-28yes https://exercises.lol/videos/gre_physics/physics-072026-11-08https://exercises.lol/video-media/gre_physics/physics-07/physics-07.thumb.jpg?v=1794119054Atomic spectra and selection rulesIn 1885 Johann Balmer, a Swiss schoolteacher, looked at the wavelengths of the four visible lines of hydrogen measured by Anders Ångström. He found that one…https://exercises.lol/video-media/gre_physics/physics-07/physics-07.enzh.mp4?v=1794119054-24752026-10-28yes https://exercises.lol/videos/gre_physics/physics-082026-11-08https://exercises.lol/video-media/gre_physics/physics-08/physics-08.thumb.jpg?v=1794119001Solid-state, nuclear and particle modelsIn December 1947 John Bardeen and Walter Brattain, at Bell Laboratories, pressed two gold contacts very close together onto a small slab of germanium. A weak…https://exercises.lol/video-media/gre_physics/physics-08/physics-08.enzh.mp4?v=1794119001-24392026-10-28yes https://exercises.lol/videos/gre_physics/physics-092026-10-29https://exercises.lol/video-media/gre_physics/physics-09/physics-09.thumb.jpg?v=1793257313Hamiltonian mechanics and astrophysical scalingEnergy methods connect a spring oscillator and an orbit, but their coordinates and assumptions differ. This topic builds simple Hamiltonians, uses Hamilton's…https://exercises.lol/video-media/gre_physics/physics-09/physics-09.enzh.mp4?v=1793257313-22972026-10-28yes https://exercises.lol/videos/gre_physics/physics-102026-11-08https://exercises.lol/video-media/gre_physics/physics-10/physics-10.thumb.jpg?v=1794119076Collisions, work and oscillator energyIn 1668 the Royal Society in London asked for the laws of colliding bodies. Three answers arrived: from John Wallis, Christopher Wren and Christiaan Huygens.…https://exercises.lol/video-media/gre_physics/physics-10/physics-10.enzh.mp4?v=1794119076-24032026-10-28yes https://exercises.lol/videos/gre_physics/physics-112026-10-29https://exercises.lol/video-media/gre_physics/physics-11/physics-11.thumb.jpg?v=1793257762Rotation, buoyancy and terminal-speed balancesTurning a floating block upside down can change how much wood is submerged, even though the total weight stays the same. This topic uses pivot torque and…https://exercises.lol/video-media/gre_physics/physics-11/physics-11.enzh.mp4?v=1793257762-23352026-10-28yes https://exercises.lol/videos/gre_physics/physics-122026-11-08https://exercises.lol/video-media/gre_physics/physics-12/physics-12.thumb.jpg?v=1794119389Coupled acceleration and relative motionIn 1784 George Atwood, a Cambridge lecturer, described a machine for showing Newton's laws. Two nearly equal masses hung from a light pulley on one string.…https://exercises.lol/video-media/gre_physics/physics-12/physics-12.enzh.mp4?v=1794119389-24162026-10-28yes https://exercises.lol/videos/gre_physics/physics-132026-11-08https://exercises.lol/video-media/gre_physics/physics-13/physics-13.thumb.jpg?v=1794126415Electrostatic superposition, flux and conductorsIn 1785 Charles-Augustin de Coulomb hung a light rod from a thin silver wire, with a small charged ball on one end. When he brought another charged ball near…https://exercises.lol/video-media/gre_physics/physics-13/physics-13.enzh.mp4?v=1794126415-24052026-10-28yes https://exercises.lol/videos/gre_physics/physics-142026-10-29https://exercises.lol/video-media/gre_physics/physics-14/physics-14.thumb.jpg?v=1793258358Circuit power, induction and charged-particle motionA resistor in a parallel branch sees the branch voltage, which can differ from the battery voltage because another resistor is in series. This topic solves…https://exercises.lol/video-media/gre_physics/physics-14/physics-14.enzh.mp4?v=1793258358-23732026-10-28yes https://exercises.lol/videos/gre_physics/physics-152026-11-08https://exercises.lol/video-media/gre_physics/physics-15/physics-15.thumb.jpg?v=1794119438Maxwell waves, energy flow and boundary conditionsIn 1862 James Clerk Maxwell worked out the speed of waves in his model of electric and magnetic fields. It depended only on electrical constants that Wilhelm…https://exercises.lol/video-media/gre_physics/physics-15/physics-15.enzh.mp4?v=1794119438-24142026-10-28yes https://exercises.lol/videos/gre_physics/physics-162026-10-29https://exercises.lol/video-media/gre_physics/physics-16/physics-16.thumb.jpg?v=1793258731Acoustic Doppler echoes and standing-wave boundariesA driver hears the echo from a stationary wall at a shifted pitch, because the outbound and the returning sound each pick up a Doppler factor. This topic…https://exercises.lol/video-media/gre_physics/physics-16/physics-16.enzh.mp4?v=1793258731-23192026-10-28yes https://exercises.lol/videos/gre_physics/physics-172026-11-08https://exercises.lol/video-media/gre_physics/physics-17/physics-17.thumb.jpg?v=1794120516Optical instruments, path differences and refractionIn 1887 Albert Michelson and Edward Morley, in Cleveland, floated a heavy stone table on a pool of mercury so they could turn it smoothly. On it was an…https://exercises.lol/video-media/gre_physics/physics-17/physics-17.enzh.mp4?v=1794120516-23922026-10-28yes https://exercises.lol/videos/gre_physics/physics-182026-10-29https://exercises.lol/video-media/gre_physics/physics-18/physics-18.thumb.jpg?v=1793259095Fourier symmetry and wave superpositionA waveform can contain many harmonics and still have no sine terms at all: reflection symmetry tells you which coefficients vanish before you integrate. This…https://exercises.lol/video-media/gre_physics/physics-18/physics-18.enzh.mp4?v=1793259095-23362026-10-28yes https://exercises.lol/videos/gre_physics/physics-192026-11-08https://exercises.lol/video-media/gre_physics/physics-19/physics-19.thumb.jpg?v=1794120387Gas processes, entropy and reversible cyclesIn 1852 William Thomson, later Lord Kelvin, published a short paper with a surprising idea. A machine could warm a building by pumping heat in from the colder…https://exercises.lol/video-media/gre_physics/physics-19/physics-19.enzh.mp4?v=1794120387-23952026-10-28yes https://exercises.lol/videos/gre_physics/physics-202026-11-08https://exercises.lol/video-media/gre_physics/physics-20/physics-20.thumb.jpg?v=1794119447Speed distributions and statistical ensemblesIn 1920 Otto Stern, in Frankfurt, heated silver in an oven and let a thin beam of silver atoms escape into a vacuum. The beam passed through a slit in a…https://exercises.lol/video-media/gre_physics/physics-20/physics-20.enzh.mp4?v=1794119447-23932026-10-28yes https://exercises.lol/videos/gre_physics/physics-212026-11-08https://exercises.lol/video-media/gre_physics/physics-21/physics-21.thumb.jpg?v=1794119567Counting statistics, uncertainty and dimensional modelsIn 1910 Ernest Rutherford and Hans Geiger counted the tiny flashes made by alpha particles from a radioactive source hitting a zinc sulphide screen. They…https://exercises.lol/video-media/gre_physics/physics-21/physics-21.enzh.mp4?v=1794119567-23912026-10-28yes https://exercises.lol/videos/gre_physics/physics-222026-10-29https://exercises.lol/video-media/gre_physics/physics-22/physics-22.thumb.jpg?v=1793259943Relativistic lifetime, energy and Doppler shiftA fast unstable particle can travel farther in the laboratory than its rest-frame lifetime times its speed would suggest. This topic relates proper lifetime to…https://exercises.lol/video-media/gre_physics/physics-22/physics-22.enzh.mp4?v=1793259943-23612026-10-28yes https://exercises.lol/videos/gre_physics/physics-232026-11-08https://exercises.lol/video-media/gre_physics/physics-23/physics-23.thumb.jpg?v=1794119800Photoelectrons, reduced mass and atomic excitationIn 1914 James Franck and Gustav Hertz sent electrons through mercury vapour and slowly raised the accelerating voltage. The current rose, then dropped sharply…https://exercises.lol/video-media/gre_physics/physics-23/physics-23.enzh.mp4?v=1794119800-23862026-10-28yes https://exercises.lol/videos/gre_physics/physics-242026-11-08https://exercises.lol/video-media/gre_physics/physics-24/physics-24.thumb.jpg?v=1794120051Scattering, degeneracy and Pauli operatorsIn February 1922 Otto Stern and Walther Gerlach, in Frankfurt, sent a beam of silver atoms through a strongly non-uniform magnetic field and collected them on…https://exercises.lol/video-media/gre_physics/physics-24/physics-24.enzh.mp4?v=1794120051-24132026-10-28yes https://exercises.lol/videos/gre_physics/physics-252026-11-08https://exercises.lol/video-media/gre_physics/physics-25/physics-25.thumb.jpg?v=1794120069Nuclear binding, particle families and Hall carriersIn 1879 Edwin Hall, a graduate student at Johns Hopkins University, passed a current along a thin strip of gold leaf placed in a strong magnetic field. A…https://exercises.lol/video-media/gre_physics/physics-25/physics-25.enzh.mp4?v=1794120069-24022026-10-28yes https://exercises.lol/videos/gre_physics/physics-262026-10-29https://exercises.lol/video-media/gre_physics/physics-26/physics-26.thumb.jpg?v=1793260730Constraints, variational equations and cyclic coordinatesA pendulum's string tension changes all through the swing, yet its equation of motion can be found without ever solving for that tension. This topic builds the…https://exercises.lol/video-media/gre_physics/physics-26/physics-26.enzh.mp4?v=1793260730-23752026-10-28yes https://exercises.lol/videos/gre_physics/physics-272026-11-08https://exercises.lol/video-media/gre_physics/physics-27/physics-27.thumb.jpg?v=1794120095Accelerating and rotating reference framesIn 1851 Léon Foucault hung a 28 kg iron ball on a 67 m wire from the dome of the Panthéon in Paris and set it swinging. Over an hour, the line of its swing…https://exercises.lol/video-media/gre_physics/physics-27/physics-27.enzh.mp4?v=1794120095-23902026-10-28yes https://exercises.lol/videos/gre_physics/physics-282026-11-08https://exercises.lol/video-media/gre_physics/physics-28/physics-28.thumb.jpg?v=1794120152Fluid continuity, pressure energy and viscous flowIn 1883 Osborne Reynolds, in Manchester, ran water from a large tank through a long glass tube and fed a thin streak of dye into the entrance. At low speeds…https://exercises.lol/video-media/gre_physics/physics-28/physics-28.enzh.mp4?v=1794120152-23362026-10-28yes https://exercises.lol/videos/gre_physics/physics-292026-10-29https://exercises.lol/video-media/gre_physics/physics-29/physics-29.thumb.jpg?v=1793261289Polarisation, magnetisation and material fieldsSliding a dielectric into a capacitor changes the field one way if the battery has been disconnected and another way if it is still connected. This topic…https://exercises.lol/video-media/gre_physics/physics-29/physics-29.enzh.mp4?v=1793261289-23592026-10-28yes https://exercises.lol/videos/gre_physics/physics-302026-11-08https://exercises.lol/video-media/gre_physics/physics-30/physics-30.thumb.jpg?v=1794120883RC and RL transients, impedance and resonanceIn 1887 Heinrich Hertz, in Karlsruhe, made sparks jump across a small gap in a circuit of wire and metal plates: in effect an inductor and a capacitor…https://exercises.lol/video-media/gre_physics/physics-30/physics-30.enzh.mp4?v=1794120883-24492026-10-28yes https://exercises.lol/videos/gre_physics/physics-312026-11-08https://exercises.lol/video-media/gre_physics/physics-31/physics-31.thumb.jpg?v=1794120801Polarisation, analyser chains and phaseOne evening in 1808, Étienne-Louis Malus looked through a crystal of calcite at the sunset reflected in the windows of the Luxembourg Palace in Paris. Calcite…https://exercises.lol/video-media/gre_physics/physics-31/physics-31.enzh.mp4?v=1794120801-23852026-10-28yes https://exercises.lol/videos/gre_physics/physics-322026-11-08https://exercises.lol/video-media/gre_physics/physics-32/physics-32.thumb.jpg?v=1794120463Diffraction envelopes and missing interference ordersIn 1818 Augustin Fresnel entered a prize competition in Paris with a wave theory of diffraction. One judge, Siméon Poisson, thought he had found an absurd…https://exercises.lol/video-media/gre_physics/physics-32/physics-32.enzh.mp4?v=1794120463-23452026-10-28yes https://exercises.lol/videos/gre_physics/physics-332026-11-08https://exercises.lol/video-media/gre_physics/physics-33/physics-33.thumb.jpg?v=1794120534Signed lens and mirror imagesIn 1668 Isaac Newton built a small telescope only about 15 cm long that magnified about 40 times. Lens telescopes of the time blurred colours, because a lens…https://exercises.lol/video-media/gre_physics/physics-33/physics-33.enzh.mp4?v=1794120534-23692026-10-28yes https://exercises.lol/videos/gre_physics/physics-342026-11-08https://exercises.lol/video-media/gre_physics/physics-34/physics-34.thumb.jpg?v=1794120532Thermal transport, calorimetry and expansionAround 1761 Joseph Black, a professor in Glasgow, put a flask of ice and a flask of ice-cold water side by side in a warm room. The water warmed by several…https://exercises.lol/video-media/gre_physics/physics-34/physics-34.enzh.mp4?v=1794120532-23992026-10-28yes https://exercises.lol/videos/gre_physics/physics-352026-11-08https://exercises.lol/video-media/gre_physics/physics-35/physics-35.thumb.jpg?v=1794120894Partition derivatives, energy fluctuations and heat capacityIn 1902 Josiah Willard Gibbs, at Yale, published Elementary Principles in Statistical Mechanics. He imagined a huge collection of copies of one system, all at…https://exercises.lol/video-media/gre_physics/physics-35/physics-35.enzh.mp4?v=1794120894-23342026-10-28yes https://exercises.lol/videos/gre_physics/physics-362026-11-08https://exercises.lol/video-media/gre_physics/physics-36/physics-36.thumb.jpg?v=1794121064Quantum occupations and limits of equipartitionIn 1875 Heinrich Weber measured the heat capacity of diamond and found it was only about a quarter of the classical value, 3R per mole, that most solids reach…https://exercises.lol/video-media/gre_physics/physics-36/physics-36.enzh.mp4?v=1794121064-24002026-10-28yes https://exercises.lol/videos/gre_physics/physics-372026-11-08https://exercises.lol/video-media/gre_physics/physics-37/physics-37.thumb.jpg?v=1794121265Weak perturbations and degenerate subspacesIn 1913 Johannes Stark put hydrogen atoms in a very strong electric field and found that each Balmer line split into several components. Bohr's model could not…https://exercises.lol/video-media/gre_physics/physics-37/physics-37.enzh.mp4?v=1794121265-23492026-10-28yes https://exercises.lol/videos/gre_physics/physics-382026-11-08https://exercises.lol/video-media/gre_physics/physics-38/physics-38.thumb.jpg?v=1794120539Exchange symmetry, spin pairs and Pauli exclusionIn 1927 Walter Heitler and Fritz London calculated the energy of two hydrogen atoms brought close together. With the electrons' spins opposite (a singlet), the…https://exercises.lol/video-media/gre_physics/physics-38/physics-38.enzh.mp4?v=1794120539-23802026-10-28yes https://exercises.lol/videos/gre_physics/physics-392026-10-29https://exercises.lol/video-media/gre_physics/physics-39/physics-39.thumb.jpg?v=1793263524Finite-well bound states and hydrogenic quantum numbersA bound wavefunction reaches outside a finite well, even though the particle's energy is below the potential there. This topic matches decaying tails to find…https://exercises.lol/video-media/gre_physics/physics-39/physics-39.enzh.mp4?v=1793263524-24602026-10-28yes https://exercises.lol/videos/gre_physics/physics-402026-11-08https://exercises.lol/video-media/gre_physics/physics-40/physics-40.thumb.jpg?v=1794120830Atomic field shifts and spectral differencesIn 1896 Pieter Zeeman, in Leiden, held a sodium flame between the poles of a strong electromagnet and looked at the yellow D lines through a fine diffraction…https://exercises.lol/video-media/gre_physics/physics-40/physics-40.enzh.mp4?v=1794120830-23862026-10-28yes https://exercises.lol/videos/gre_physics/physics-412026-10-29https://exercises.lol/video-media/gre_physics/physics-41/physics-41.thumb.jpg?v=1793263997Thermal spectra and one-electron scalingA spectral peak, a total radiated flux and the energy of one photon are three different things to measure. This topic separates them for thermal radiation…https://exercises.lol/video-media/gre_physics/physics-41/physics-41.enzh.mp4?v=1793263997-24672026-10-28yes https://exercises.lol/videos/gre_physics/physics-422026-11-08https://exercises.lol/video-media/gre_physics/physics-42/physics-42.thumb.jpg?v=1794120882Simultaneity, length measurement and velocity transformationIn June 1905 Albert Einstein began "On the Electrodynamics of Moving Bodies" with what looked like a trivial question: what does it mean to say two events…https://exercises.lol/video-media/gre_physics/physics-42/physics-42.enzh.mp4?v=1794120882-23842026-10-28yes https://exercises.lol/videos/gre_physics/physics-432026-11-08https://exercises.lol/video-media/gre_physics/physics-43/physics-43.thumb.jpg?v=1794123470Measurement loading, amplifier gain and detector responseIn 1928 Hans Geiger and his student Walther Müller, in Kiel, built a gas-filled tube that produced a large electrical pulse for each ionising particle passing…https://exercises.lol/video-media/gre_physics/physics-43/physics-43.enzh.mp4?v=1794123470-23682026-10-28yes https://exercises.lol/videos/gre_physics/physics-442026-10-29https://exercises.lol/video-media/gre_physics/physics-44/physics-44.thumb.jpg?v=1793267247Radiation attenuation, laser gain and cavity modesA photon beam has no definite range, but a heavy charged particle does, and shielding calculations fail if the two are swapped. This topic separates stopping…https://exercises.lol/video-media/gre_physics/physics-44/physics-44.enzh.mp4?v=1793267247-23202026-10-28yes https://exercises.lol/videos/gre_physics/physics-452026-11-08https://exercises.lol/video-media/gre_physics/physics-45/physics-45.thumb.jpg?v=1794121143Bragg diffraction and electron-gas heat capacityIn 1912 Max von Laue's group in Munich sent X-rays through a copper sulfate crystal and found a pattern of spots on a photographic plate. Later that year…https://exercises.lol/video-media/gre_physics/physics-45/physics-45.enzh.mp4?v=1794121143-23922026-10-28yes https://exercises.lol/videos/gre_physics/physics-462026-11-08https://exercises.lol/video-media/gre_physics/physics-46/physics-46.thumb.jpg?v=1794121231Reaction energies, activity and decay balancesJust before Christmas 1938, Otto Hahn and Fritz Strassmann in Berlin found barium among the products of uranium bombarded with neutrons. Barium is about half…https://exercises.lol/video-media/gre_physics/physics-46/physics-46.enzh.mp4?v=1794121231-23862026-10-28yes https://exercises.lol/videos/gre_physics/physics-472026-11-08https://exercises.lol/video-media/gre_physics/physics-47/physics-47.thumb.jpg?v=1794121282Coordinate operators, separated modes and stable updatesIn 1928 Richard Courant, Kurt Friedrichs and Hans Lewy in Göttingen asked when a step-by-step computer-style calculation of a wave actually follows the true…https://exercises.lol/video-media/gre_physics/physics-47/physics-47.enzh.mp4?v=1794121282-23682026-10-28yes https://exercises.lol/videos/gre_psychology/session5-i2026-10-29https://exercises.lol/video-media/gre_psychology/session5-i/session5-i.thumb.jpg?v=1793269431Biological psychologyA biological explanation needs a path from a physical process to the observed behaviour. Receptors change stimulus energy into neural signals; connected brain…https://exercises.lol/video-media/gre_psychology/session5-i/session5-i.enzh.mp4?v=1793269431-22052026-10-28yes https://exercises.lol/videos/gre_psychology/session5-ii2026-11-08https://exercises.lol/video-media/gre_psychology/session5-ii/session5-ii.thumb.jpg?v=1794121705Cognition, language and learningIn the 1880s Hermann Ebbinghaus, in Berlin, memorised hundreds of lists of nonsense syllables such as "DAX" and "BOK", chosen so that meaning could not help.…https://exercises.lol/video-media/gre_psychology/session5-ii/session5-ii.enzh.mp4?v=1794121705-22862026-10-28yes https://exercises.lol/videos/gre_psychology/session5-iii2026-11-08https://exercises.lol/video-media/gre_psychology/session5-iii/session5-iii.thumb.jpg?v=1794122007Social psychologyIn the early 1930s Richard LaPiere drove around the United States with a young Chinese couple, at a time of strong prejudice against Chinese people. They were…https://exercises.lol/video-media/gre_psychology/session5-iii/session5-iii.enzh.mp4?v=1794122007-22832026-10-28yes https://exercises.lol/videos/gre_psychology/session5-iv2026-11-08https://exercises.lol/video-media/gre_psychology/session5-iv/session5-iv.thumb.jpg?v=1794121738Developmental psychologyIn 1956 K. Warner Schaie began testing the mental abilities of adults in Seattle, from their twenties to their seventies. Comparing age groups at one time…https://exercises.lol/video-media/gre_psychology/session5-iv/session5-iv.enzh.mp4?v=1794121738-22902026-10-28yes https://exercises.lol/videos/gre_psychology/session5-v2026-11-08https://exercises.lol/video-media/gre_psychology/session5-v/session5-v.thumb.jpg?v=1794123091Personality, clinical and abnormal psychologyIn 1968 Walter Mischel, at Stanford, reviewed decades of personality research and reached an uncomfortable conclusion. A person's score on a trait test rarely…https://exercises.lol/video-media/gre_psychology/session5-v/session5-v.enzh.mp4?v=1794123091-23092026-10-28yes https://exercises.lol/videos/gre_psychology/session5-vi2026-11-08https://exercises.lol/video-media/gre_psychology/session5-vi/session5-vi.thumb.jpg?v=1794125653Measurement, methods, statistics and historyIn 2015 a team of 270 researchers, the Open Science Collaboration, repeated 100 studies from three leading psychology journals as closely as they could. In the…https://exercises.lol/video-media/gre_psychology/session5-vi/session5-vi.enzh.mp4?v=1794125653-23272026-10-28yes https://exercises.lol/videos/gre_psychology/session5-vii2026-11-08https://exercises.lol/video-media/gre_psychology/session5-vii/session5-vii.thumb.jpg?v=1794123092Historical perspectives and psychometric interpretationIn 1904 the French Ministry of Education asked Alfred Binet to find a way to identify children who needed extra help at school. With Théodore Simon he built a…https://exercises.lol/video-media/gre_psychology/session5-vii/session5-vii.enzh.mp4?v=1794123092-23372026-10-28yes https://exercises.lol/videos/gre_psychology/session5-cl-12026-11-08https://exercises.lol/video-media/gre_psychology/session5-cl-1/session5-cl-1.thumb.jpg?v=1794121472Diagnostic systems and disorder classificationIn the late 1960s the US–UK Diagnostic Project showed the same videotaped patient interviews to psychiatrists in New York and London. The New York…https://exercises.lol/video-media/gre_psychology/session5-cl-1/session5-cl-1.enzh.mp4?v=1794121472-23342026-10-28yes https://exercises.lol/videos/gre_psychology/session5-cl-22026-11-08https://exercises.lol/video-media/gre_psychology/session5-cl-2/session5-cl-2.thumb.jpg?v=1794121898Treatment models and outcome evidenceIn 1952 Hans Eysenck, in London, reviewed reports on psychotherapy and claimed that about two thirds of people with neurotic problems improved within two years…https://exercises.lol/video-media/gre_psychology/session5-cl-2/session5-cl-2.enzh.mp4?v=1794121898-23522026-10-28yes https://exercises.lol/videos/gre_psychology/session5-mm-12026-10-30https://exercises.lol/video-media/gre_psychology/session5-mm-1/session5-mm-1.thumb.jpg?v=1793396998Psychometrics and test constructionChoose the reliability coefficient by the source of variation being studied. A standard error of measurement concerns measurement uncertainty under a model; it…https://exercises.lol/video-media/gre_psychology/session5-mm-1/session5-mm-1.enzh.mp4?v=1793396998-22972026-10-28yes https://exercises.lol/videos/gre_psychology/session5-mm-22026-11-08https://exercises.lol/video-media/gre_psychology/session5-mm-2/session5-mm-2.thumb.jpg?v=1794123080Research designs and statistical interpretationAt a summer tea party in Cambridge in the 1920s, the biologist Muriel Bristol said she could taste whether the milk had been poured into the cup before or…https://exercises.lol/video-media/gre_psychology/session5-mm-2/session5-mm-2.enzh.mp4?v=1794123080-23362026-10-28yes https://exercises.lol/videos/gre_psychology/session5-sp-12026-10-29https://exercises.lol/video-media/gre_psychology/session5-sp-1/session5-sp-1.thumb.jpg?v=1793270786Sensation, perception and psychophysicsA threshold is defined by a detection criterion under specified conditions, often 50% detection for an absolute threshold, rather than a sharp physical…https://exercises.lol/video-media/gre_psychology/session5-sp-1/session5-sp-1.enzh.mp4?v=1793270786-22852026-10-28yes https://exercises.lol/videos/gre_psychology/session5-ne-12026-11-08https://exercises.lol/video-media/gre_psychology/session5-ne-1/session5-ne-1.thumb.jpg?v=1794122284Neurons, synapses and brain systemsOn the night before Easter Sunday in 1921, the pharmacologist Otto Loewi woke from a dream with an experiment in mind, scribbled it on paper, and in the…https://exercises.lol/video-media/gre_psychology/session5-ne-1/session5-ne-1.enzh.mp4?v=1794122284-23702026-10-28yes https://exercises.lol/videos/gre_psychology/session5-dv-12026-10-29https://exercises.lol/video-media/gre_psychology/session5-dv-1/session5-dv-1.thumb.jpg?v=1793268040Developmental theories and milestonesAssimilation uses an existing scheme; accommodation changes the scheme when it does not fit. Conservation tasks examine whether a transformation changes a…https://exercises.lol/video-media/gre_psychology/session5-dv-1/session5-dv-1.enzh.mp4?v=1793268040-22612026-10-28yes https://exercises.lol/videos/gre_psychology/session5-ht-12026-11-08https://exercises.lol/video-media/gre_psychology/session5-ht-1/session5-ht-1.thumb.jpg?v=1794121580Theorists, schools and their claimsIn 1879 Wilhelm Wundt set aside a room at the University of Leipzig for psychological experiments: measuring reaction times and asking trained observers to…https://exercises.lol/video-media/gre_psychology/session5-ht-1/session5-ht-1.enzh.mp4?v=1794121580-23492026-10-28yes https://exercises.lol/videos/gre_psychology/session5-lr-12026-11-08https://exercises.lol/video-media/gre_psychology/session5-lr-1/session5-lr-1.thumb.jpg?v=1794121833Conditioning, reinforcement and observational learningIvan Pavlov won the 1904 Nobel Prize for his work on digestion, not for the discovery he is now famous for. While measuring the saliva of dogs in his St…https://exercises.lol/video-media/gre_psychology/session5-lr-1/session5-lr-1.enzh.mp4?v=1794121833-24022026-10-28yes https://exercises.lol/videos/gre_psychology/session5-me-12026-11-08https://exercises.lol/video-media/gre_psychology/session5-me-1/session5-me-1.thumb.jpg?v=1794123092Memory systems, processes and forgettingIn 1953 the surgeon William Scoville removed parts of both temporal lobes, including most of the hippocampus, from a 27-year-old man with severe epilepsy…https://exercises.lol/video-media/gre_psychology/session5-me-1/session5-me-1.enzh.mp4?v=1794123092-23702026-10-28yes https://exercises.lol/videos/gre_psychology/session5-lg-12026-11-08https://exercises.lol/video-media/gre_psychology/session5-lg-1/session5-lg-1.thumb.jpg?v=1794124273Language structure, perception and acquisitionIn 1996 Jenny Saffran, Richard Aslin and Elissa Newport played eight-month-old babies two minutes of a made-up language: a smooth stream of syllables such as…https://exercises.lol/video-media/gre_psychology/session5-lg-1/session5-lg-1.enzh.mp4?v=1794124273-23552026-10-28yes https://exercises.lol/videos/gre_psychology/session5-th-12026-11-08https://exercises.lol/video-media/gre_psychology/session5-th-1/session5-th-1.thumb.jpg?v=1794122304Thinking, problem solving and intelligenceIn 1983 Amos Tversky and Daniel Kahneman described Linda: 31, single, outspoken and very bright, a philosophy graduate who cared about discrimination and…https://exercises.lol/video-media/gre_psychology/session5-th-1/session5-th-1.enzh.mp4?v=1794122304-23482026-10-28yes https://exercises.lol/videos/gre_psychology/session5-so-12026-11-08https://exercises.lol/video-media/gre_psychology/session5-so-1/session5-so-1.thumb.jpg?v=1794122309Social cognition, attribution and social influenceIn 1951 Solomon Asch, at Swarthmore College, showed students a line and asked which of three comparison lines matched it. The answer was obvious: alone, people…https://exercises.lol/video-media/gre_psychology/session5-so-1/session5-so-1.enzh.mp4?v=1794122309-23792026-10-28yes https://exercises.lol/videos/gre_psychology/session5-so-22026-11-08https://exercises.lol/video-media/gre_psychology/session5-so-2/session5-so-2.thumb.jpg?v=1794123155Groups, relationships and intergroup processesIn 1968 John Darley and Bibb Latané asked New York students to talk about college life over an intercom, one at a time. Suddenly one voice, a recording, began…https://exercises.lol/video-media/gre_psychology/session5-so-2/session5-so-2.enzh.mp4?v=1794123155-23522026-10-28yes https://exercises.lol/videos/gre_psychology/session5-at-12026-11-08https://exercises.lol/video-media/gre_psychology/session5-at-1/session5-at-1.thumb.jpg?v=1794121902Attention limits and non-associative learningIn 1953 Colin Cherry, an engineer in London, played two different spoken messages through headphones, one to each ear, and asked listeners to repeat one…https://exercises.lol/video-media/gre_psychology/session5-at-1/session5-at-1.enzh.mp4?v=1794121902-23412026-10-28yes https://exercises.lol/videos/gre_psychology/session5-ex-12026-10-29https://exercises.lol/video-media/gre_psychology/session5-ex-1/session5-ex-1.thumb.jpg?v=1793268375Evolutionary and comparative perspectivesHamilton's inequality is a model of selection under stated costs, benefits and relatedness, not an instruction about human duty. Inclusive fitness concerns…https://exercises.lol/video-media/gre_psychology/session5-ex-1/session5-ex-1.enzh.mp4?v=1793268375-22752026-10-28yes https://exercises.lol/videos/gre_psychology/session5-me-22026-10-29https://exercises.lol/video-media/gre_psychology/session5-me-2/session5-me-2.thumb.jpg?v=1793270095Encoding depth and retrieval routesSemantic elaboration often supports later meaning-based recall because it creates useful relationships and retrieval routes. Maintenance repetition can keep…https://exercises.lol/video-media/gre_psychology/session5-me-2/session5-me-2.enzh.mp4?v=1793270095-22372026-10-28yes https://exercises.lol/videos/gre_psychology/session5-hb-12026-10-29https://exercises.lol/video-media/gre_psychology/session5-hb-1/session5-hb-1.thumb.jpg?v=1793268377Hormones, stress and behavioural regulationThe HPA sequence connects hypothalamic CRH, pituitary ACTH and adrenal-cortex cortisol. Cortisol participates in feedback that can inhibit upstream release.…https://exercises.lol/video-media/gre_psychology/session5-hb-1/session5-hb-1.enzh.mp4?v=1793268377-22502026-10-28yes https://exercises.lol/videos/gre_psychology/session5-ep-12026-11-08https://exercises.lol/video-media/gre_psychology/session5-ep-1/session5-ep-1.thumb.jpg?v=1794122054Epidemiology and clinical evidenceIn 1950 Richard Doll and Austin Bradford Hill compared 709 lung cancer patients in London hospitals with 709 patients of the same sex and age who had other…https://exercises.lol/video-media/gre_psychology/session5-ep-1/session5-ep-1.enzh.mp4?v=1794122054-23662026-10-28yes https://exercises.lol/videos/hsk0/first-sounds2026-10-30https://exercises.lol/video-media/hsk0/first-sounds/first-sounds.thumb.jpg?v=1793372415HSK 0 · Find your first soundsBefore words come sounds. Every Chinese syllable is an initial plus a final, said in one beat. Learn the families English does not have: the puff pairs b, p…https://exercises.lol/video-media/hsk0/first-sounds/first-sounds.enzh.mp4?v=1793372415-21632026-10-30yes https://exercises.lol/videos/hsk0/four-tones2026-10-30https://exercises.lol/video-media/hsk0/four-tones/four-tones.thumb.jpg?v=1793372577HSK 0 · Hear and practise the four tonesChinese gives every syllable a tune, and the tune is part of the word. 妈, high and flat, is mother. 麻, rising, is hemp. 马, dipping low and lifting, is horse.…https://exercises.lol/video-media/hsk0/four-tones/four-tones.enzh.mp4?v=1793372577-21732026-10-30yes https://exercises.lol/videos/hsk0/neutral-tone-and-sandhi2026-10-30https://exercises.lol/video-media/hsk0/neutral-tone-and-sandhi/neutral-tone-and-sandhi.thumb.jpg?v=1793372420HSK 0 · Light syllables and common tone changesSome syllables work less than others. The neutral tone is a quick, light tap with no tune of its own, the second beat of 妈妈. And three things bend when they…https://exercises.lol/video-media/hsk0/neutral-tone-and-sandhi/neutral-tone-and-sandhi.enzh.mp4?v=1793372420-21902026-10-30yes https://exercises.lol/videos/hsk0/pinyin-not-english2026-10-30https://exercises.lol/video-media/hsk0/pinyin-not-english/pinyin-not-english.thumb.jpg?v=1793372580HSK 0 · Read pinyin without English guessesPinyin uses English letters with Chinese meanings, and six of them mislead beginners every time: q, which is a light ch; x, the smiling hiss; c, which says ts…https://exercises.lol/video-media/hsk0/pinyin-not-english/pinyin-not-english.enzh.mp4?v=1793372580-21892026-10-30yes https://exercises.lol/videos/hsk0/characters-components2026-10-30https://exercises.lol/video-media/hsk0/characters-components/characters-components.thumb.jpg?v=1793372580HSK 0 · Recognise characters and useful componentsCharacters are pictures that grew up. Some still show their photos: the sun in a window, the crescent moon, the three peaks of a mountain. Others are built…https://exercises.lol/video-media/hsk0/characters-components/characters-components.enzh.mp4?v=1793372580-21802026-10-30yes https://exercises.lol/videos/hsk0/typing-and-routine2026-10-30https://exercises.lol/video-media/hsk0/typing-and-routine/typing-and-routine.thumb.jpg?v=1793372575HSK 0 · Type a sentence and choose a study routinePinyin turns any keyboard into a Chinese keyboard: type the sound, pick the character from a list ordered by frequency. And a course is a habit, not a sprint.…https://exercises.lol/video-media/hsk0/typing-and-routine/typing-and-routine.enzh.mp4?v=1793372575-21662026-10-30yes https://exercises.lol/videos/hsk1/introductions-and-polite-words2026-11-08https://exercises.lol/video-media/hsk1/introductions-and-polite-words/introductions-and-polite-words.thumb.jpg?v=1794105232HSK 1 · Introductions, Identity and Polite ExchangesYour first Chinese conversation. Greet someone, give your name, and ask a yes-or-no question with 吗. Then add three small words: 的 for whose, 也 and 都 for also…https://exercises.lol/video-media/hsk1/introductions-and-polite-words/introductions-and-polite-words.enzh.mp4?v=1794105232-22712026-10-08yes https://exercises.lol/videos/hsk1/dates-time-and-numbers2026-10-30https://exercises.lol/video-media/hsk1/dates-time-and-numbers/dates-time-and-numbers.thumb.jpg?v=1793319735HSK 1 · Dates, Time and Event InformationNumbers, dates, and two magic questions. Numbers stack like blocks, dates run big-to-small, and two question words unlock every timetable. 几点 for clock time…https://exercises.lol/video-media/hsk1/dates-time-and-numbers/dates-time-and-numbers.enzh.mp4?v=1793319735-21532026-10-08yes https://exercises.lol/videos/hsk1/objects-quantities-and-buying2026-10-30https://exercises.lol/video-media/hsk1/objects-quantities-and-buying/objects-quantities-and-buying.thumb.jpg?v=1793319944HSK 1 · Objects, Quantities and BuyingYour first shopping trip. Count with measure words, ask the price, say what you want : three moves and the shop is yours. 两 counts objects; 二 stays in dates. 的…https://exercises.lol/video-media/hsk1/objects-quantities-and-buying/objects-quantities-and-buying.enzh.mp4?v=1793319944-21522026-10-08yes https://exercises.lol/videos/hsk1/weather-places-and-location2026-10-30https://exercises.lol/video-media/hsk1/weather-places-and-location/weather-places-and-location.thumb.jpg?v=1793319938HSK 1 · Weather, Places and LocationTwo patterns for weather and places. An adjective sentence needs no 是, because the adjective works as the verb: 今天很热。 And 在 pins things to places. Remember the…https://exercises.lol/video-media/hsk1/weather-places-and-location/weather-places-and-location.enzh.mp4?v=1793319938-21652026-10-08yes https://exercises.lol/videos/hsk1/meals-and-foods2026-10-30https://exercises.lol/video-media/hsk1/meals-and-foods/meals-and-foods.thumb.jpg?v=1793319643HSK 1 · Meals and Traditional FoodsLunch, with grammar. 吃 eats, 喝 drinks, 想 would like : and two markers, 在 and 了, tell you when the action happens. One meal, three tenses of intention. 了 is not…https://exercises.lol/video-media/hsk1/meals-and-foods/meals-and-foods.enzh.mp4?v=1793319643-21482026-10-08yes https://exercises.lol/videos/hsk1/travel-and-directions2026-11-08https://exercises.lol/video-media/hsk1/travel-and-directions/travel-and-directions.thumb.jpg?v=1794108548HSK 1 · Travel, Destinations and Simple DirectionsOne sentence, four facts. 去 goes, 坐 rides, and every ticket answers three questions: destination, mode, time. 我明天八点坐火车去上海 : date, hour, mode, destination. 在 is…https://exercises.lol/video-media/hsk1/travel-and-directions/travel-and-directions.enzh.mp4?v=1794108548-21492026-10-08yes https://exercises.lol/videos/hsk1/wellbeing-and-leisure2026-10-30https://exercises.lol/video-media/hsk1/wellbeing-and-leisure/wellbeing-and-leisure.thumb.jpg?v=1793320117HSK 1 · Needs, Wellbeing and LeisureFeeling unwell, wanting fun. 我不舒服 says you feel unwell; 你想做什么？ asks about free time : and Chinese has two "can" words. 会 means learned skill; 能 means today's…https://exercises.lol/video-media/hsk1/wellbeing-and-leisure/wellbeing-and-leisure.enzh.mp4?v=1793320117-21472026-10-08yes https://exercises.lol/videos/hsk1/school-study-and-routines2026-11-08https://exercises.lol/video-media/hsk1/school-study-and-routines/school-study-and-routines.thumb.jpg?v=1794108526HSK 1 · School, Study and Work RoutinesThis topic covers three things. A routine sentence puts the person first, then the time, then the verb and the object. 有 says what you have, and 没有 says what…https://exercises.lol/video-media/hsk1/school-study-and-routines/school-study-and-routines.enzh.mp4?v=1794108526-21582026-10-08yes https://exercises.lol/videos/hsk1/listening-and-reading-habits2026-10-30https://exercises.lol/video-media/hsk1/listening-and-reading-habits/listening-and-reading-habits.thumb.jpg?v=1793320206HSK 1 · Listening and Reading HabitsAt level one, the questions reward three habits. Hear the whole phrase, read the whole sentence, and match the fact to the question word. A familiar noun on…https://exercises.lol/video-media/hsk1/listening-and-reading-habits/listening-and-reading-habits.enzh.mp4?v=1793320206-21462026-10-08yes https://exercises.lol/videos/hsk2/descriptions-requests-address2026-10-30https://exercises.lol/video-media/hsk2/descriptions-requests-address/descriptions-requests-address.thumb.jpg?v=1793335863HSK 2 · Personal Descriptions, Requests and Forms of AddressPolite Chinese in four moves. Respectful titles, adjective descriptions, permission and requests : and the 为什么 or 因为 pair. Titles follow role, not English…https://exercises.lol/video-media/hsk2/descriptions-requests-address/descriptions-requests-address.enzh.mp4?v=1793335863-21302026-10-08yes https://exercises.lol/videos/hsk2/shopping-comparisons2026-10-30https://exercises.lol/video-media/hsk2/shopping-comparisons/shopping-comparisons.thumb.jpg?v=1793320464HSK 2 · Events, Objects and Shopping ComparisonsThis topic does three jobs. 比 compares two things: 这本书比那本书贵。 本 and 件 count books and clothes. And 已经 with 了 says something is already done. Remember: no 很…https://exercises.lol/video-media/hsk2/shopping-comparisons/shopping-comparisons.enzh.mp4?v=1793320464-21622026-10-08yes https://exercises.lol/videos/hsk2/places-and-directions2026-10-30https://exercises.lol/video-media/hsk2/places-and-directions/places-and-directions.thumb.jpg?v=1793335278HSK 2 · Weather, Describing Places and DirectionsGood directions are ones a listener could draw. 从 and 到 frame the route, 往 marks each turn, and 先 and 再 put the steps in order. Always confirm the destination…https://exercises.lol/video-media/hsk2/places-and-directions/places-and-directions.enzh.mp4?v=1793335278-21472026-10-08yes https://exercises.lol/videos/hsk2/experience-and-results2026-10-30https://exercises.lol/video-media/hsk2/experience-and-results/experience-and-results.thumb.jpg?v=1793335202HSK 2 · Meals, Leisure, Experience and AdviceExperience, outcome, manner. 过 says have-ever; result complements say did-it-succeed; 得 says how-well. Three verbs, three different claims. An activity and its…https://exercises.lol/video-media/hsk2/experience-and-results/experience-and-results.enzh.mp4?v=1793335202-21662026-10-08yes https://exercises.lol/videos/hsk2/family-and-routines2026-10-30https://exercises.lol/video-media/hsk2/family-and-routines/family-and-routines.thumb.jpg?v=1793319944HSK 2 · Family, Learning History, School and WorkA family roster says who does what, and when. Keep how long something lasts apart from the date. 经常 means often, and 有时候 means sometimes. 正在 marks something…https://exercises.lol/video-media/hsk2/family-and-routines/family-and-routines.enzh.mp4?v=1793319944-21432026-10-08yes https://exercises.lol/videos/hsk2/festivals-reasons-contrasts2026-10-30https://exercises.lol/video-media/hsk2/festivals-reasons-contrasts/festivals-reasons-contrasts.thumb.jpg?v=1793320187HSK 2 · Festivals, Reasons, Contrasts and ChoicesThis topic is the grammar of explaining yourself. There are two words for or: 还是 asks, and 或者 states. 因为 and 所以 give a reason and its result. 虽然 and 但是 admit a…https://exercises.lol/video-media/hsk2/festivals-reasons-contrasts/festivals-reasons-contrasts.enzh.mp4?v=1793320187-21362026-10-08yes https://exercises.lol/videos/hsk2/writing-characters2026-10-30https://exercises.lol/video-media/hsk2/writing-characters/writing-characters.thumb.jpg?v=1793320474HSK 2 · Build Characters and Use Pinyin in a SentenceThe writing task is real. Ten writing items join twenty-five listening and twenty-five reading : ten minutes, real handwriting. First five: complete a…https://exercises.lol/video-media/hsk2/writing-characters/writing-characters.enzh.mp4?v=1793320474-21622026-10-08yes https://exercises.lol/videos/hsk3/describing-and-degree2026-11-08https://exercises.lol/video-media/hsk3/describing-and-degree/describing-and-degree.thumb.jpg?v=1794127494HSK 3 Grammar 1: Describing & DegreeHow Chinese describes things. First, setting the degree: 极了, 多……啊, 比较 and 这么. Then describing nouns and actions with 的, 地 and doubled adjectives. Finally, two…https://exercises.lol/video-media/hsk3/describing-and-degree/describing-and-degree.enzh.mp4?v=1794127494-23012026-10-08yes https://exercises.lol/videos/hsk3/adverbs-time-focus-frequency2026-10-30https://exercises.lol/video-media/hsk3/adverbs-time-focus-frequency/adverbs-time-focus-frequency.thumb.jpg?v=1793353027HSK 3 Grammar 2: Adverbs — Time, Focus & FrequencyThe time-and-frequency toolbox. 又 for repeats, 一直 or 总是 for two always-s, 终于 for finally, 只 for only, 才 for late, and the after-then trio. Position and pairing…https://exercises.lol/video-media/hsk3/adverbs-time-focus-frequency/adverbs-time-focus-frequency.enzh.mp4?v=1793353027-22592026-10-08yes https://exercises.lol/videos/hsk3/verbs-ability-and-complements2026-10-30https://exercises.lol/video-media/hsk3/verbs-ability-and-complements/verbs-ability-and-complements.thumb.jpg?v=1793321866HSK 3 Grammar 3: Verbs, Ability & ComplementsThis topic is about what verbs report. 着 holds a state. The 了 at the end of a sentence announces a change: it is now true. Result complements report the…https://exercises.lol/video-media/hsk3/verbs-ability-and-complements/verbs-ability-and-complements.enzh.mp4?v=1793321866-22552026-10-08yes https://exercises.lol/videos/hsk3/comparisons2026-10-30https://exercises.lol/video-media/hsk3/comparisons/comparisons.thumb.jpg?v=1793321517HSK 3 Grammar 4: ComparisonsFive comparison tools. 比 means more than. 没有 means not as much as. 跟 with 比 sets a yardstick first. 更 or 还 means even more. And 多了 marks a big gap. One word…https://exercises.lol/video-media/hsk3/comparisons/comparisons.enzh.mp4?v=1793321517-22152026-10-08yes https://exercises.lol/videos/hsk3/particles-nouns-numbers2026-10-30https://exercises.lol/video-media/hsk3/particles-nouns-numbers/particles-nouns-numbers.thumb.jpg?v=1793320853HSK 3 Grammar 5: Particles, Nouns & NumbersHalves, huges numbers, and vague some. 半 mirrors English word order; 万 groups digits in fours; a falling-tone question word means some. The rules are few; the…https://exercises.lol/video-media/hsk3/particles-nouns-numbers/particles-nouns-numbers.enzh.mp4?v=1793320853-22202026-10-08yes https://exercises.lol/videos/hsk3/ba-and-bei-patterns2026-10-30https://exercises.lol/video-media/hsk3/ba-and-bei-patterns/ba-and-bei-patterns.thumb.jpg?v=1793321166HSK 3 Grammar 6: Sentence Patterns (把 & 被)The two famous constructions, demystified. 把 means take it and do something to it; 被 means got done to. Both grab the object and forbid the bare verb. The hand…https://exercises.lol/video-media/hsk3/ba-and-bei-patterns/ba-and-bei-patterns.enzh.mp4?v=1793321166-21992026-10-08yes https://exercises.lol/videos/hsk3/conjunctions-and-conditions2026-10-30https://exercises.lol/video-media/hsk3/conjunctions-and-conditions/conjunctions-and-conditions.thumb.jpg?v=1793320854HSK 3 Grammar 7: Conjunctions & ConditionsTelling, asking, conditioning. 或者 tells, 还是 asks; 只要 needs any door, 只有 has one door; 为了 aims forward, 因为 looks back. The most-tested trap is the or-swap. Each…https://exercises.lol/video-media/hsk3/conjunctions-and-conditions/conjunctions-and-conditions.enzh.mp4?v=1793320854-22682026-10-08yes https://exercises.lol/videos/hsk3/say-aloud-stories2026-10-29https://exercises.lol/video-media/hsk3/say-aloud-stories/say-aloud-stories.thumb.jpg?v=1793274291HSK 3 Say it aloud 8: stories, comparisons and reasonsThis is the speaking floor for everything the grammar built. Tell a short story in time order on the rail xian, ranhou, zuihou. Compare with bi, which says…https://exercises.lol/video-media/hsk3/say-aloud-stories/say-aloud-stories.enzh.mp4?v=1793274291-21732026-10-28yes https://exercises.lol/videos/hsk4/adjectives-whole-and-extreme2026-10-30https://exercises.lol/video-media/hsk4/adjectives-whole-and-extreme/adjectives-whole-and-extreme.thumb.jpg?v=1793323816HSK 4 Grammar 01: AdjectivesTwo patterns carry a lot of HSK 4. 全 before a noun sweeps up the whole thing at once, and an adjective plus 死了 cranks a feeling to its limit. Both are tested…https://exercises.lol/video-media/hsk4/adjectives-whole-and-extreme/adjectives-whole-and-extreme.enzh.mp4?v=1793323816-22242026-10-08yes https://exercises.lol/videos/hsk4/adverbs-five-jobs2026-10-30https://exercises.lol/video-media/hsk4/adverbs-five-jobs/adverbs-five-jobs.thumb.jpg?v=1793333980HSK 4 Grammar 02: AdverbsFive jobs in one lesson. HSK 4 adverbs measure, judge, intensify, press a question, and advise : the exam tests position and pairing, not vocabulary. Whether 都…https://exercises.lol/video-media/hsk4/adverbs-five-jobs/adverbs-five-jobs.enzh.mp4?v=1793333980-22662026-10-08yes https://exercises.lol/videos/hsk4/adverbs-with-adjectives-ting2026-10-30https://exercises.lol/video-media/hsk4/adverbs-with-adjectives-ting/adverbs-with-adjectives-ting.thumb.jpg?v=1793322101HSK 4 Grammar 03: Adverbs with AdjectivesOne pattern owns this topic: 挺, an adjective, then 的. It is the laid-back quite, or pretty, softer than 很 and far short of 非常, and the exam tests the 的 at the…https://exercises.lol/video-media/hsk4/adverbs-with-adjectives-ting/adverbs-with-adjectives-ting.enzh.mp4?v=1793322101-21592026-10-08yes https://exercises.lol/videos/hsk4/auxiliary-words-list-endings2026-10-30https://exercises.lol/video-media/hsk4/auxiliary-words-list-endings/auxiliary-words-list-endings.thumb.jpg?v=1793323757HSK 4 Grammar 04: Auxiliary WordsTwo ways to wave at the rest of a list. 什么的 rounds off a list with a casual wave; 等 or 等等 closes it formally : and Chinese puts no comma before 等. Choosing…https://exercises.lol/video-media/hsk4/auxiliary-words-list-endings/auxiliary-words-list-endings.enzh.mp4?v=1793323757-21662026-10-08yes https://exercises.lol/videos/hsk4/conjunctions-joining-ideas2026-10-30https://exercises.lol/video-media/hsk4/conjunctions-joining-ideas/conjunctions-joining-ideas.thumb.jpg?v=1793322272HSK 4 Grammar 05: ConjunctionsConjunctions join two ideas, and HSK 4 tests whether the join matches the relationship. This topic covers the but family, the and-so chain, the another-thing…https://exercises.lol/video-media/hsk4/conjunctions-joining-ideas/conjunctions-joining-ideas.enzh.mp4?v=1793322272-23472026-10-08yes https://exercises.lol/videos/hsk4/nouns-qizhong2026-10-30https://exercises.lol/video-media/hsk4/nouns-qizhong/nouns-qizhong.thumb.jpg?v=1793321699HSK 4 Grammar 06: NounsOne word owns this topic. 其中 is the Chinese "of which or of them" : and it always looks backward to a group already on the table. It reaches into a set you…https://exercises.lol/video-media/hsk4/nouns-qizhong/nouns-qizhong.enzh.mp4?v=1793321699-21312026-10-08yes https://exercises.lol/videos/hsk4/numbers-fractions-and-percents2026-10-30https://exercises.lol/video-media/hsk4/numbers-fractions-and-percents/numbers-fractions-and-percents.thumb.jpg?v=1793322057HSK 4 Grammar 07: NumbersChinese builds a fraction from the bottom up: the denominator, then 分之, then the numerator. A percentage is just a fraction out of a hundred. The order is the…https://exercises.lol/video-media/hsk4/numbers-fractions-and-percents/numbers-fractions-and-percents.enzh.mp4?v=1793322057-21342026-10-08yes https://exercises.lol/videos/hsk4/particles-ma-ba-de2026-10-30https://exercises.lol/video-media/hsk4/particles-ma-ba-de/particles-ma-ba-de.thumb.jpg?v=1793322348HSK 4 Grammar 08: ParticlesThree particles, three jobs. 吗 can wrap a question that already holds a question word; doubled 吧 builds a dilemma; final 的 seals conviction. Each particle…https://exercises.lol/video-media/hsk4/particles-ma-ba-de/particles-ma-ba-de.enzh.mp4?v=1793322348-22032026-10-08yes https://exercises.lol/videos/hsk4/prepositions-suizhe-and-brackets2026-10-30https://exercises.lol/video-media/hsk4/prepositions-suizhe-and-brackets/prepositions-suizhe-and-brackets.thumb.jpg?v=1793322323HSK 4 Grammar 09: PrepositionsTwo preposition jobs, both formal in flavour. 随着 ties one change to another that moves in step with it. And 在 with 上 or 下 make abstract brackets: a field, or a…https://exercises.lol/video-media/hsk4/prepositions-suizhe-and-brackets/prepositions-suizhe-and-brackets.enzh.mp4?v=1793322323-21642026-10-08yes https://exercises.lol/videos/hsk4/bing-emphatic-negation2026-10-30https://exercises.lol/video-media/hsk4/bing-emphatic-negation/bing-emphatic-negation.thumb.jpg?v=1793322539HSK 4 Grammar 10: Sentence Patterns — Existence & Emphasis并 before 不 or 没 means actually not, despite what you assume. It is the go-to for correcting a wrong impression: firm, a little defensive. And it only ever…https://exercises.lol/video-media/hsk4/bing-emphatic-negation/bing-emphatic-negation.enzh.mp4?v=1793322539-21322026-10-08yes https://exercises.lol/videos/hsk4/yi-wei-take-as2026-10-30https://exercises.lol/video-media/hsk4/yi-wei-take-as/yi-wei-take-as.thumb.jpg?v=1793322562HSK 4 Grammar 11: Sentence Patterns — ComparisonThe frame: take A as B. 以 A 为 B means "take or regard A as B" : your basis, standard or focus, in an elegant, formal frame. Semi-classical, written register.…https://exercises.lol/video-media/hsk4/yi-wei-take-as/yi-wei-take-as.enzh.mp4?v=1793322562-21522026-10-08yes https://exercises.lol/videos/hsk4/verbs-causatives-and-hedges2026-10-30https://exercises.lol/video-media/hsk4/verbs-causatives-and-hedges/verbs-causatives-and-hedges.thumb.jpg?v=1793322966HSK 4 Grammar 12: VerbsEight verb patterns in one lesson. Four causatives, an "it depends", a hedge, an essay verb, a wrong-belief verb, a two-hatted 通过, 来自, and the dummy 来. Each…https://exercises.lol/video-media/hsk4/verbs-causatives-and-hedges/verbs-causatives-and-hedges.enzh.mp4?v=1793322966-22882026-10-08yes https://exercises.lol/videos/hsk4/auxiliary-verbs-buyong-dei2026-11-08https://exercises.lol/video-media/hsk4/auxiliary-verbs-buyong-dei/auxiliary-verbs-buyong-dei.thumb.jpg?v=1794127043HSK 4 Grammar 13: Auxiliary VerbsTwo words move obligations around. 不用 lifts one: no need to. 得 imposes one: have to. Both traps are about pairing: the negative of 要 meaning must, and of 得, is…https://exercises.lol/video-media/hsk4/auxiliary-verbs-buyong-dei/auxiliary-verbs-buyong-dei.enzh.mp4?v=1794127043-21702026-10-08yes https://exercises.lol/videos/hsk4/verb-phrases-joins-and-traps2026-10-30https://exercises.lol/video-media/hsk4/verb-phrases-joins-and-traps/verb-phrases-joins-and-traps.thumb.jpg?v=1793322084HSK 4 Grammar 14: Verb PhrasesEleven patterns, three big traps. Join actions with 并, advise with 少 or 多, assign with 由, blame with 害得 : and mind the two nevers and the separable words. The…https://exercises.lol/video-media/hsk4/verb-phrases-joins-and-traps/verb-phrases-joins-and-traps.enzh.mp4?v=1793322084-22822026-10-08yes https://exercises.lol/videos/hsk4/but-statements-jinguan-dao-que2026-10-30https://exercises.lol/video-media/hsk4/but-statements-jinguan-dao-que/but-statements-jinguan-dao-que.thumb.jpg?v=1793322858HSK 4 Grammar 15: "But" StatementsThree flavours of "but". 尽管 concedes then overrides; 倒 flags the pleasant surprise; 却 marks the disappointing twist from inside the sentence. Choosing 倒 or 却…https://exercises.lol/video-media/hsk4/but-statements-jinguan-dao-que/but-statements-jinguan-dao-que.enzh.mp4?v=1793322858-22102026-10-08yes https://exercises.lol/videos/hsk4/even-if-jishi-ye2026-10-30https://exercises.lol/video-media/hsk4/even-if-jishi-ye/even-if-jishi-ye.thumb.jpg?v=1793323162HSK 4 Grammar 16: "Even if" statements即使 and 也 grant a supposition and say it changes nothing: even if A, still B. The exam tests the 也, and the split between 即使 and 虽然.https://exercises.lol/video-media/hsk4/even-if-jishi-ye/even-if-jishi-ye.enzh.mp4?v=1793323162-21262026-10-08yes https://exercises.lol/videos/hsk4/if-yaoshi-jiu2026-10-30https://exercises.lol/video-media/hsk4/if-yaoshi-jiu/if-yaoshi-jiu.thumb.jpg?v=1793321224HSK 4 Grammar 17: "If" statements要是 and 就 are the everyday spoken if and then, the chatty twin of 如果. The condition leads, and 就 stamps the consequence. The exam checks the 就.https://exercises.lol/video-media/hsk4/if-yaoshi-jiu/if-yaoshi-jiu.enzh.mp4?v=1793321224-21462026-10-08yes https://exercises.lol/videos/hsk4/no-matter-buguan-wulun2026-10-30https://exercises.lol/video-media/hsk4/no-matter-buguan-wulun/no-matter-buguan-wulun.thumb.jpg?v=1793322834HSK 4 Grammar 18: "No matter" statementsWhatever the case, the result holds. 不管 and 无论 say the outcome holds whatever the case : and both demand an open variable in the first clause. Spoken takes 不管…https://exercises.lol/video-media/hsk4/no-matter-buguan-wulun/no-matter-buguan-wulun.enzh.mp4?v=1793322834-21812026-10-08yes https://exercises.lol/videos/hsk4/cause-and-effect-youyu-jiran-yinci2026-10-30https://exercises.lol/video-media/hsk4/cause-and-effect-youyu-jiran-yinci/cause-and-effect-youyu-jiran-yinci.thumb.jpg?v=1793323675HSK 4 Grammar 19: Cause & effect statementsThree words, three jobs. 由于 heads a formal cause; 既然 reasons forward from an accepted fact; 因此 rolls out the consequence. The tested choices are pairing and…https://exercises.lol/video-media/hsk4/cause-and-effect-youyu-jiran-yinci/cause-and-effect-youyu-jiran-yinci.enzh.mp4?v=1793323675-21772026-10-08yes https://exercises.lol/videos/hsk4/complements-qilai-direction-potential2026-10-30https://exercises.lol/video-media/hsk4/complements-qilai-direction-potential/complements-qilai-direction-potential.thumb.jpg?v=1793323470HSK 4 Grammar 20: ComplementsFour complement families. 起来 in three jobs, directional 来 or 去, the sense-verb frame, and potential 得 or 不 : each with one lock-the-door rule. The place slot…https://exercises.lol/video-media/hsk4/complements-qilai-direction-potential/complements-qilai-direction-potential.enzh.mp4?v=1793323470-21862026-10-08yes https://exercises.lol/videos/hsk4/conditionals-zhiyao-zhiyou-chufei2026-10-30https://exercises.lol/video-media/hsk4/conditionals-zhiyao-zhiyou-chufei/conditionals-zhiyao-zhiyou-chufei.thumb.jpg?v=1793323500HSK 4 Grammar 21: Conditional statementsEnough versus the only way. 只要 says one thing is enough; 只有 or 除非 name the one thing that must happen : and the partner word carries the difference. 只要 reaches…https://exercises.lol/video-media/hsk4/conditionals-zhiyao-zhiyou-chufei/conditionals-zhiyao-zhiyou-chufei.enzh.mp4?v=1793323500-21422026-10-08yes https://exercises.lol/videos/hsk4/noun-phrases-suoyou-zhiyi-lingwai2026-10-30https://exercises.lol/video-media/hsk4/noun-phrases-suoyou-zhiyi-lingwai/noun-phrases-suoyou-zhiyi-lingwai.thumb.jpg?v=1793323747HSK 4 Grammar 22: Noun phrasesThree noun tools, three locks. 所有 counts the whole crowd in; 之一 points at one trophy; 另外 hands you the other one. Where 不 sits, where 之一 ends, and the missing…https://exercises.lol/video-media/hsk4/noun-phrases-suoyou-zhiyi-lingwai/noun-phrases-suoyou-zhiyi-lingwai.enzh.mp4?v=1793323747-21632026-10-08yes https://exercises.lol/videos/hsk4/quantity-and-scope-patterns2026-10-30https://exercises.lol/video-media/hsk4/quantity-and-scope-patterns/quantity-and-scope-patterns.thumb.jpg?v=1793335745HSK 4 Grammar 23: Quantity & ScopeFive tools, one golden thread. The repeated verb, the goal-first order, no 的 after 任何, matching halves, and the position word after the place. Each frame dies…https://exercises.lol/video-media/hsk4/quantity-and-scope-patterns/quantity-and-scope-patterns.enzh.mp4?v=1793335745-22072026-10-08yes https://exercises.lol/videos/hsk4/basic-sentence-patterns2026-10-30https://exercises.lol/video-media/hsk4/basic-sentence-patterns/basic-sentence-patterns.thumb.jpg?v=1793321408HSK 4 Grammar 24: Basic Sentence PatternsThe partner-word lesson. Six everyday frames : and most of them die without a partner word: the 都, the 也, the 来. Drop the partner and the frame goes quiet.…https://exercises.lol/video-media/hsk4/basic-sentence-patterns/basic-sentence-patterns.enzh.mp4?v=1793321408-21882026-10-08yes https://exercises.lol/videos/hsk4/complex-sentence-patterns2026-10-30https://exercises.lol/video-media/hsk4/complex-sentence-patterns/complex-sentence-patterns.thumb.jpg?v=1793322802HSK 4 Grammar 25: Complex Sentence PatternsThree grown-up moves. Concede then pull back; bind two events tight; weigh two sides : moves you already make in English. Each has one rule that keeps it…https://exercises.lol/video-media/hsk4/complex-sentence-patterns/complex-sentence-patterns.enzh.mp4?v=1793322802-21492026-10-08yes https://exercises.lol/videos/hsk4/not-only-but-also2026-10-30https://exercises.lol/video-media/hsk4/not-only-but-also/not-only-but-also.thumb.jpg?v=1793325118HSK 4 Grammar 26: "Not only … but also …"Not only A, but also B has many frames. Pick a front word, 不但, 不仅 or 不只, and a back word, 而且, 还 or 也. Mix them freely; the real rule is that B must go further…https://exercises.lol/video-media/hsk4/not-only-but-also/not-only-but-also.enzh.mp4?v=1793325118-21502026-10-08yes https://exercises.lol/videos/hsk4/comparing-similar-adverbs2026-10-30https://exercises.lol/video-media/hsk4/comparing-similar-adverbs/comparing-similar-adverbs.thumb.jpg?v=1793323053HSK 4 Grammar 27: Comparing Similar AdverbsSame translation, different jobs. Two "originally"s, two "often"s, two "just"s : each pair hides one clean difference, and finding it ends the confusion. The…https://exercises.lol/video-media/hsk4/comparing-similar-adverbs/comparing-similar-adverbs.enzh.mp4?v=1793323053-21712026-10-08yes https://exercises.lol/videos/hsk4/comparing-similar-prepositions2026-10-30https://exercises.lol/video-media/hsk4/comparing-similar-prepositions/comparing-similar-prepositions.thumb.jpg?v=1793321490HSK 4 Grammar 28: Comparing Similar PrepositionsOne question per pair. Two "about"s, two "from"s : one question settles each: is a feeling attached? Are you measuring or setting off? 关于 compared with 对于…https://exercises.lol/video-media/hsk4/comparing-similar-prepositions/comparing-similar-prepositions.enzh.mp4?v=1793321490-21702026-10-08yes https://exercises.lol/videos/hsk4/comparing-similar-words-one2026-10-30https://exercises.lol/video-media/hsk4/comparing-similar-words-one/comparing-similar-words-one.thumb.jpg?v=1793323125HSK 4 Grammar 29: Comparing Similar Words IThe grammar job decides. Two "opposite"s, three "sure"s, two "suit"s : in every pair, the grammar job decides which word you need. Adverb or adjective. Assert…https://exercises.lol/video-media/hsk4/comparing-similar-words-one/comparing-similar-words-one.enzh.mp4?v=1793323125-21812026-10-08yes https://exercises.lol/videos/hsk4/comparing-similar-words-two2026-10-30https://exercises.lol/video-media/hsk4/comparing-similar-words-two/comparing-similar-words-two.thumb.jpg?v=1793323311HSK 4 Grammar 30: Comparing Similar Words II的时候 places an action during an event; 以后 places it after. The result word 完 is the signpost. An ongoing verb takes 的时候; a completed verb, with 完, takes 以后.https://exercises.lol/video-media/hsk4/comparing-similar-words-two/comparing-similar-words-two.enzh.mp4?v=1793323311-21302026-10-08yes https://exercises.lol/videos/hsk4/say-aloud-opinions-plans2026-10-29https://exercises.lol/video-media/hsk4/say-aloud-opinions-plans/say-aloud-opinions-plans.thumb.jpg?v=1793271754HSK 4 Say it aloud 31: opinions, plans and suggestionsHSK four speaking runs on three frames. The opinion frame: wo renwei, I think, with erqie adding a second leg and buguo cushioning the edge. The plan frame: wo…https://exercises.lol/video-media/hsk4/say-aloud-opinions-plans/say-aloud-opinions-plans.enzh.mp4?v=1793271754-22052026-10-28yes https://exercises.lol/videos/hsk5/adjectives-extreme-and-plenty2026-10-30https://exercises.lol/video-media/hsk5/adjectives-extreme-and-plenty/adjectives-extreme-and-plenty.thumb.jpg?v=1793329255HSK 5 Grammar 1: Adjectives — Extreme and PlentyA busy station gives you four reactions. You miss a seat, the carriage is packed, the snack costs more than you hoped, and the tea is sweeter than you like.…https://exercises.lol/video-media/hsk5/adjectives-extreme-and-plenty/adjectives-extreme-and-plenty.enzh.mp4?v=1793329255-22362026-10-08yes https://exercises.lol/videos/hsk5/adverbs-focus-and-judgment2026-10-30https://exercises.lol/video-media/hsk5/adverbs-focus-and-judgment/adverbs-focus-and-judgment.thumb.jpg?v=1793331214HSK 5 Grammar 2: Adverbs — Focus and JudgmentA late night in the project room. The clock says eleven forty, a classmate's title is wrong, a new teammate joined today, and you nearly missed the last train.…https://exercises.lol/video-media/hsk5/adverbs-focus-and-judgment/adverbs-focus-and-judgment.enzh.mp4?v=1793331214-27002026-10-08yes https://exercises.lol/videos/hsk5/listing-with-a2026-10-30https://exercises.lol/video-media/hsk5/listing-with-a/listing-with-a.thumb.jpg?v=1793325255HSK 5 Grammar 3: Auxiliary Words — Listing with 啊Put 啊 after each item and a list sounds open, spoken and a little unfinished, like what with this, and that, you know. Two or three items are enough. Close…https://exercises.lol/video-media/hsk5/listing-with-a/listing-with-a.enzh.mp4?v=1793325255-21482026-10-08yes https://exercises.lol/videos/hsk5/yao-bu-suggestion2026-10-30https://exercises.lol/video-media/hsk5/yao-bu-suggestion/yao-bu-suggestion.thumb.jpg?v=1793337672HSK 5 Grammar 4: 要不 + Suggestion + 吧要不 puts a plan B on the table and quietly asks whether the other person agrees: how about, why don't we. 吧 at the end keeps the inviting tone: 要不我们去对面那家吧。 It…https://exercises.lol/video-media/hsk5/yao-bu-suggestion/yao-bu-suggestion.enzh.mp4?v=1793337672-21552026-10-08yes https://exercises.lol/videos/hsk5/nouns-and-frames2026-10-30https://exercises.lol/video-media/hsk5/nouns-and-frames/nouns-and-frames.thumb.jpg?v=1793324781HSK 5 Grammar 5: Nouns and Time Frames当中: among, or in the middle. 当中 places someone or something inside a group, a place or a process : "among", "in the centre", "in the middle of an activity".…https://exercises.lol/video-media/hsk5/nouns-and-frames/nouns-and-frames.enzh.mp4?v=1793324781-21932026-10-08yes https://exercises.lol/videos/hsk5/particles-le-ma-ne2026-10-30https://exercises.lol/video-media/hsk5/particles-le-ma-ne/particles-le-ma-ne.thumb.jpg?v=1793325360HSK 5 Grammar 6: Particles了 can sit on the verb or at the end. On the verb, it marks a bounded action: 他关了窗。 He closed the window. At the end, it reports news or a change: 他关窗了。 He's…https://exercises.lol/video-media/hsk5/particles-le-ma-ne/particles-le-ma-ne.enzh.mp4?v=1793325360-21622026-10-08yes https://exercises.lol/videos/hsk5/prepositional-phrases-yi2026-10-30https://exercises.lol/video-media/hsk5/prepositional-phrases-yi/prepositional-phrases-yi.thumb.jpg?v=1793324714HSK 5 Grammar 7: Prepositional PhrasesThe 以 family: four boundaries. 以上; At or above a line; 年收入五万以上 : annual income of 50,000 or more. 以下; At or below a line; 五十元以下 : 50 yuan or less. 以内; Inside a…https://exercises.lol/video-media/hsk5/prepositional-phrases-yi/prepositional-phrases-yi.enzh.mp4?v=1793324714-21042026-10-08yes https://exercises.lol/videos/hsk5/prepositions2026-10-30https://exercises.lol/video-media/hsk5/prepositions/prepositions.thumb.jpg?v=1793329904HSK 5 Grammar 8: Prepositions自从, or 从, marks ever since a point: 自从毕业以来，我一直在北京。 为 before a person names who benefits: 妈妈为我做了晚饭。 And 对, a person, 而言 means as far as they are concerned…https://exercises.lol/video-media/hsk5/prepositions/prepositions.enzh.mp4?v=1793329904-23492026-10-08yes https://exercises.lol/videos/hsk5/focus-and-existence2026-10-30https://exercises.lol/video-media/hsk5/focus-and-existence/focus-and-existence.thumb.jpg?v=1793334740HSK 5 Grammar 9: Sentence Patterns — Focus & Existence要不是 means if it weren't for. The thing that did happen comes first, and the bad result that didn't happen comes second. 要不是你提醒我，我就忘了带钥匙。 If you hadn't reminded…https://exercises.lol/video-media/hsk5/focus-and-existence/focus-and-existence.enzh.mp4?v=1793334740-21492026-10-08yes https://exercises.lol/videos/hsk5/verbs-comparison-and-change2026-11-08https://exercises.lol/video-media/hsk5/verbs-comparison-and-change/verbs-comparison-and-change.thumb.jpg?v=1794122207HSK 5 Grammar 10: Verbs — Comparison and ChangeA verb or adjective plus 什么 pushes back; it is not asking for information. 忙什么，坐下来喝杯茶吧。 What's the rush? Sit down and have some tea. 紧张什么，你准备得很好。 No need to be…https://exercises.lol/video-media/hsk5/verbs-comparison-and-change/verbs-comparison-and-change.enzh.mp4?v=1794122207-22192026-10-08yes https://exercises.lol/videos/hsk5/auxiliary-verbs-jiang2026-10-30https://exercises.lol/video-media/hsk5/auxiliary-verbs-jiang/auxiliary-verbs-jiang.thumb.jpg?v=1793327156HSK 5 Grammar 11: Auxiliary verbsA notice on the clinic board says: 社区诊所将于下周一搬到新址。 The clinic will move next Monday. Friends talking about the same move would say: 下周一要搬家。 The future is the…https://exercises.lol/video-media/hsk5/auxiliary-verbs-jiang/auxiliary-verbs-jiang.enzh.mp4?v=1793327156-22092026-10-08yes https://exercises.lol/videos/hsk5/jiang-formal-future2026-10-30https://exercises.lol/video-media/hsk5/jiang-formal-future/jiang-formal-future.thumb.jpg?v=1793328905HSK 5 Grammar 11: Auxiliary verbsA notice on the clinic board says: 社区诊所将于下周一搬到新址。 The clinic will move next Monday. Friends talking about the same move would say: 下周一要搬家。 The future is the…https://exercises.lol/video-media/hsk5/jiang-formal-future/jiang-formal-future.enzh.mp4?v=1793328905-22092026-10-08yes https://exercises.lol/videos/hsk5/nanyi-shou-verb-phrases2026-10-30https://exercises.lol/video-media/hsk5/nanyi-shou-verb-phrases/nanyi-shou-verb-phrases.thumb.jpg?v=1793321193HSK 5 Grammar 12: Verb phrasesYou join a project team. In week one you mix up two file names, and your teammates take it calmly: 刚换了一份工作，难免会叫错同事的名字。 A month later, your clear summary is…https://exercises.lol/video-media/hsk5/nanyi-shou-verb-phrases/nanyi-shou-verb-phrases.enzh.mp4?v=1793321193-22272026-10-08yes https://exercises.lol/videos/hsk5/verb-phrases-nanyi-shou2026-10-30https://exercises.lol/video-media/hsk5/verb-phrases-nanyi-shou/verb-phrases-nanyi-shou.thumb.jpg?v=1793335074HSK 5 Grammar 12: Verb phrasesYou join a project team. In week one you mix up two file names, and your teammates take it calmly: 刚换了一份工作，难免会叫错同事的名字。 A month later, your clear summary is…https://exercises.lol/video-media/hsk5/verb-phrases-nanyi-shou/verb-phrases-nanyi-shou.enzh.mp4?v=1793335074-22282026-10-08yes https://exercises.lol/videos/hsk5/but-statements-fan-er2026-10-30https://exercises.lol/video-media/hsk5/but-statements-fan-er/but-statements-fan-er.thumb.jpg?v=1793352806HSK 5 Grammar 13: But" statementsYou add more sugar to a cake because you want it to taste better. Your friends take one bite and reach for water. The extra sugar made it worse. That is the…https://exercises.lol/video-media/hsk5/but-statements-fan-er/but-statements-fan-er.enzh.mp4?v=1793352806-22032026-10-08yes https://exercises.lol/videos/hsk5/faner-but-statements2026-10-30https://exercises.lol/video-media/hsk5/faner-but-statements/faner-but-statements.thumb.jpg?v=1793335211HSK 5 Grammar 13: But" statementsYou add more sugar to a cake because you want it to taste better. Your friends take one bite and reach for water. The extra sugar made it worse. That is the…https://exercises.lol/video-media/hsk5/faner-but-statements/faner-but-statements.enzh.mp4?v=1793335211-22032026-10-08yes https://exercises.lol/videos/hsk5/even-if-statements2026-10-30https://exercises.lol/video-media/hsk5/even-if-statements/even-if-statements.thumb.jpg?v=1793326758HSK 5 Grammar 14: Even if" statementsYou and a friend plan a Saturday picnic by the lake. A crowded bus or a grey afternoon might get in the way, but you keep the plan anyway. English calls that…https://exercises.lol/video-media/hsk5/even-if-statements/even-if-statements.enzh.mp4?v=1793326758-22672026-10-08yes https://exercises.lol/videos/hsk5/even-if-three-frames2026-10-30https://exercises.lol/video-media/hsk5/even-if-three-frames/even-if-three-frames.thumb.jpg?v=1793335397HSK 5 Grammar 14: Even if" statementsYou and a friend plan a Saturday picnic by the lake. A crowded bus or a grey afternoon might get in the way, but you keep the plan anyway. English calls that…https://exercises.lol/video-media/hsk5/even-if-three-frames/even-if-three-frames.enzh.mp4?v=1793335397-22642026-10-08yes https://exercises.lol/videos/hsk5/if-statements-jiaru2026-10-30https://exercises.lol/video-media/hsk5/if-statements-jiaru/if-statements-jiaru.thumb.jpg?v=1793321180HSK 5 Grammar 15: If" statementsYou plan a quiet Saturday, but the forecast keeps changing and the library may be full. Chinese has several ways to say if. 假如 sounds deliberate. 万一 raises a…https://exercises.lol/video-media/hsk5/if-statements-jiaru/if-statements-jiaru.enzh.mp4?v=1793321180-22072026-10-08yes https://exercises.lol/videos/hsk5/if-statements-three-frames2026-10-30https://exercises.lol/video-media/hsk5/if-statements-three-frames/if-statements-three-frames.thumb.jpg?v=1793328795HSK 5 Grammar 15: If" statementsYou plan a quiet Saturday, but the forecast keeps changing and the library may be full. Chinese has several ways to say if. 假如 sounds deliberate. 万一 raises a…https://exercises.lol/video-media/hsk5/if-statements-three-frames/if-statements-three-frames.enzh.mp4?v=1793328795-22072026-10-08yes https://exercises.lol/videos/hsk5/gewai-adverbs2026-10-30https://exercises.lol/video-media/hsk5/gewai-adverbs/gewai-adverbs.thumb.jpg?v=1793334348HSK 5 Grammar 16: Adverbs with adjectivesYou take the same bus home every evening. Tonight the city looks calmer than usual: 今天晚上，城市显得格外安静。 格外 means especially or exceptionally. The character 格 means…https://exercises.lol/video-media/hsk5/gewai-adverbs/gewai-adverbs.enzh.mp4?v=1793334348-21532026-10-08yes https://exercises.lol/videos/hsk5/suoyi-cause-effect2026-10-30https://exercises.lol/video-media/hsk5/suoyi-cause-effect/suoyi-cause-effect.thumb.jpg?v=1793334376HSK 5 Grammar 17: Cause & effect statementsYour classmate points at the bus you took and asks why. You could start from the cause: 因为地铁停运了，所以我们改坐公交车。 That follows time. But the question is about the…https://exercises.lol/video-media/hsk5/suoyi-cause-effect/suoyi-cause-effect.enzh.mp4?v=1793334376-21712026-10-08yes https://exercises.lol/videos/hsk5/complements-advanced2026-10-30https://exercises.lol/video-media/hsk5/complements-advanced/complements-advanced.thumb.jpg?v=1793348703HSK 5 Grammar 18: ComplementsCarrying boxes upstairs on a hot Saturday, you need words for extremes. After an adjective, 得 and a short ending push the quality to the top of the scale.…https://exercises.lol/video-media/hsk5/complements-advanced/complements-advanced.enzh.mp4?v=1793348703-23432026-10-08yes https://exercises.lol/videos/hsk5/complements-advanced-set2026-10-30https://exercises.lol/video-media/hsk5/complements-advanced-set/complements-advanced-set.thumb.jpg?v=1793335453HSK 5 Grammar 18: ComplementsCarrying boxes upstairs on a hot Saturday, you need words for extremes. After an adjective, 得 and a short ending push the quality to the top of the scale.…https://exercises.lol/video-media/hsk5/complements-advanced-set/complements-advanced-set.enzh.mp4?v=1793335453-23432026-10-08yes https://exercises.lol/videos/hsk5/yidan-conditionals2026-10-30https://exercises.lol/video-media/hsk5/yidan-conditionals/yidan-conditionals.thumb.jpg?v=1793321493HSK 5 Grammar 19: Conditional statementsYour class plans to leave the café and walk to the museum, but the rain may still be falling. The walk depends on a change: 一旦雨停了，我们就走去博物馆。 Once the rain…https://exercises.lol/video-media/hsk5/yidan-conditionals/yidan-conditionals.enzh.mp4?v=1793321493-21622026-10-08yes https://exercises.lol/videos/hsk5/advanced-sentence-patterns2026-10-30https://exercises.lol/video-media/hsk5/advanced-sentence-patterns/advanced-sentence-patterns.thumb.jpg?v=1793330200HSK 5 Grammar 20: Sentence patterns — advanced把 has four advanced frames. With 给 it adds spoken force: 他把通知给删了。 He went and deleted the notice. With 当成 or 看作 it says how you treat or see something…https://exercises.lol/video-media/hsk5/advanced-sentence-patterns/advanced-sentence-patterns.enzh.mp4?v=1793330200-25992026-10-08yes https://exercises.lol/videos/hsk5/noun-patterns2026-10-30https://exercises.lol/video-media/hsk5/noun-patterns/noun-patterns.thumb.jpg?v=1793334956HSK 5 Grammar 21: Complex sentence patternsYou arrive early and find the classroom door locked. Then a classmate messages that the lesson has moved to Building 3, and suddenly the locked door makes…https://exercises.lol/video-media/hsk5/noun-patterns/noun-patterns.enzh.mp4?v=1793334956-21492026-10-08yes https://exercises.lol/videos/hsk5/noun-patterns-hsk52026-10-30https://exercises.lol/video-media/hsk5/noun-patterns-hsk5/noun-patterns-hsk5.thumb.jpg?v=1793335415HSK 5 Grammar 21: Complex sentence patternsYou arrive early and find the classroom door locked. Then a classmate messages that the lesson has moved to Building 3, and suddenly the locked door makes…https://exercises.lol/video-media/hsk5/noun-patterns-hsk5/noun-patterns-hsk5.enzh.mp4?v=1793335415-21492026-10-08yes https://exercises.lol/videos/hsk5/pronoun-patterns2026-10-30https://exercises.lol/video-media/hsk5/pronoun-patterns/pronoun-patterns.thumb.jpg?v=1793399676HSK 5 Grammar 22: Either… or…One Saturday film ticket is left, and you and your roommate both want it. You state the possibilities: 或者你去，或者我去。 Either you go, or I go. Saying 或者 twice…https://exercises.lol/video-media/hsk5/pronoun-patterns/pronoun-patterns.enzh.mp4?v=1793399676-21412026-10-08yes https://exercises.lol/videos/hsk5/pronoun-patterns-hsk52026-10-30https://exercises.lol/video-media/hsk5/pronoun-patterns-hsk5/pronoun-patterns-hsk5.thumb.jpg?v=1793399626HSK 5 Grammar 22: Either… or…One Saturday film ticket is left, and you and your roommate both want it. You state the possibilities: 或者你去，或者我去。 Either you go, or I go. Saying 或者 twice…https://exercises.lol/video-media/hsk5/pronoun-patterns-hsk5/pronoun-patterns-hsk5.enzh.mp4?v=1793399626-21412026-10-08yes https://exercises.lol/videos/hsk5/sentence-patterns-a2026-10-30https://exercises.lol/video-media/hsk5/sentence-patterns-a/sentence-patterns-a.thumb.jpg?v=1793334108HSK 5 Grammar 23: Let alone…You promised to introduce Friday's talk, but you can't even write a short opening. Chinese can make that point from either end. 别说整篇课文，连今天的生词我都没记住。 Forget the…https://exercises.lol/video-media/hsk5/sentence-patterns-a/sentence-patterns-a.enzh.mp4?v=1793334108-21542026-10-08yes https://exercises.lol/videos/hsk5/sentence-patterns-hsk5-a2026-10-30https://exercises.lol/video-media/hsk5/sentence-patterns-hsk5-a/sentence-patterns-hsk5-a.thumb.jpg?v=1793328007HSK 5 Grammar 23: Let alone…You promised to introduce Friday's talk, but you can't even write a short opening. Chinese can make that point from either end. 别说整篇课文，连今天的生词我都没记住。 Forget the…https://exercises.lol/video-media/hsk5/sentence-patterns-hsk5-a/sentence-patterns-hsk5-a.enzh.mp4?v=1793328007-21532026-10-08yes https://exercises.lol/videos/hsk5/sentence-patterns-b2026-10-30https://exercises.lol/video-media/hsk5/sentence-patterns-b/sentence-patterns-b.thumb.jpg?v=1793334599HSK 5 Grammar 24: Comparing similar adverbs常常 and 经常 both mean often, and before a verb they usually swap freely. 他常常坐地铁去上班。 我们经常在会议室讨论这个计划。 The difference is word class. 经常 can also be an adjective…https://exercises.lol/video-media/hsk5/sentence-patterns-b/sentence-patterns-b.enzh.mp4?v=1793334599-21312026-10-08yes https://exercises.lol/videos/hsk5/sentence-patterns-hsk5-b2026-10-30https://exercises.lol/video-media/hsk5/sentence-patterns-hsk5-b/sentence-patterns-hsk5-b.thumb.jpg?v=1793335057HSK 5 Grammar 24: Comparing similar adverbs常常 and 经常 both mean often, and before a verb they usually swap freely. 他常常坐地铁去上班。 我们经常在会议室讨论这个计划。 The difference is word class. 经常 can also be an adjective…https://exercises.lol/video-media/hsk5/sentence-patterns-hsk5-b/sentence-patterns-hsk5-b.enzh.mp4?v=1793335057-21312026-10-08yes https://exercises.lol/videos/hsk5/complex-patterns2026-10-30https://exercises.lol/video-media/hsk5/complex-patterns/complex-patterns.thumb.jpg?v=1793325613HSK 5 Grammar 25: Comparing similar auxiliary wordsYou wait an hour for a delivery, and when the bag is finally in your hand you laugh with relief. The tracking page only reports that it arrived. Chinese has a…https://exercises.lol/video-media/hsk5/complex-patterns/complex-patterns.enzh.mp4?v=1793325613-21422026-10-08yes https://exercises.lol/videos/hsk5/complex-patterns-hsk52026-10-30https://exercises.lol/video-media/hsk5/complex-patterns-hsk5/complex-patterns-hsk5.thumb.jpg?v=1793327610HSK 5 Grammar 25: Comparing similar auxiliary wordsYou wait an hour for a delivery, and when the bag is finally in your hand you laugh with relief. The tracking page only reports that it arrived. Chinese has a…https://exercises.lol/video-media/hsk5/complex-patterns-hsk5/complex-patterns-hsk5.enzh.mp4?v=1793327610-21422026-10-08yes https://exercises.lol/videos/hsk5/advanced-a2026-10-30https://exercises.lol/video-media/hsk5/advanced-a/advanced-a.thumb.jpg?v=1793334562HSK 5 Grammar 26: Comparing similar conjunctionsEnglish often lets "with" and "to" sound equally right. Chinese makes you choose a picture. 跟 is a two-way link between two sides: 我跟同事一起去爬山。 I go hiking with…https://exercises.lol/video-media/hsk5/advanced-a/advanced-a.enzh.mp4?v=1793334562-22182026-10-08yes https://exercises.lol/videos/hsk5/advanced-patterns-hsk5-a2026-10-30https://exercises.lol/video-media/hsk5/advanced-patterns-hsk5-a/advanced-patterns-hsk5-a.thumb.jpg?v=1793335975HSK 5 Grammar 26: Comparing similar conjunctionsEnglish often lets "with" and "to" sound equally right. Chinese makes you choose a picture. 跟 is a two-way link between two sides: 我跟同事一起去爬山。 I go hiking with…https://exercises.lol/video-media/hsk5/advanced-patterns-hsk5-a/advanced-patterns-hsk5-a.enzh.mp4?v=1793335975-22182026-10-08yes https://exercises.lol/videos/hsk5/advanced-b2026-10-30https://exercises.lol/video-media/hsk5/advanced-b/advanced-b.thumb.jpg?v=1793333951HSK 5 Grammar 27: Comparing similar prepositionsYou meet a friend at a city station. Which way do we walk, which coach goes to the museum? 朝, 向 and 往 all point somewhere. Before a verb of movement they…https://exercises.lol/video-media/hsk5/advanced-b/advanced-b.enzh.mp4?v=1793333951-21662026-10-08yes https://exercises.lol/videos/hsk5/advanced-patterns-hsk5-b2026-10-30https://exercises.lol/video-media/hsk5/advanced-patterns-hsk5-b/advanced-patterns-hsk5-b.thumb.jpg?v=1793325617HSK 5 Grammar 27: Comparing similar prepositionsYou meet a friend at a city station. Which way do we walk, which coach goes to the museum? 朝, 向 and 往 all point somewhere. Before a verb of movement they…https://exercises.lol/video-media/hsk5/advanced-patterns-hsk5-b/advanced-patterns-hsk5-b.enzh.mp4?v=1793325617-21642026-10-08yes https://exercises.lol/videos/hsk5/advanced-c2026-10-30https://exercises.lol/video-media/hsk5/advanced-c/advanced-c.thumb.jpg?v=1793336170HSK 5 Grammar 28: Comparing similar time wordsYou tell a friend how your evenings usually go. 平时 and 平常 both mean usually, and before a verb you can swap them: 她平时坐地铁上班。 她平常坐地铁上班。 But only 平常 is also an…https://exercises.lol/video-media/hsk5/advanced-c/advanced-c.enzh.mp4?v=1793336170-21382026-10-08yes https://exercises.lol/videos/hsk5/advanced-patterns-hsk5-c2026-10-30https://exercises.lol/video-media/hsk5/advanced-patterns-hsk5-c/advanced-patterns-hsk5-c.thumb.jpg?v=1793327156HSK 5 Grammar 28: Comparing similar time wordsYou tell a friend how your evenings usually go. 平时 and 平常 both mean usually, and before a verb you can swap them: 她平时坐地铁上班。 她平常坐地铁上班。 But only 平常 is also an…https://exercises.lol/video-media/hsk5/advanced-patterns-hsk5-c/advanced-patterns-hsk5-c.enzh.mp4?v=1793327156-21362026-10-08yes https://exercises.lol/videos/hsk5/advanced-d2026-10-30https://exercises.lol/video-media/hsk5/advanced-d/advanced-d.thumb.jpg?v=1793335187HSK 5 Grammar 29: Comparing similar verbsOutside a noodle shop, the shutter is half down and the inside is dark. First you describe what you see: 这家面馆的灯都关着，看起来还没营业。 It looks as if it isn't open yet.…https://exercises.lol/video-media/hsk5/advanced-d/advanced-d.enzh.mp4?v=1793335187-21342026-10-08yes https://exercises.lol/videos/hsk5/advanced-patterns-hsk5-d2026-10-30https://exercises.lol/video-media/hsk5/advanced-patterns-hsk5-d/advanced-patterns-hsk5-d.thumb.jpg?v=1793327613HSK 5 Grammar 29: Comparing similar verbsOutside a noodle shop, the shutter is half down and the inside is dark. First you describe what you see: 这家面馆的灯都关着，看起来还没营业。 It looks as if it isn't open yet.…https://exercises.lol/video-media/hsk5/advanced-patterns-hsk5-d/advanced-patterns-hsk5-d.enzh.mp4?v=1793327613-21342026-10-08yes https://exercises.lol/videos/hsk5/say-aloud-discussions2026-10-29https://exercises.lol/video-media/hsk5/say-aloud-discussions/say-aloud-discussions.thumb.jpg?v=1793271627HSK 5 Say it aloud 30: discussions, explanations and presentationsHSK five speaking takes the chair. In discussion, agree and then extend: wo tongyi, lingwai, agreeing keeps the peace and extending keeps the floor. In…https://exercises.lol/video-media/hsk5/say-aloud-discussions/say-aloud-discussions.enzh.mp4?v=1793271627-21792026-10-28yes https://exercises.lol/videos/hsk6/adverbs-judgment-and-scope2026-10-29https://exercises.lol/video-media/hsk6/adverbs-judgment-and-scope/adverbs-judgment-and-scope.thumb.jpg?v=1793309391HSK 6 Grammar 1: Adverbs of Judgment and ScopeIn speech, 倒 after 得 turns the adjective sour. Someone calls a job easy, and you know it isn't: 你说得倒容易，真正上台演示的人是我。 Easy for you to say; I'm the one presenting.…https://exercises.lol/video-media/hsk6/adverbs-judgment-and-scope/adverbs-judgment-and-scope.enzh.mp4?v=1793309391-24812026-10-08yes https://exercises.lol/videos/hsk6/topic-012026-10-29https://exercises.lol/video-media/hsk6/topic-01/topic-01.thumb.jpg?v=1793295598HSK 6 Grammar 1: Adverbs of Judgment and ScopeIn speech, 倒 after 得 turns the adjective sour. Someone calls a job easy, and you know it isn't: 你说得倒容易，真正上台演示的人是我。 Easy for you to say; I'm the one presenting.…https://exercises.lol/video-media/hsk6/topic-01/topic-01.enzh.mp4?v=1793295598-24792026-10-08yes https://exercises.lol/videos/hsk6/sentence-laizhe2026-10-30https://exercises.lol/video-media/hsk6/sentence-laizhe/sentence-laizhe.thumb.jpg?v=1793339170HSK 6 Grammar 2: Sentence + 来着You stop halfway down the stairs. A classmate just told you the room number, and it has already slipped. 来着 is the casual tag for I had it a second ago. It…https://exercises.lol/video-media/hsk6/sentence-laizhe/sentence-laizhe.enzh.mp4?v=1793339170-21222026-10-08yes https://exercises.lol/videos/hsk6/topic-022026-10-30https://exercises.lol/video-media/hsk6/topic-02/topic-02.thumb.jpg?v=1793325331HSK 6 Grammar 2: Sentence + 来着You stop halfway down the stairs. A classmate just told you the room number, and it has already slipped. 来着 is the casual tag for I had it a second ago. It…https://exercises.lol/video-media/hsk6/topic-02/topic-02.enzh.mp4?v=1793325331-21222026-10-08yes https://exercises.lol/videos/hsk6/connectors-formal2026-10-30https://exercises.lol/video-media/hsk6/connectors-formal/connectors-formal.thumb.jpg?v=1793339796HSK 6 Grammar 3: 免得, 以及, 总之, 则A team is emailing clients about a new date. Four words keep the note clear and formal. 以免 names trouble you are keeping away. 以及 adds an extra item. 总之 gives…https://exercises.lol/video-media/hsk6/connectors-formal/connectors-formal.enzh.mp4?v=1793339796-21932026-10-08yes https://exercises.lol/videos/hsk6/topic-032026-10-30https://exercises.lol/video-media/hsk6/topic-03/topic-03.thumb.jpg?v=1793326250HSK 6 Grammar 3: 免得, 以及, 总之, 则A team is emailing clients about a new date. Four words keep the note clear and formal. 以免 names trouble you are keeping away. 以及 adds an extra item. 总之 gives…https://exercises.lol/video-media/hsk6/topic-03/topic-03.enzh.mp4?v=1793326250-21932026-10-08yes https://exercises.lol/videos/hsk6/ben-and-xing2026-10-30https://exercises.lol/video-media/hsk6/ben-and-xing/ben-and-xing.thumb.jpg?v=1793325610HSK 6 Grammar 4: 本 + 名词, 词 + 性The school office announces a Friday closure in a stiff official voice, speaking as the school itself: 本校本周五停课一天。 A classmate forwards the same news casually…https://exercises.lol/video-media/hsk6/ben-and-xing/ben-and-xing.enzh.mp4?v=1793325610-21392026-10-08yes https://exercises.lol/videos/hsk6/topic-042026-10-30https://exercises.lol/video-media/hsk6/topic-04/topic-04.thumb.jpg?v=1793331870HSK 6 Grammar 4: 本 + 名词, 词 + 性The school office announces a Friday closure in a stiff official voice, speaking as the school itself: 本校本周五停课一天。 A classmate forwards the same news casually…https://exercises.lol/video-media/hsk6/topic-04/topic-04.enzh.mp4?v=1793331870-21392026-10-08yes https://exercises.lol/videos/hsk6/shi-fou-particles2026-10-30https://exercises.lol/video-media/hsk6/shi-fou-particles/shi-fou-particles.thumb.jpg?v=1793339785HSK 6 Grammar 5: 是否, 与否, 之, 嘛, 呗In one afternoon, a form asks whether your phone number is still correct, and a friend writes that the next step is obvious. Writing and speech use different…https://exercises.lol/video-media/hsk6/shi-fou-particles/shi-fou-particles.enzh.mp4?v=1793339785-22042026-10-08yes https://exercises.lol/videos/hsk6/topic-052026-10-28https://exercises.lol/video-media/hsk6/topic-05/topic-05.thumb.jpg?v=1793209339HSK 6 Grammar 5: 是否, 与否, 之, 嘛, 呗In one afternoon, a form asks whether your phone number is still correct, and a friend writes that the next step is obvious. Writing and speech use different…https://exercises.lol/video-media/hsk6/topic-05/topic-05.enzh.mp4?v=1793209339-22042026-10-08yes https://exercises.lol/videos/hsk6/jianyu-formal2026-10-30https://exercises.lol/video-media/hsk6/jianyu-formal/jianyu-formal.thumb.jpg?v=1793333422HSK 6 Grammar 6: 鉴于After an hour on the noisy site next door, the chair of the meeting states the fact the group has considered, and the step it will take. That two-part move is…https://exercises.lol/video-media/hsk6/jianyu-formal/jianyu-formal.enzh.mp4?v=1793333422-21352026-10-08yes https://exercises.lol/videos/hsk6/topic-062026-10-30https://exercises.lol/video-media/hsk6/topic-06/topic-06.thumb.jpg?v=1793323408HSK 6 Grammar 6: 鉴于After an hour on the noisy site next door, the chair of the meeting states the fact the group has considered, and the step it will take. That two-part move is…https://exercises.lol/video-media/hsk6/topic-06/topic-06.enzh.mp4?v=1793323408-21352026-10-08yes https://exercises.lol/videos/hsk6/advanced-patterns-hsk62026-10-30https://exercises.lol/video-media/hsk6/advanced-patterns-hsk6/advanced-patterns-hsk6.thumb.jpg?v=1793353125HSK 6 Grammar 7: Advanced patternsMina already believes that redoing the poster tonight is a bad idea, and she pushes the group to agree: 都十一点了，现在重做海报岂不是更耽误事？ It's eleven already; wouldn't…https://exercises.lol/video-media/hsk6/advanced-patterns-hsk6/advanced-patterns-hsk6.enzh.mp4?v=1793353125-23952026-10-08yes https://exercises.lol/videos/hsk6/topic-072026-10-30https://exercises.lol/video-media/hsk6/topic-07/topic-07.thumb.jpg?v=1793348460HSK 6 Grammar 7: Advanced patternsMina already believes that redoing the poster tonight is a bad idea, and she pushes the group to agree: 都十一点了，现在重做海报岂不是更耽误事？ It's eleven already; wouldn't…https://exercises.lol/video-media/hsk6/topic-07/topic-07.enzh.mp4?v=1793348460-23952026-10-08yes https://exercises.lol/videos/hsk6/liang-bet-guess2026-10-30https://exercises.lol/video-media/hsk6/liang-bet-guess/liang-bet-guess.thumb.jpg?v=1793338700HSK 6 Grammar 8: 谅 + Subject + Verb PhraseYour roommate has spent three nights complaining about the karaoke upstairs. You offer to go up together, and suddenly they find a cup that needs washing. You…https://exercises.lol/video-media/hsk6/liang-bet-guess/liang-bet-guess.enzh.mp4?v=1793338700-21362026-10-08yes https://exercises.lol/videos/hsk6/topic-082026-10-30https://exercises.lol/video-media/hsk6/topic-08/topic-08.thumb.jpg?v=1793331683HSK 6 Grammar 8: 谅 + Subject + Verb PhraseYour roommate has spent three nights complaining about the karaoke upstairs. You offer to go up together, and suddenly they find a cup that needs washing. You…https://exercises.lol/video-media/hsk6/topic-08/topic-08.enzh.mp4?v=1793331683-21362026-10-08yes https://exercises.lol/videos/hsk6/buxie-yubian-goal2026-10-30https://exercises.lol/video-media/hsk6/buxie-yubian-goal/buxie-yubian-goal.thumb.jpg?v=1793325138HSK 6 Grammar 9: 不屑 and 以便Lin's team was ready to publish a post that reused a rival's sentences. She refused: 林不屑于抄别人的句子。 Copying sat below the job. Then she listed every source at the…https://exercises.lol/video-media/hsk6/buxie-yubian-goal/buxie-yubian-goal.enzh.mp4?v=1793325138-21522026-10-08yes https://exercises.lol/videos/hsk6/topic-092026-10-30https://exercises.lol/video-media/hsk6/topic-09/topic-09.thumb.jpg?v=1793332558HSK 6 Grammar 9: 不屑 and 以便Lin's team was ready to publish a post that reused a rival's sentences. She refused: 林不屑于抄别人的句子。 Copying sat below the job. Then she listed every source at the…https://exercises.lol/video-media/hsk6/topic-09/topic-09.enzh.mp4?v=1793332558-21522026-10-08yes https://exercises.lol/videos/hsk6/jiashi-formal-if2026-10-30https://exercises.lol/video-media/hsk6/jiashi-formal-if/jiashi-formal-if.thumb.jpg?v=1793339159HSK 6 Grammar 10: 假使You are writing a school-paper article about a river clean-up, and you want readers to imagine what happens if nobody joins. To a classmate you'd say…https://exercises.lol/video-media/hsk6/jiashi-formal-if/jiashi-formal-if.enzh.mp4?v=1793339159-21362026-10-08yes https://exercises.lol/videos/hsk6/topic-102026-10-30https://exercises.lol/video-media/hsk6/topic-10/topic-10.thumb.jpg?v=1793324712HSK 6 Grammar 10: 假使You are writing a school-paper article about a river clean-up, and you want readers to imagine what happens if nobody joins. To a classmate you'd say…https://exercises.lol/video-media/hsk6/topic-10/topic-10.enzh.mp4?v=1793324712-21362026-10-08yes https://exercises.lol/videos/hsk6/topic-112026-10-30https://exercises.lol/video-media/hsk6/topic-11/topic-11.thumb.jpg?v=1793324964HSK 6 Grammar 11: 因…而A project report ties late nights to a delay: the cause leads, and the result follows. That is the frame 因, or 因为, then 而. 这条老街因为施工而暂时封闭。 This old street is…https://exercises.lol/video-media/hsk6/topic-11/topic-11.enzh.mp4?v=1793324964-21272026-10-08yes https://exercises.lol/videos/hsk6/yin-er-formal-cause2026-10-29https://exercises.lol/video-media/hsk6/yin-er-formal-cause/yin-er-formal-cause.thumb.jpg?v=1793313579HSK 6 Grammar 11: 因…而A project report ties late nights to a delay: the cause leads, and the result follows. That is the frame 因, or 因为, then 而. 这条老街因为施工而暂时封闭。 This old street is…https://exercises.lol/video-media/hsk6/yin-er-formal-cause/yin-er-formal-cause.enzh.mp4?v=1793313579-21272026-10-08yes https://exercises.lol/videos/hsk6/formal-patterns-set2026-10-30https://exercises.lol/video-media/hsk6/formal-patterns-set/formal-patterns-set.thumb.jpg?v=1793339200HSK 6 Grammar 12: Formal patternsYou are writing a project report and a polite email to the people who funded the work. In speech, 如果, 所以 and 为了 are enough. Formal writing prefers tighter…https://exercises.lol/video-media/hsk6/formal-patterns-set/formal-patterns-set.enzh.mp4?v=1793339200-23112026-10-08yes https://exercises.lol/videos/hsk6/topic-122026-10-30https://exercises.lol/video-media/hsk6/topic-12/topic-12.thumb.jpg?v=1793330907HSK 6 Grammar 12: Formal patternsYou are writing a project report and a polite email to the people who funded the work. In speech, 如果, 所以 and 为了 are enough. Formal writing prefers tighter…https://exercises.lol/video-media/hsk6/topic-12/topic-12.enzh.mp4?v=1793330907-23112026-10-08yes https://exercises.lol/videos/hsk6/lian-hekuang-escalate2026-10-30https://exercises.lol/video-media/hsk6/lian-hekuang-escalate/lian-hekuang-escalate.thumb.jpg?v=1793338563HSK 6 Grammar 13: 连…何况The best reader in your class still can't finish this article, and a classmate wants the new students to summarise it tomorrow. You need a sentence that…https://exercises.lol/video-media/hsk6/lian-hekuang-escalate/lian-hekuang-escalate.enzh.mp4?v=1793338563-21442026-10-08yes https://exercises.lol/videos/hsk6/topic-132026-10-30https://exercises.lol/video-media/hsk6/topic-13/topic-13.thumb.jpg?v=1793352961HSK 6 Grammar 13: 连…何况The best reader in your class still can't finish this article, and a classmate wants the new students to summarise it tomorrow. You need a sentence that…https://exercises.lol/video-media/hsk6/topic-13/topic-13.enzh.mp4?v=1793352961-21472026-10-08yes https://exercises.lol/videos/hsk6/confusable-pairs-hsk62026-10-30https://exercises.lol/video-media/hsk6/confusable-pairs-hsk6/confusable-pairs-hsk6.thumb.jpg?v=1793339614HSK 6 Grammar 14: Confusable pairsYour team trip is off. The office notice tells everyone to follow the written plan, while a friend guesses from a weather app. 按照 means you follow a rule or…https://exercises.lol/video-media/hsk6/confusable-pairs-hsk6/confusable-pairs-hsk6.enzh.mp4?v=1793339614-23542026-10-08yes https://exercises.lol/videos/hsk6/topic-142026-10-30https://exercises.lol/video-media/hsk6/topic-14/topic-14.thumb.jpg?v=1793348474HSK 6 Grammar 14: Confusable pairsYour team trip is off. The office notice tells everyone to follow the written plan, while a friend guesses from a weather app. 按照 means you follow a rule or…https://exercises.lol/video-media/hsk6/topic-14/topic-14.enzh.mp4?v=1793348474-23542026-10-08yes https://exercises.lol/videos/hsk6/bici-duifang-renjia-pronouns2026-10-30https://exercises.lol/video-media/hsk6/bici-duifang-renjia-pronouns/bici-duifang-renjia-pronouns.thumb.jpg?v=1793338473HSK 6 Grammar 15: 彼此 vs 对方, 人家 vs 别人Two roommates have fallen out over the dishes, and a neighbour joins in. English has each other and other people. Chinese uses two pairs. 彼此 is mutual: both…https://exercises.lol/video-media/hsk6/bici-duifang-renjia-pronouns/bici-duifang-renjia-pronouns.enzh.mp4?v=1793338473-21382026-10-08yes https://exercises.lol/videos/hsk6/topic-152026-10-30https://exercises.lol/video-media/hsk6/topic-15/topic-15.thumb.jpg?v=1793352780HSK 6 Grammar 15: 彼此 vs 对方, 人家 vs 别人Two roommates have fallen out over the dishes, and a neighbour joins in. English has each other and other people. Chinese uses two pairs. 彼此 is mutual: both…https://exercises.lol/video-media/hsk6/topic-15/topic-15.enzh.mp4?v=1793352780-21382026-10-08yes https://exercises.lol/videos/hsk6/say-aloud-argument2026-10-29https://exercises.lol/video-media/hsk6/say-aloud-argument/say-aloud-argument.thumb.jpg?v=1793271804HSK 6 Say it aloud 16: argument, summary and formal presentationHSK six speaking argues. Yuqi shuo, buru shuo, rather than saying X, better to say Y, reframes the question itself. Heikuang piles a second reason onto an…https://exercises.lol/video-media/hsk6/say-aloud-argument/say-aloud-argument.enzh.mp4?v=1793271804-22012026-10-28yes https://exercises.lol/videos/ib_anthropology_hl/topic-012026-10-30https://exercises.lol/video-media/ib_anthropology_hl/topic-01/topic-01.thumb.jpg?v=1793392270Engaging with anthropologyIn 1956 the anthropologist Horace Miner described a people called the Nacirema. Every house has a shrine with a magic box, people perform daily mouth rites…https://exercises.lol/video-media/ib_anthropology_hl/topic-01/topic-01.enzh.mp4?v=1793392270-23032026-10-27yes https://exercises.lol/videos/ib_anthropology_hl/topic-022026-10-30https://exercises.lol/video-media/ib_anthropology_hl/topic-02/topic-02.thumb.jpg?v=1793396340Engaging with ethnographyIn the Trobriand Islands, Malinowski watched men sail for days across open sea, risking storms, to give away necklaces of red shell. Months later they received…https://exercises.lol/video-media/ib_anthropology_hl/topic-02/topic-02.enzh.mp4?v=1793396340-22632026-10-28yes https://exercises.lol/videos/ib_anthropology_hl/topic-032026-10-30https://exercises.lol/video-media/ib_anthropology_hl/topic-03/topic-03.thumb.jpg?v=1793396523Anthropological practiceIn 1958 Clifford Geertz and his wife arrived in a village in Bali. For days the villagers ignored them, as if they were invisible. Then they went to watch a…https://exercises.lol/video-media/ib_anthropology_hl/topic-03/topic-03.enzh.mp4?v=1793396523-22152026-10-28yes https://exercises.lol/videos/ib_anthropology_hl/topic-042026-10-30https://exercises.lol/video-media/ib_anthropology_hl/topic-04/topic-04.thumb.jpg?v=1793396214HL extension: theoryIn 2007 the United States Army began the Human Terrain System. It placed social scientists, including anthropologists, with army units in Iraq and Afghanistan…https://exercises.lol/video-media/ib_anthropology_hl/topic-04/topic-04.enzh.mp4?v=1793396214-22482026-10-28yes https://exercises.lol/videos/ib_anthropology_sl/topic-012026-10-30https://exercises.lol/video-media/ib_anthropology_sl/topic-01/topic-01.thumb.jpg?v=1793393885Engaging with anthropologyIn 1956 the anthropologist Horace Miner described a people called the Nacirema. Every house has a shrine with a magic box, people perform daily mouth rites…https://exercises.lol/video-media/ib_anthropology_sl/topic-01/topic-01.enzh.mp4?v=1793393885-23032026-10-27yes https://exercises.lol/videos/ib_anthropology_sl/topic-022026-10-30https://exercises.lol/video-media/ib_anthropology_sl/topic-02/topic-02.thumb.jpg?v=1793396384Engaging with ethnographyIn the Trobriand Islands, Malinowski watched men sail for days across open sea, risking storms, to give away necklaces of red shell. Months later they received…https://exercises.lol/video-media/ib_anthropology_sl/topic-02/topic-02.enzh.mp4?v=1793396384-22632026-10-28yes https://exercises.lol/videos/ib_anthropology_sl/topic-032026-10-30https://exercises.lol/video-media/ib_anthropology_sl/topic-03/topic-03.thumb.jpg?v=1793396528Anthropological practiceIn 1958 Clifford Geertz and his wife arrived in a village in Bali. For days the villagers ignored them, as if they were invisible. Then they went to watch a…https://exercises.lol/video-media/ib_anthropology_sl/topic-03/topic-03.enzh.mp4?v=1793396528-22152026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-012026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-01/supported-focus-01.thumb.jpg?v=1793272850WaterA water droplet holds together on a leaf. Its behaviour comes from interactions between molecules, not a skin made of solid water.https://exercises.lol/video-media/ib_biology_hl/supported-focus-01/supported-focus-01.enzh.mp4?v=1793272850-22462026-10-29yes https://exercises.lol/videos/ib_biology_hl/supported-focus-022026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-02/supported-focus-02.thumb.jpg?v=1793273138Nucleic acidsA change in DNA can affect a protein, but not every DNA change changes the amino-acid sequence. The effect depends on the sequence and how it is used.https://exercises.lol/video-media/ib_biology_hl/supported-focus-02/supported-focus-02.enzh.mp4?v=1793273138-22362026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-032026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-03/supported-focus-03.thumb.jpg?v=1793273604Origins of cellsMitochondria have their own DNA and divide within cells. These features invite an evolutionary explanation that can be tested against other evidence.https://exercises.lol/video-media/ib_biology_hl/supported-focus-03/supported-focus-03.enzh.mp4?v=1793273604-22362026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-042026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-04/supported-focus-04.thumb.jpg?v=1793273403Cell structureA cell can look larger on a screen without changing its real size. Two photographs at different zoom settings cannot be compared by eye alone.https://exercises.lol/video-media/ib_biology_hl/supported-focus-04/supported-focus-04.enzh.mp4?v=1793273403-22272026-10-29yes https://exercises.lol/videos/ib_biology_hl/supported-focus-052026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-05/supported-focus-05.thumb.jpg?v=1793273762VirusesAn antibiotic may help against a bacterial infection but fail against a viral illness. Treatment depends on the causal organism and the evidence supporting…https://exercises.lol/video-media/ib_biology_hl/supported-focus-05/supported-focus-05.enzh.mp4?v=1793273762-22252026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-062026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-06/supported-focus-06.thumb.jpg?v=1793274013Diversity of organismsTwo species look similar but their DNA comparison places them in different branches. Classification uses several kinds of evidence rather than appearance alone.https://exercises.lol/video-media/ib_biology_hl/supported-focus-06/supported-focus-06.enzh.mp4?v=1793274013-22062026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-082026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-08/supported-focus-08.thumb.jpg?v=1793274256Evolution and speciationLeaves in dry environments often have features that reduce water loss. The value of a feature depends on environmental conditions and trade-offs.https://exercises.lol/video-media/ib_biology_hl/supported-focus-08/supported-focus-08.enzh.mp4?v=1793274256-22382026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-092026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-09/supported-focus-09.thumb.jpg?v=1793274357Conservation of biodiversityA site with many individuals can still be dominated by one species. Abundance, richness and evenness 均匀度 describe different features of biodiversity.https://exercises.lol/video-media/ib_biology_hl/supported-focus-09/supported-focus-09.enzh.mp4?v=1793274357-22242026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-102026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-10/supported-focus-10.thumb.jpg?v=1793275016Carbohydrates and lipidsStarch, a triglyceride and a protein can all contain carbon, hydrogen and oxygen, yet their structures and functions differ. An element list alone does not…https://exercises.lol/video-media/ib_biology_hl/supported-focus-10/supported-focus-10.enzh.mp4?v=1793275016-22752026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-122026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-12/supported-focus-12.thumb.jpg?v=1793274767Membranes and membrane transportA potato cylinder gains mass in one solution and loses mass in another. Its mass change provides evidence about movement of water, rather than movement of…https://exercises.lol/video-media/ib_biology_hl/supported-focus-12/supported-focus-12.enzh.mp4?v=1793274767-22542026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-142026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-14/supported-focus-14.thumb.jpg?v=1793275155Cell specializationA root-hair cell and a red blood cell have different shapes because their functions impose different demands.https://exercises.lol/video-media/ib_biology_hl/supported-focus-14/supported-focus-14.enzh.mp4?v=1793275155-22262026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-152026-10-28https://exercises.lol/video-media/ib_biology_hl/supported-focus-15/supported-focus-15.thumb.jpg?v=1793197248Gas exchangeAn exchange surface can be very thin yet fail to deliver enough oxygen when ventilation 通气 or blood flow falls.https://exercises.lol/video-media/ib_biology_hl/supported-focus-15/supported-focus-15.enzh.mp4?v=1793197248-22382026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-162026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-16/supported-focus-16.thumb.jpg?v=1793275452TransportTwo foods can have the same mass but provide different nutrients. A health claim must distinguish the nutrient measured from the health outcome inferred.https://exercises.lol/video-media/ib_biology_hl/supported-focus-16/supported-focus-16.enzh.mp4?v=1793275452-22322026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-172026-10-30https://exercises.lol/video-media/ib_biology_hl/supported-focus-17/supported-focus-17.thumb.jpg?v=1793366835Muscle and motilityA sarcomere 肌节 becomes shorter during contraction although its thick and thin filaments keep approximately the same length.https://exercises.lol/video-media/ib_biology_hl/supported-focus-17/supported-focus-17.enzh.mp4?v=1793366835-22202026-10-24yes https://exercises.lol/videos/ib_biology_hl/supported-focus-192026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-19/supported-focus-19.thumb.jpg?v=1793275739Ecological nichesTwo species can share a habitat while using different resources or using the same resource at different times. A niche describes more than a location.https://exercises.lol/video-media/ib_biology_hl/supported-focus-19/supported-focus-19.enzh.mp4?v=1793275739-22682026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-202026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-20/supported-focus-20.thumb.jpg?v=1793275883Enzymes and metabolismAn enzyme 酶 works quickly at one temperature and slowly at another. Heating can increase successful collisions, but excessive heat can change the active site.https://exercises.lol/video-media/ib_biology_hl/supported-focus-20/supported-focus-20.enzh.mp4?v=1793275883-22322026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-212026-10-30https://exercises.lol/video-media/ib_biology_hl/supported-focus-21/supported-focus-21.thumb.jpg?v=1793367714Cell respirationA muscle can use oxygen while you exercise without producing a flame. Respiration 呼吸作用 transfers energy through a controlled series of reactions.https://exercises.lol/video-media/ib_biology_hl/supported-focus-21/supported-focus-21.enzh.mp4?v=1793367714-22762026-10-30yes https://exercises.lol/videos/ib_biology_hl/supported-focus-222026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-22/supported-focus-22.thumb.jpg?v=1793276028PhotosynthesisA brighter lamp does not always produce more oxygen from pondweed. Another factor may limit the process when light is already sufficient.https://exercises.lol/video-media/ib_biology_hl/supported-focus-22/supported-focus-22.enzh.mp4?v=1793276028-22322026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-232026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-23/supported-focus-23.thumb.jpg?v=1793246276Chemical signallingTwo cell types encounter the same signal but respond differently. Their receptors 受体 and internal pathways determine what follows.https://exercises.lol/video-media/ib_biology_hl/supported-focus-23/supported-focus-23.enzh.mp4?v=1793246276-22202026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-242026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-24/supported-focus-24.thumb.jpg?v=1793246276Neural signallingA stronger stimulus can increase impulse frequency while each action potential 动作电位 remains a similar size.https://exercises.lol/video-media/ib_biology_hl/supported-focus-24/supported-focus-24.enzh.mp4?v=1793246276-22302026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-252026-10-30https://exercises.lol/video-media/ib_biology_hl/supported-focus-25/supported-focus-25.thumb.jpg?v=1793366833Integration of body systemsBlood glucose rises after a meal, but usually does not keep rising indefinitely. A control system responds to the change in internal conditions.https://exercises.lol/video-media/ib_biology_hl/supported-focus-25/supported-focus-25.enzh.mp4?v=1793366833-22362026-10-24yes https://exercises.lol/videos/ib_biology_hl/supported-focus-272026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-27/supported-focus-27.thumb.jpg?v=1793276194Populations and communitiesA field edge looks richer in plants than its centre. Choosing only the richest patches would build the desired result into the sampling method.https://exercises.lol/video-media/ib_biology_hl/supported-focus-27/supported-focus-27.enzh.mp4?v=1793276194-22382026-10-29yes https://exercises.lol/videos/ib_biology_hl/supported-focus-282026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-28/supported-focus-28.thumb.jpg?v=1793276367Transfer of energy and matterEnergy available as new biomass usually decreases along a food chain. Energy is conserved overall, but some transferred energy leaves the next-level production…https://exercises.lol/video-media/ib_biology_hl/supported-focus-28/supported-focus-28.enzh.mp4?v=1793276367-22842026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-292026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-29/supported-focus-29.thumb.jpg?v=1793276444DNA replicationAfter DNA replication, each daughter double helix contains one pre-existing strand and one newly synthesized strand. Copying a molecule is different from…https://exercises.lol/video-media/ib_biology_hl/supported-focus-29/supported-focus-29.enzh.mp4?v=1793276444-22722026-10-29yes https://exercises.lol/videos/ib_biology_hl/supported-focus-322026-10-28https://exercises.lol/video-media/ib_biology_hl/supported-focus-32/supported-focus-32.thumb.jpg?v=1793198369Cell and nuclear divisionA root-tip image contains cells at different stages of mitosis. A snapshot can estimate the fraction of cells dividing, but it does not time one observed cell…https://exercises.lol/video-media/ib_biology_hl/supported-focus-32/supported-focus-32.enzh.mp4?v=1793198369-22312026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-332026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-33/supported-focus-33.thumb.jpg?v=1793276514Gene expressionTwo cells with the same genome make different proteins. Regulation changes which information is used and when.https://exercises.lol/video-media/ib_biology_hl/supported-focus-33/supported-focus-33.enzh.mp4?v=1793276514-22172026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-342026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-34/supported-focus-34.thumb.jpg?v=1793276717Water potentialA plant cell can stop gaining net water even while its contents contain solute. The cell wall permits pressure to build, altering the water-potential 水势…https://exercises.lol/video-media/ib_biology_hl/supported-focus-34/supported-focus-34.enzh.mp4?v=1793276717-23062026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-352026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-35/supported-focus-35.thumb.jpg?v=1793276757ReproductionGametes normally contain one set of chromosomes, while fertilization 受精 joins two sets. Maintaining chromosome number across generations requires both…https://exercises.lol/video-media/ib_biology_hl/supported-focus-35/supported-focus-35.enzh.mp4?v=1793276757-22862026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-362026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-36/supported-focus-36.thumb.jpg?v=1793276848InheritanceTwo parents can carry a recessive allele 等位基因 without expressing the associated phenotype. Their children do not have to match the parents phenotypically.https://exercises.lol/video-media/ib_biology_hl/supported-focus-36/supported-focus-36.enzh.mp4?v=1793276848-22332026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-402026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-40/supported-focus-40.thumb.jpg?v=1793276994Climate changeOne cold day does not disprove a warming climate. Weather describes short-term conditions; climate describes distributions over longer times and regions.https://exercises.lol/video-media/ib_biology_hl/supported-focus-40/supported-focus-40.enzh.mp4?v=1793276994-22512026-10-28yes https://exercises.lol/videos/ib_biology_hl/supported-focus-412026-10-29https://exercises.lol/video-media/ib_biology_hl/supported-focus-41/supported-focus-41.thumb.jpg?v=1793276965Experimental programmeA line passing near every data point is useful, but its gradient can still be uncertain. A graph is evidence for a model within the measurement range.https://exercises.lol/video-media/ib_biology_hl/supported-focus-41/supported-focus-41.enzh.mp4?v=1793276965-22452026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-012026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-01/supported-focus-01.thumb.jpg?v=1793277067WaterA water droplet holds together on a leaf. Its behaviour comes from interactions between molecules, not a skin made of solid water.https://exercises.lol/video-media/ib_biology_sl/supported-focus-01/supported-focus-01.enzh.mp4?v=1793277067-22452026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-022026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-02/supported-focus-02.thumb.jpg?v=1793247263Nucleic acidsA change in DNA can affect a protein, but not every DNA change changes the amino-acid sequence. The effect depends on the sequence and how it is used.https://exercises.lol/video-media/ib_biology_sl/supported-focus-02/supported-focus-02.enzh.mp4?v=1793247263-22372026-10-29yes https://exercises.lol/videos/ib_biology_sl/supported-focus-032026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-03/supported-focus-03.thumb.jpg?v=1793247329Cell structureA cell can look larger on a screen without changing its real size. Two photographs at different zoom settings cannot be compared by eye alone.https://exercises.lol/video-media/ib_biology_sl/supported-focus-03/supported-focus-03.enzh.mp4?v=1793247329-22292026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-042026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-04/supported-focus-04.thumb.jpg?v=1793277728Diversity of organismsTwo species look similar but their DNA comparison places them in different branches. Classification uses several kinds of evidence rather than appearance alone.https://exercises.lol/video-media/ib_biology_sl/supported-focus-04/supported-focus-04.enzh.mp4?v=1793277728-22092026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-052026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-05/supported-focus-05.thumb.jpg?v=1793277235Evolution and speciationLeaves in dry environments often have features that reduce water loss. The value of a feature depends on environmental conditions and trade-offs.https://exercises.lol/video-media/ib_biology_sl/supported-focus-05/supported-focus-05.enzh.mp4?v=1793277235-22382026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-062026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-06/supported-focus-06.thumb.jpg?v=1793277450Conservation of biodiversityA site with many individuals can still be dominated by one species. Abundance, richness and evenness 均匀度 describe different features of biodiversity.https://exercises.lol/video-media/ib_biology_sl/supported-focus-06/supported-focus-06.enzh.mp4?v=1793277450-22252026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-072026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-07/supported-focus-07.thumb.jpg?v=1793277716Carbohydrates and lipidsStarch, a triglyceride and a protein can all contain carbon, hydrogen and oxygen, yet their structures and functions differ. An element list alone does not…https://exercises.lol/video-media/ib_biology_sl/supported-focus-07/supported-focus-07.enzh.mp4?v=1793277716-22722026-10-29yes https://exercises.lol/videos/ib_biology_sl/supported-focus-092026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-09/supported-focus-09.thumb.jpg?v=1793277922Membranes and membrane transportA potato cylinder gains mass in one solution and loses mass in another. Its mass change provides evidence about movement of water, rather than movement of…https://exercises.lol/video-media/ib_biology_sl/supported-focus-09/supported-focus-09.enzh.mp4?v=1793277922-22532026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-112026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-11/supported-focus-11.thumb.jpg?v=1793278172Cell specializationA root-hair cell and a red blood cell have different shapes because their functions impose different demands.https://exercises.lol/video-media/ib_biology_sl/supported-focus-11/supported-focus-11.enzh.mp4?v=1793278172-22242026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-122026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-12/supported-focus-12.thumb.jpg?v=1793247574Gas exchangeAn exchange surface can be very thin yet fail to deliver enough oxygen when ventilation 通气 or blood flow falls.https://exercises.lol/video-media/ib_biology_sl/supported-focus-12/supported-focus-12.enzh.mp4?v=1793247574-22392026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-132026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-13/supported-focus-13.thumb.jpg?v=1793278742TransportTwo foods can have the same mass but provide different nutrients. A health claim must distinguish the nutrient measured from the health outcome inferred.https://exercises.lol/video-media/ib_biology_sl/supported-focus-13/supported-focus-13.enzh.mp4?v=1793278742-22312026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-152026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-15/supported-focus-15.thumb.jpg?v=1793278358Ecological nichesTwo species can share a habitat while using different resources or using the same resource at different times. A niche describes more than a location.https://exercises.lol/video-media/ib_biology_sl/supported-focus-15/supported-focus-15.enzh.mp4?v=1793278358-22692026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-162026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-16/supported-focus-16.thumb.jpg?v=1793278575Enzymes and metabolismAn enzyme 酶 works quickly at one temperature and slowly at another. Heating can increase successful collisions, but excessive heat can change the active site.https://exercises.lol/video-media/ib_biology_sl/supported-focus-16/supported-focus-16.enzh.mp4?v=1793278575-22342026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-172026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-17/supported-focus-17.thumb.jpg?v=1793278931Cell respirationA muscle can use oxygen while you exercise without producing a flame. Respiration 呼吸作用 transfers energy through a controlled series of reactions.https://exercises.lol/video-media/ib_biology_sl/supported-focus-17/supported-focus-17.enzh.mp4?v=1793278931-22732026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-182026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-18/supported-focus-18.thumb.jpg?v=1793279089PhotosynthesisA brighter lamp does not always produce more oxygen from pondweed. Another factor may limit the process when light is already sufficient.https://exercises.lol/video-media/ib_biology_sl/supported-focus-18/supported-focus-18.enzh.mp4?v=1793279089-22312026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-192026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-19/supported-focus-19.thumb.jpg?v=1793279234Neural signallingA stronger stimulus can increase impulse frequency while each action potential 动作电位 remains a similar size.https://exercises.lol/video-media/ib_biology_sl/supported-focus-19/supported-focus-19.enzh.mp4?v=1793279234-22312026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-202026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-20/supported-focus-20.thumb.jpg?v=1793247983Integration of body systemsBlood glucose rises after a meal, but usually does not keep rising indefinitely. A control system responds to the change in internal conditions.https://exercises.lol/video-media/ib_biology_sl/supported-focus-20/supported-focus-20.enzh.mp4?v=1793247983-22382026-10-29yes https://exercises.lol/videos/ib_biology_sl/supported-focus-212026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-21/supported-focus-21.thumb.jpg?v=1793279516Defence against diseaseAn antibiotic may help against a bacterial infection but fail against a viral illness. Treatment depends on the causal organism and the evidence supporting…https://exercises.lol/video-media/ib_biology_sl/supported-focus-21/supported-focus-21.enzh.mp4?v=1793279516-22272026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-222026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-22/supported-focus-22.thumb.jpg?v=1793279449Populations and communitiesA field edge looks richer in plants than its centre. Choosing only the richest patches would build the desired result into the sampling method.https://exercises.lol/video-media/ib_biology_sl/supported-focus-22/supported-focus-22.enzh.mp4?v=1793279449-22352026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-232026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-23/supported-focus-23.thumb.jpg?v=1793279789Transfer of energy and matterEnergy available as new biomass usually decreases along a food chain. Energy is conserved overall, but some transferred energy leaves the next-level production…https://exercises.lol/video-media/ib_biology_sl/supported-focus-23/supported-focus-23.enzh.mp4?v=1793279789-22842026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-242026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-24/supported-focus-24.thumb.jpg?v=1793248226DNA replicationAfter DNA replication, each daughter double helix contains one pre-existing strand and one newly synthesized strand. Copying a molecule is different from…https://exercises.lol/video-media/ib_biology_sl/supported-focus-24/supported-focus-24.enzh.mp4?v=1793248226-22792026-10-29yes https://exercises.lol/videos/ib_biology_sl/supported-focus-272026-10-28https://exercises.lol/video-media/ib_biology_sl/supported-focus-27/supported-focus-27.thumb.jpg?v=1793202302Cell and nuclear divisionA root-tip image contains cells at different stages of mitosis. A snapshot can estimate the fraction of cells dividing, but it does not time one observed cell…https://exercises.lol/video-media/ib_biology_sl/supported-focus-27/supported-focus-27.enzh.mp4?v=1793202302-22312026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-282026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-28/supported-focus-28.thumb.jpg?v=1793279901Water potentialPlant tissue can gain or lose mass in different solutions. The direction of net water movement depends on the water-potential 水势 difference, not on whether…https://exercises.lol/video-media/ib_biology_sl/supported-focus-28/supported-focus-28.enzh.mp4?v=1793279901-22712026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-292026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-29/supported-focus-29.thumb.jpg?v=1793280018ReproductionGametes normally contain one set of chromosomes, while fertilization 受精 joins two sets. Maintaining chromosome number across generations requires both…https://exercises.lol/video-media/ib_biology_sl/supported-focus-29/supported-focus-29.enzh.mp4?v=1793280018-22802026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-302026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-30/supported-focus-30.thumb.jpg?v=1793280282InheritanceTwo parents can carry a recessive allele 等位基因 without expressing the associated phenotype. Their children do not have to match the parents phenotypically.https://exercises.lol/video-media/ib_biology_sl/supported-focus-30/supported-focus-30.enzh.mp4?v=1793280282-22342026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-342026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-34/supported-focus-34.thumb.jpg?v=1793280223Climate changeOne cold day does not disprove a warming climate. Weather describes short-term conditions; climate describes distributions over longer times and regions.https://exercises.lol/video-media/ib_biology_sl/supported-focus-34/supported-focus-34.enzh.mp4?v=1793280223-22482026-10-28yes https://exercises.lol/videos/ib_biology_sl/supported-focus-352026-10-29https://exercises.lol/video-media/ib_biology_sl/supported-focus-35/supported-focus-35.thumb.jpg?v=1793280364Experimental programmeA line passing near every data point is useful, but its gradient can still be uncertain. A graph is evidence for a model within the measurement range.https://exercises.lol/video-media/ib_biology_sl/supported-focus-35/supported-focus-35.enzh.mp4?v=1793280364-22462026-10-28yes https://exercises.lol/videos/ib_business_management_hl/topic-012026-10-29https://exercises.lol/video-media/ib_business_management_hl/topic-01/topic-01.thumb.jpg?v=1793280626Introduction to business managementIn 1995 Wang Chuanfu started BYD in Shenzhen with about twenty workers, making batteries for mobile phones. It grew by building more factories, then by buying…https://exercises.lol/video-media/ib_business_management_hl/topic-01/topic-01.enzh.mp4?v=1793280626-23522026-10-28yes https://exercises.lol/videos/ib_business_management_hl/topic-022026-10-30https://exercises.lol/video-media/ib_business_management_hl/topic-02/topic-02.thumb.jpg?v=1793353125Human resource managementHaidilao's waiters are famous for friendly service, and the company gives them real power. A waiter can give a free dish or a discount without asking a…https://exercises.lol/video-media/ib_business_management_hl/topic-02/topic-02.enzh.mp4?v=1793353125-25732026-10-27yes https://exercises.lol/videos/ib_business_management_hl/topic-032026-10-30https://exercises.lol/video-media/ib_business_management_hl/topic-03/topic-03.thumb.jpg?v=1793395731Finance and accountsIn 2017 the bike-sharing company ofo had millions of yellow bikes in Chinese cities and had raised billions of dollars from investors. By the end of 2018 it…https://exercises.lol/video-media/ib_business_management_hl/topic-03/topic-03.enzh.mp4?v=1793395731-24752026-10-28yes https://exercises.lol/videos/ib_business_management_hl/topic-042026-10-30https://exercises.lol/video-media/ib_business_management_hl/topic-04/topic-04.thumb.jpg?v=1793396580MarketingLuckin Coffee opened its first shop in Beijing in 2017. Within two years it had more shops in China than Starbucks. It did not win with better coffee alone. It…https://exercises.lol/video-media/ib_business_management_hl/topic-04/topic-04.enzh.mp4?v=1793396580-24222026-10-28yes https://exercises.lol/videos/ib_business_management_hl/topic-052026-10-30https://exercises.lol/video-media/ib_business_management_hl/topic-05/topic-05.thumb.jpg?v=1793393151Operations managementIn March twenty eleven an earthquake and tsunami hit north-east Japan. Many of Toyota's suppliers stopped work. Toyota held very little stock, so within days…https://exercises.lol/video-media/ib_business_management_hl/topic-05/topic-05.enzh.mp4?v=1793393151-24472026-10-27yes https://exercises.lol/videos/ib_business_management_hl/topic-062026-11-08https://exercises.lol/video-media/ib_business_management_hl/topic-06/topic-06.thumb.jpg?v=1794114495The HL toolkit and social-enterprise action planningWhy it matters. In 1976 an economics professor called Muhammad Yunus walked into Jobra, a village near his university in Bangladesh. He met women who made…https://exercises.lol/video-media/ib_business_management_hl/topic-06/topic-06.enzh.mp4?v=1794114495-210542026-10-27yes https://exercises.lol/videos/ib_business_management_sl/topic-012026-11-08https://exercises.lol/video-media/ib_business_management_sl/topic-01/topic-01.thumb.jpg?v=1794115245Introduction to business managementWhy it matters. In February 1995 a young chemist called Wang Chuanfu borrowed 2.5 million yuan from a cousin and started a small company in Shenzhen with about…https://exercises.lol/video-media/ib_business_management_sl/topic-01/topic-01.enzh.mp4?v=1794115245-28852026-10-27yes https://exercises.lol/videos/ib_business_management_sl/topic-022026-11-08https://exercises.lol/video-media/ib_business_management_sl/topic-02/topic-02.thumb.jpg?v=1794114884Human resource managementWhy it matters. In 1994 Zhang Yong opened a hotpot restaurant with four tables in Jianyang, a small city in Sichuan. He had no experience of cooking, so he…https://exercises.lol/video-media/ib_business_management_sl/topic-02/topic-02.enzh.mp4?v=1794114884-28322026-10-27yes https://exercises.lol/videos/ib_business_management_sl/topic-032026-10-30https://exercises.lol/video-media/ib_business_management_sl/topic-03/topic-03.thumb.jpg?v=1793396556Finance and accountsIn 2017 the bike-sharing company ofo had millions of yellow bikes in Chinese cities and had raised billions of dollars from investors. By the end of 2018 it…https://exercises.lol/video-media/ib_business_management_sl/topic-03/topic-03.enzh.mp4?v=1793396556-23472026-10-28yes https://exercises.lol/videos/ib_business_management_sl/topic-042026-10-30https://exercises.lol/video-media/ib_business_management_sl/topic-04/topic-04.thumb.jpg?v=1793393318MarketingLuckin Coffee opened its first shop in Beijing in 2017. Within two years it had more shops in China than Starbucks. It did not win with better coffee alone. It…https://exercises.lol/video-media/ib_business_management_sl/topic-04/topic-04.enzh.mp4?v=1793393318-23462026-10-27yes https://exercises.lol/videos/ib_business_management_sl/topic-052026-10-30https://exercises.lol/video-media/ib_business_management_sl/topic-05/topic-05.thumb.jpg?v=1793393279Operations managementIn March twenty eleven an earthquake and tsunami hit north-east Japan. Many of Toyota's suppliers stopped work. Toyota held very little stock, so within days…https://exercises.lol/video-media/ib_business_management_sl/topic-05/topic-05.enzh.mp4?v=1793393279-22472026-10-27yes https://exercises.lol/videos/ib_cas/topic-012026-10-30https://exercises.lol/video-media/ib_cas/topic-01/topic-01.thumb.jpg?v=1793397420Creativity, activity, serviceCAS is part of the Diploma core. It is not graded, but you must complete it. For at least eighteen months you take part in experiences in three strands…https://exercises.lol/video-media/ib_cas/topic-01/topic-01.enzh.mp4?v=1793397420-21802026-10-28yes https://exercises.lol/videos/ib_chemistry_hl/supported-focus-012026-10-29https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-01/supported-focus-01.thumb.jpg?v=1793282854Introduction to the particulate nature of matterA sealed gas container changes pressure when heated. Celsius ratios cannot predict the pressure change because the gas model uses absolute temperature 绝对温度.https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-01/supported-focus-01.enzh.mp4?v=1793282854-22402026-10-28yes https://exercises.lol/videos/ib_chemistry_hl/supported-focus-022026-10-29https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-02/supported-focus-02.thumb.jpg?v=1793282430The nuclear atomA salt crystal conducts when dissolved but not when solid. The ions exist in both states; their ability to move changes.https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-02/supported-focus-02.enzh.mp4?v=1793282430-22302026-10-28yes https://exercises.lol/videos/ib_chemistry_hl/supported-focus-042026-10-29https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-04/supported-focus-04.thumb.jpg?v=1793282469Counting particles by mass: the moleThe smallest mass of reactant is not necessarily the limiting reagent 限量试剂. The balanced equation compares particle amounts, not grams directly.https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-04/supported-focus-04.enzh.mp4?v=1793282469-22402026-10-29yes https://exercises.lol/videos/ib_chemistry_hl/supported-focus-112026-10-29https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-11/supported-focus-11.thumb.jpg?v=1793282630Functional groups: classification of organic compoundsTwo compounds can have the same molecular formula but different structures. Their functional groups 官能团 help predict which reactions they undergo.https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-11/supported-focus-11.enzh.mp4?v=1793282630-22292026-10-29yes https://exercises.lol/videos/ib_chemistry_hl/supported-focus-122026-10-29https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-12/supported-focus-12.thumb.jpg?v=1793283074Measuring enthalpy changeA cup warms when two solutions react. The temperature rise measures energy transferred to the surroundings; it does not directly equal the enthalpy change 焓变.https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-12/supported-focus-12.enzh.mp4?v=1793283074-22452026-10-29yes https://exercises.lol/videos/ib_chemistry_hl/supported-focus-142026-10-29https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-14/supported-focus-14.thumb.jpg?v=1793283083Energy from fuelsA reusable container can require more energy to manufacture than a single-use one. Its impact depends on how often it is used and what happens at disposal.https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-14/supported-focus-14.enzh.mp4?v=1793283083-22472026-10-29yes https://exercises.lol/videos/ib_chemistry_hl/supported-focus-152026-10-29https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-15/supported-focus-15.thumb.jpg?v=1793282942Entropy and spontaneityA reaction can be endothermic and still be thermodynamically favourable. Enthalpy alone does not determine the direction favoured at a given temperature.https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-15/supported-focus-15.enzh.mp4?v=1793282942-22752026-10-28yes https://exercises.lol/videos/ib_chemistry_hl/supported-focus-162026-10-29https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-16/supported-focus-16.thumb.jpg?v=1793283612How much? The amount of chemical changeA burette reading is not the delivered volume. The titre 滴定体积 is the difference between final and initial readings, and both readings have uncertainty.https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-16/supported-focus-16.enzh.mp4?v=1793283612-22702026-10-28yes https://exercises.lol/videos/ib_chemistry_hl/supported-focus-172026-10-29https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-17/supported-focus-17.thumb.jpg?v=1793283578How fast? The rate of chemical changeA faster reaction finishes sooner, but it need not make more product. Rate 速率 and final yield answer different questions.https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-17/supported-focus-17.enzh.mp4?v=1793283578-22262026-10-28yes https://exercises.lol/videos/ib_chemistry_hl/supported-focus-182026-10-29https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-18/supported-focus-18.thumb.jpg?v=1793283569How far? The extent of chemical changeA reversible reaction 可逆反应 can continue in a closed vessel while measured concentrations stay constant. Constant composition does not mean particles have…https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-18/supported-focus-18.enzh.mp4?v=1793283569-22302026-10-28yes https://exercises.lol/videos/ib_chemistry_hl/supported-focus-202026-10-29https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-20/supported-focus-20.thumb.jpg?v=1793283949Electron transfer reactionsAn aqueous salt solution can produce different electrode products from the molten salt. Water introduces competing species into the system.https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-20/supported-focus-20.enzh.mp4?v=1793283949-22182026-10-28yes https://exercises.lol/videos/ib_chemistry_hl/supported-focus-232026-10-29https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-23/supported-focus-23.thumb.jpg?v=1793283993Experimental programmeA line passing near every data point is useful, but its gradient can still be uncertain. A graph is evidence for a model within the measurement range.https://exercises.lol/video-media/ib_chemistry_hl/supported-focus-23/supported-focus-23.enzh.mp4?v=1793283993-22482026-10-28yes https://exercises.lol/videos/ib_chemistry_sl/supported-focus-012026-10-29https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-01/supported-focus-01.thumb.jpg?v=1793283927Introduction to the particulate nature of matterA sealed gas container changes pressure when heated. Celsius ratios cannot predict the pressure change because the gas model uses absolute temperature 绝对温度.https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-01/supported-focus-01.enzh.mp4?v=1793283927-22402026-10-28yes https://exercises.lol/videos/ib_chemistry_sl/supported-focus-022026-10-29https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-02/supported-focus-02.thumb.jpg?v=1793284226The nuclear atomA salt crystal conducts when dissolved but not when solid. The ions exist in both states; their ability to move changes.https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-02/supported-focus-02.enzh.mp4?v=1793284226-22302026-10-28yes https://exercises.lol/videos/ib_chemistry_sl/supported-focus-042026-10-29https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-04/supported-focus-04.thumb.jpg?v=1793284100Counting particles by mass: the moleThe smallest mass of reactant is not necessarily the limiting reagent 限量试剂. The balanced equation compares particle amounts, not grams directly.https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-04/supported-focus-04.enzh.mp4?v=1793284100-22412026-10-28yes https://exercises.lol/videos/ib_chemistry_sl/supported-focus-112026-10-29https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-11/supported-focus-11.thumb.jpg?v=1793284191Functional groups: classification of organic compoundsTwo compounds can have the same molecular formula but different structures. Their functional groups 官能团 help predict which reactions they undergo.https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-11/supported-focus-11.enzh.mp4?v=1793284191-22282026-10-28yes https://exercises.lol/videos/ib_chemistry_sl/supported-focus-122026-10-29https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-12/supported-focus-12.thumb.jpg?v=1793284466Measuring enthalpy changeA cup warms when two solutions react. The temperature rise measures energy transferred to the surroundings; it does not directly equal the enthalpy change 焓变.https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-12/supported-focus-12.enzh.mp4?v=1793284466-22472026-10-29yes https://exercises.lol/videos/ib_chemistry_sl/supported-focus-142026-10-29https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-14/supported-focus-14.thumb.jpg?v=1793284462Energy from fuelsA reusable container can require more energy to manufacture than a single-use one. Its impact depends on how often it is used and what happens at disposal.https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-14/supported-focus-14.enzh.mp4?v=1793284462-22482026-10-29yes https://exercises.lol/videos/ib_chemistry_sl/supported-focus-152026-10-29https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-15/supported-focus-15.thumb.jpg?v=1793284481How much? The amount of chemical changeA burette reading is not the delivered volume. The titre 滴定体积 is the difference between final and initial readings, and both readings have uncertainty.https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-15/supported-focus-15.enzh.mp4?v=1793284481-22712026-10-29yes https://exercises.lol/videos/ib_chemistry_sl/supported-focus-162026-10-29https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-16/supported-focus-16.thumb.jpg?v=1793284576How fast? The rate of chemical changeA faster reaction finishes sooner, but it need not make more product. Rate 速率 and final yield answer different questions.https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-16/supported-focus-16.enzh.mp4?v=1793284576-22262026-10-29yes https://exercises.lol/videos/ib_chemistry_sl/supported-focus-172026-10-29https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-17/supported-focus-17.thumb.jpg?v=1793284883How far? The extent of chemical changeA reversible reaction 可逆反应 can continue in a closed vessel while measured concentrations stay constant. Constant composition does not mean particles have…https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-17/supported-focus-17.enzh.mp4?v=1793284883-22292026-10-29yes https://exercises.lol/videos/ib_chemistry_sl/supported-focus-192026-10-29https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-19/supported-focus-19.thumb.jpg?v=1793285012Electron transfer reactionsAn aqueous salt solution can produce different electrode products from the molten salt. Water introduces competing species into the system.https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-19/supported-focus-19.enzh.mp4?v=1793285012-22162026-10-29yes https://exercises.lol/videos/ib_chemistry_sl/supported-focus-222026-10-29https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-22/supported-focus-22.thumb.jpg?v=1793285098Experimental programmeA line passing near every data point is useful, but its gradient can still be uncertain. A graph is evidence for a model within the measurement range.https://exercises.lol/video-media/ib_chemistry_sl/supported-focus-22/supported-focus-22.enzh.mp4?v=1793285098-22472026-10-29yes https://exercises.lol/videos/ib_classical_languages_hl/session4-012026-10-30https://exercises.lol/video-media/ib_classical_languages_hl/session4-01/session4-01.thumb.jpg?v=1793396832Supported focus — Latin morphology and translationLatin case shows a noun's role. With these first-declension forms, -a is nominative singular and -am accusative singular. Use the supplied vocabulary: puella…https://exercises.lol/video-media/ib_classical_languages_hl/session4-01/session4-01.enzh.mp4?v=1793396832-22512026-10-29yes https://exercises.lol/videos/ib_classical_languages_hl/session4-022026-10-30https://exercises.lol/video-media/ib_classical_languages_hl/session4-02/session4-02.thumb.jpg?v=1793397184Supported focus — Latin close reading and literary effectDiction and syntax contribute to meaning together. “Semper laborat, semper sperat” means “always works, always hopes”. Repeated semper at both clause openings…https://exercises.lol/video-media/ib_classical_languages_hl/session4-02/session4-02.enzh.mp4?v=1793397184-22272026-10-29yes https://exercises.lol/videos/ib_classical_languages_hl/session4-032026-10-29https://exercises.lol/video-media/ib_classical_languages_hl/session4-03/session4-03.thumb.jpg?v=1793285731Supported focus — Classical sources and research dossierA focused inquiry asks a bounded question that actual evidence can answer. “How does this household's memorial present generosity?” is more manageable than…https://exercises.lol/video-media/ib_classical_languages_hl/session4-03/session4-03.enzh.mp4?v=1793285731-23742026-10-29yes https://exercises.lol/videos/ib_classical_languages_hl/session4-042026-10-29https://exercises.lol/video-media/ib_classical_languages_hl/session4-04/session4-04.thumb.jpg?v=1793285738Supported focus — Latin composition with rationaleFor a short original encouragement to a friend, choose simple Latin whose forms you can explain. Vocabulary: amicus = friend; amice = friend (direct address)…https://exercises.lol/video-media/ib_classical_languages_hl/session4-04/session4-04.enzh.mp4?v=1793285738-22422026-10-29yes https://exercises.lol/videos/ib_classical_languages_sl/session4-012026-10-30https://exercises.lol/video-media/ib_classical_languages_sl/session4-01/session4-01.thumb.jpg?v=1793397189Supported focus — Latin morphology and translationLatin case shows a noun's role. With these first-declension forms, -a is nominative singular and -am accusative singular. Use the supplied vocabulary: puella…https://exercises.lol/video-media/ib_classical_languages_sl/session4-01/session4-01.enzh.mp4?v=1793397189-22512026-10-29yes https://exercises.lol/videos/ib_classical_languages_sl/session4-022026-10-30https://exercises.lol/video-media/ib_classical_languages_sl/session4-02/session4-02.thumb.jpg?v=1793397443Supported focus — Latin close reading and literary effectDiction and syntax contribute to meaning together. “Semper laborat, semper sperat” means “always works, always hopes”. Repeated semper at both clause openings…https://exercises.lol/video-media/ib_classical_languages_sl/session4-02/session4-02.enzh.mp4?v=1793397443-22272026-10-29yes https://exercises.lol/videos/ib_classical_languages_sl/session4-032026-10-29https://exercises.lol/video-media/ib_classical_languages_sl/session4-03/session4-03.thumb.jpg?v=1793286251Supported focus — Classical sources and research dossierA focused inquiry asks a bounded question that actual evidence can answer. “How does this household's memorial present generosity?” is more manageable than…https://exercises.lol/video-media/ib_classical_languages_sl/session4-03/session4-03.enzh.mp4?v=1793286251-23742026-10-29yes https://exercises.lol/videos/ib_computer_science_hl/topic-012026-10-30https://exercises.lol/video-media/ib_computer_science_hl/topic-01/topic-01.thumb.jpg?v=1793401023Computer fundamentalsYou tap a photo app. Within a second its code is copied from storage into memory, the processor runs millions of instructions, the graphics chip draws the…https://exercises.lol/video-media/ib_computer_science_hl/topic-01/topic-01.enzh.mp4?v=1793401023-24212026-10-30yes https://exercises.lol/videos/ib_computer_science_hl/topic-022026-10-30https://exercises.lol/video-media/ib_computer_science_hl/topic-02/topic-02.thumb.jpg?v=1793402431NetworksYou type a web address on your phone at school. In under a second your request crosses the school Wi-Fi, a router, your internet provider and several…https://exercises.lol/video-media/ib_computer_science_hl/topic-02/topic-02.enzh.mp4?v=1793402431-23972026-10-30yes https://exercises.lol/videos/ib_computer_science_hl/topic-032026-10-30https://exercises.lol/video-media/ib_computer_science_hl/topic-03/topic-03.thumb.jpg?v=1793402185DatabasesA school library keeps loans in one spreadsheet. Each row has the student's name, form, the book and the date. When a student changes form, dozens of rows must…https://exercises.lol/video-media/ib_computer_science_hl/topic-03/topic-03.enzh.mp4?v=1793402185-23042026-10-30yes https://exercises.lol/videos/ib_computer_science_hl/topic-042026-10-30https://exercises.lol/video-media/ib_computer_science_hl/topic-04/topic-04.thumb.jpg?v=1793400348Machine learningA spam filter is not given a list of rules. Instead it is shown thousands of e-mails labelled spam or not spam, and finds the patterns itself. When spammers…https://exercises.lol/video-media/ib_computer_science_hl/topic-04/topic-04.enzh.mp4?v=1793400348-23252026-10-30yes https://exercises.lol/videos/ib_computer_science_hl/topic-052026-10-30https://exercises.lol/video-media/ib_computer_science_hl/topic-05/topic-05.thumb.jpg?v=1793400340Computational thinkingYour school wants a canteen app. Students order lunch on a phone, pay from a card balance, and the kitchen sees the orders. Nobody can write that in one go.…https://exercises.lol/video-media/ib_computer_science_hl/topic-05/topic-05.enzh.mp4?v=1793400340-22882026-10-30yes https://exercises.lol/videos/ib_computer_science_hl/topic-072026-10-30https://exercises.lol/video-media/ib_computer_science_hl/topic-07/topic-07.thumb.jpg?v=1793400468Object-oriented programmingA school app tracks thousands of students. Each has a name, a year group and grades, and each can enrol on a course or receive a grade. Separate variables for…https://exercises.lol/video-media/ib_computer_science_hl/topic-07/topic-07.enzh.mp4?v=1793400468-23242026-10-30yes https://exercises.lol/videos/ib_computer_science_hl/topic-082026-10-30https://exercises.lol/video-media/ib_computer_science_hl/topic-08/topic-08.thumb.jpg?v=1793400324Abstract data typesA music app holds a playlist of ten thousand songs. Adding a song in the middle of an array means shifting thousands of items along. Searching an unsorted list…https://exercises.lol/video-media/ib_computer_science_hl/topic-08/topic-08.enzh.mp4?v=1793400324-22682026-10-30yes https://exercises.lol/videos/ib_computer_science_hl/topic-092026-10-30https://exercises.lol/video-media/ib_computer_science_hl/topic-09/topic-09.thumb.jpg?v=1793401770Case studyEach year the IB publishes a case study some months before the examinations, and some questions are based on it. Your teacher will give you the current case.…https://exercises.lol/video-media/ib_computer_science_hl/topic-09/topic-09.enzh.mp4?v=1793401770-22602026-10-30yes https://exercises.lol/videos/ib_computer_science_sl/topic-012026-10-30https://exercises.lol/video-media/ib_computer_science_sl/topic-01/topic-01.thumb.jpg?v=1793400325Computer fundamentalsYou tap a photo app. Within a second its code is copied from storage into memory, the processor runs millions of instructions, the graphics chip draws the…https://exercises.lol/video-media/ib_computer_science_sl/topic-01/topic-01.enzh.mp4?v=1793400325-23982026-10-30yes https://exercises.lol/videos/ib_computer_science_sl/topic-022026-10-30https://exercises.lol/video-media/ib_computer_science_sl/topic-02/topic-02.thumb.jpg?v=1793400694NetworksYou type a web address on your phone at school. In under a second your request crosses the school Wi-Fi, a router, your internet provider and several…https://exercises.lol/video-media/ib_computer_science_sl/topic-02/topic-02.enzh.mp4?v=1793400694-23972026-10-30yes https://exercises.lol/videos/ib_computer_science_sl/topic-032026-10-30https://exercises.lol/video-media/ib_computer_science_sl/topic-03/topic-03.thumb.jpg?v=1793400162DatabasesA school library keeps loans in one spreadsheet. Each row has the student's name, form, the book and the date. When a student changes form, dozens of rows must…https://exercises.lol/video-media/ib_computer_science_sl/topic-03/topic-03.enzh.mp4?v=1793400162-22622026-10-30yes https://exercises.lol/videos/ib_computer_science_sl/topic-042026-10-30https://exercises.lol/video-media/ib_computer_science_sl/topic-04/topic-04.thumb.jpg?v=1793399937Machine learningA spam filter is not given a list of rules. Instead it is shown thousands of e-mails labelled spam or not spam, and finds the patterns itself. When spammers…https://exercises.lol/video-media/ib_computer_science_sl/topic-04/topic-04.enzh.mp4?v=1793399937-21832026-10-30yes https://exercises.lol/videos/ib_computer_science_sl/topic-052026-10-30https://exercises.lol/video-media/ib_computer_science_sl/topic-05/topic-05.thumb.jpg?v=1793400393Computational thinkingYour school wants a canteen app. Students order lunch on a phone, pay from a card balance, and the kitchen sees the orders. Nobody can write that in one go.…https://exercises.lol/video-media/ib_computer_science_sl/topic-05/topic-05.enzh.mp4?v=1793400393-22882026-10-30yes https://exercises.lol/videos/ib_computer_science_sl/topic-072026-10-30https://exercises.lol/video-media/ib_computer_science_sl/topic-07/topic-07.thumb.jpg?v=1793400542Object-oriented programmingA school app tracks thousands of students. Each has a name, a year group and grades, and each can enrol on a course or receive a grade. Separate variables for…https://exercises.lol/video-media/ib_computer_science_sl/topic-07/topic-07.enzh.mp4?v=1793400542-22252026-10-30yes https://exercises.lol/videos/ib_computer_science_sl/topic-082026-10-30https://exercises.lol/video-media/ib_computer_science_sl/topic-08/topic-08.thumb.jpg?v=1793400552Case studyEach year the IB publishes a case study some months before the examinations, and some questions are based on it. Your teacher will give you the current case.…https://exercises.lol/video-media/ib_computer_science_sl/topic-08/topic-08.enzh.mp4?v=1793400552-22602026-10-30yes https://exercises.lol/videos/ib_dance_hl/topic-012026-11-08https://exercises.lol/video-media/ib_dance_hl/topic-01/topic-01.thumb.jpg?v=1794126335Composition and choreographyWhy it matters. In 1971 the American choreographer Trisha Brown made a dance called Accumulation. She stood still and made one simple gesture: a rotation of…https://exercises.lol/video-media/ib_dance_hl/topic-01/topic-01.enzh.mp4?v=1794126335-24602026-10-29yes https://exercises.lol/videos/ib_dance_hl/topic-022026-11-08https://exercises.lol/video-media/ib_dance_hl/topic-02/topic-02.thumb.jpg?v=1794126216World dance studiesWhy it matters. When Christian missionaries arrived in Hawai'i in the 1820s, they saw hula as immoral, and within a few years public performances were…https://exercises.lol/video-media/ib_dance_hl/topic-02/topic-02.enzh.mp4?v=1794126216-25052026-10-29yes https://exercises.lol/videos/ib_dance_hl/topic-032026-11-08https://exercises.lol/video-media/ib_dance_hl/topic-03/topic-03.thumb.jpg?v=1794126190PerformanceWhy it matters. In 1905 the choreographer Michel Fokine made a short solo for the Russian ballerina Anna Pavlova, set to Saint-Saëns's "The Swan". It lasts…https://exercises.lol/video-media/ib_dance_hl/topic-03/topic-03.enzh.mp4?v=1794126190-24282026-10-29yes https://exercises.lol/videos/ib_dance_hl/topic-042026-11-08https://exercises.lol/video-media/ib_dance_hl/topic-04/topic-04.thumb.jpg?v=1794126649HL depth: sustained inquiryWhy it matters. In 1986 the Bai dancer Yang Liping, from Yunnan, performed a solo called Spirit of the Peacock at a national dance competition in China.…https://exercises.lol/video-media/ib_dance_hl/topic-04/topic-04.enzh.mp4?v=1794126649-24022026-10-29yes https://exercises.lol/videos/ib_dance_sl/topic-012026-11-08https://exercises.lol/video-media/ib_dance_sl/topic-01/topic-01.thumb.jpg?v=1794126659Composition and choreographyWhy it matters. In 1971 the American choreographer Trisha Brown made a dance called Accumulation. She stood still and made one simple gesture: a rotation of…https://exercises.lol/video-media/ib_dance_sl/topic-01/topic-01.enzh.mp4?v=1794126659-24552026-10-29yes https://exercises.lol/videos/ib_dance_sl/topic-022026-11-08https://exercises.lol/video-media/ib_dance_sl/topic-02/topic-02.thumb.jpg?v=1794126677World dance studiesWhy it matters. When Christian missionaries arrived in Hawai'i in the 1820s, they saw hula as immoral, and within a few years public performances were…https://exercises.lol/video-media/ib_dance_sl/topic-02/topic-02.enzh.mp4?v=1794126677-25002026-10-29yes https://exercises.lol/videos/ib_dance_sl/topic-032026-11-08https://exercises.lol/video-media/ib_dance_sl/topic-03/topic-03.thumb.jpg?v=1794127140PerformanceWhy it matters. In 1905 the choreographer Michel Fokine made a short solo for the Russian ballerina Anna Pavlova, set to Saint-Saëns's "The Swan". It lasts…https://exercises.lol/video-media/ib_dance_sl/topic-03/topic-03.enzh.mp4?v=1794127140-24192026-10-29yes https://exercises.lol/videos/ib_design_technology_hl/supported-focus-012026-10-29https://exercises.lol/video-media/ib_design_technology_hl/supported-focus-01/supported-focus-01.thumb.jpg?v=1793288205Design in theoryThese are selected topics, not the whole syllabus, and every example is fictional. Design evidence starts with the people who will use the product and turns…https://exercises.lol/video-media/ib_design_technology_hl/supported-focus-01/supported-focus-01.enzh.mp4?v=1793288205-21192026-10-29yes https://exercises.lol/videos/ib_design_technology_hl/supported-focus-022026-10-29https://exercises.lol/video-media/ib_design_technology_hl/supported-focus-02/supported-focus-02.thumb.jpg?v=1793288009Design in practiceThese are selected topics, not the whole syllabus, and every example is fictional. Every model answers one question; iteration revises a design from evidence…https://exercises.lol/video-media/ib_design_technology_hl/supported-focus-02/supported-focus-02.enzh.mp4?v=1793288009-21262026-10-29yes https://exercises.lol/videos/ib_design_technology_hl/supported-focus-032026-10-29https://exercises.lol/video-media/ib_design_technology_hl/supported-focus-03/supported-focus-03.thumb.jpg?v=1793288128Design in contextThese are selected topics, not the whole syllabus, and every example is fictional. A production choice weighs fixed and per-item costs, and a sustainability…https://exercises.lol/video-media/ib_design_technology_hl/supported-focus-03/supported-focus-03.enzh.mp4?v=1793288128-2732026-10-29yes https://exercises.lol/videos/ib_design_technology_sl/supported-focus-012026-10-29https://exercises.lol/video-media/ib_design_technology_sl/supported-focus-01/supported-focus-01.thumb.jpg?v=1793288265Design in theoryThese are selected topics, not the whole syllabus, and every example is fictional. Design evidence starts with the people who will use the product and turns…https://exercises.lol/video-media/ib_design_technology_sl/supported-focus-01/supported-focus-01.enzh.mp4?v=1793288265-21192026-10-29yes https://exercises.lol/videos/ib_design_technology_sl/supported-focus-022026-10-29https://exercises.lol/video-media/ib_design_technology_sl/supported-focus-02/supported-focus-02.thumb.jpg?v=1793288449Design in practiceThese are selected topics, not the whole syllabus, and every example is fictional. Every model answers one question; iteration revises a design from evidence…https://exercises.lol/video-media/ib_design_technology_sl/supported-focus-02/supported-focus-02.enzh.mp4?v=1793288449-21262026-10-29yes https://exercises.lol/videos/ib_design_technology_sl/supported-focus-032026-10-29https://exercises.lol/video-media/ib_design_technology_sl/supported-focus-03/supported-focus-03.thumb.jpg?v=1793288538Design in contextThese are selected topics, not the whole syllabus, and every example is fictional. A production choice weighs fixed and per-item costs, and a sustainability…https://exercises.lol/video-media/ib_design_technology_sl/supported-focus-03/supported-focus-03.enzh.mp4?v=1793288538-2732026-10-29yes https://exercises.lol/videos/ib_digital_society_hl/topic-012026-10-29https://exercises.lol/video-media/ib_digital_society_hl/topic-01/topic-01.thumb.jpg?v=1793295822Data, algorithms and digital powerIn 2020 the pandemic cancelled England's A-level exams, so a formula decided the grades. It took each school's past results and each teacher's ranking of their…https://exercises.lol/video-media/ib_digital_society_hl/topic-01/topic-01.enzh.mp4?v=1793295822-22362026-10-29yes https://exercises.lol/videos/ib_digital_society_hl/topic-022026-10-29https://exercises.lol/video-media/ib_digital_society_hl/topic-02/topic-02.thumb.jpg?v=1793289048Networks, media and automationIn March 2011 an earthquake and tsunami damaged the Fukushima nuclear station. Within days a rumour spread across China by text message and social media, that…https://exercises.lol/video-media/ib_digital_society_hl/topic-02/topic-02.enzh.mp4?v=1793289048-22162026-10-29yes https://exercises.lol/videos/ib_digital_society_hl/topic-032026-11-08https://exercises.lol/video-media/ib_digital_society_hl/topic-03/topic-03.thumb.jpg?v=1794113807The inquiry projectWhy it matters. During the COVID-19 pandemic, people in China showed a green health code on their phones to take a bus, enter a shop or visit a hospital. For…https://exercises.lol/video-media/ib_digital_society_hl/topic-03/topic-03.enzh.mp4?v=1794113807-25532026-10-27yes https://exercises.lol/videos/ib_digital_society_hl/topic-042026-10-30https://exercises.lol/video-media/ib_digital_society_hl/topic-04/topic-04.thumb.jpg?v=1793397439HL challenges and interventionsIn August 2021 China limited players under eighteen to one hour of online games, from eight to nine pm on Fridays, weekends and holidays, and game companies…https://exercises.lol/video-media/ib_digital_society_hl/topic-04/topic-04.enzh.mp4?v=1793397439-22122026-10-29yes https://exercises.lol/videos/ib_digital_society_sl/topic-012026-10-29https://exercises.lol/video-media/ib_digital_society_sl/topic-01/topic-01.thumb.jpg?v=1793289380Data, algorithms and digital powerIn 2020 the pandemic cancelled England's A-level exams, so a formula decided the grades. It took each school's past results and each teacher's ranking of their…https://exercises.lol/video-media/ib_digital_society_sl/topic-01/topic-01.enzh.mp4?v=1793289380-22362026-10-29yes https://exercises.lol/videos/ib_digital_society_sl/topic-022026-10-29https://exercises.lol/video-media/ib_digital_society_sl/topic-02/topic-02.thumb.jpg?v=1793289634Networks, media and automationIn March 2011 an earthquake and tsunami damaged the Fukushima nuclear station. Within days a rumour spread across China by text message and social media, that…https://exercises.lol/video-media/ib_digital_society_sl/topic-02/topic-02.enzh.mp4?v=1793289634-22162026-10-29yes https://exercises.lol/videos/ib_digital_society_sl/topic-032026-11-08https://exercises.lol/video-media/ib_digital_society_sl/topic-03/topic-03.thumb.jpg?v=1794113964The inquiry projectWhy it matters. During the COVID-19 pandemic, people in China showed a green health code on their phones to take a bus, enter a shop or visit a hospital. For…https://exercises.lol/video-media/ib_digital_society_sl/topic-03/topic-03.enzh.mp4?v=1794113964-25532026-10-27yes https://exercises.lol/videos/ib_economics_hl/topic-012026-11-08https://exercises.lol/video-media/ib_economics_hl/topic-01/topic-01.thumb.jpg?v=1794114417Introduction to economicsWhy it matters. In January 2018 the city of Cape Town in South Africa, home to about four million people, announced that it might soon become the first major…https://exercises.lol/video-media/ib_economics_hl/topic-01/topic-01.enzh.mp4?v=1794114417-27492026-10-27yes https://exercises.lol/videos/ib_economics_hl/topic-022026-11-08https://exercises.lol/video-media/ib_economics_hl/topic-02/topic-02.thumb.jpg?v=1794122603Demand, supply and policyWhy it matters. When the Beijing Winter Olympics opened on 4 February 2022, the official mascot, a panda in an ice shell called Bing Dwen Dwen, suddenly became…https://exercises.lol/video-media/ib_economics_hl/topic-02/topic-02.enzh.mp4?v=1794122603-212212026-10-27yes https://exercises.lol/videos/ib_economics_hl/topic-032026-11-08https://exercises.lol/video-media/ib_economics_hl/topic-03/topic-03.thumb.jpg?v=1794114930Market failure and equityWhy it matters. For almost 500 years, fishing boats from Europe and North America caught cod on the Grand Banks off Newfoundland, in Canada. The cod were so…https://exercises.lol/video-media/ib_economics_hl/topic-03/topic-03.enzh.mp4?v=1794114930-211612026-10-27yes https://exercises.lol/videos/ib_economics_hl/topic-042026-10-30https://exercises.lol/video-media/ib_economics_hl/topic-04/topic-04.thumb.jpg?v=1793393326Information and market powerIn 2021 China's market regulator fined Alibaba eighteen point two billion yuan. It had told sellers they could not also sell on rival platforms. A firm can…https://exercises.lol/video-media/ib_economics_hl/topic-04/topic-04.enzh.mp4?v=1793393326-24522026-10-27yes https://exercises.lol/videos/ib_economics_hl/topic-052026-10-30https://exercises.lol/video-media/ib_economics_hl/topic-05/topic-05.thumb.jpg?v=1793393351Macroeconomic activity, objectives and policyIn 2020 output fell faster than at any time since the 1930s, and central banks cut interest rates close to zero. Two years later inflation reached a forty-year…https://exercises.lol/video-media/ib_economics_hl/topic-05/topic-05.enzh.mp4?v=1793393351-26262026-10-27yes https://exercises.lol/videos/ib_economics_hl/topic-062026-10-30https://exercises.lol/video-media/ib_economics_hl/topic-06/topic-06.thumb.jpg?v=1793398163The global economyIn 1980 China opened its first special economic zone in Shenzhen, then a small town. Today it is a city of more than seventeen million, and China is the…https://exercises.lol/video-media/ib_economics_hl/topic-06/topic-06.enzh.mp4?v=1793398163-25232026-10-29yes https://exercises.lol/videos/ib_economics_sl/topic-012026-11-08https://exercises.lol/video-media/ib_economics_sl/topic-01/topic-01.thumb.jpg?v=1794115040Introduction to economicsWhy it matters. In January 2018 the city of Cape Town in South Africa, home to about four million people, announced that it might soon become the first major…https://exercises.lol/video-media/ib_economics_sl/topic-01/topic-01.enzh.mp4?v=1794115040-27642026-10-27yes https://exercises.lol/videos/ib_economics_sl/topic-022026-11-08https://exercises.lol/video-media/ib_economics_sl/topic-02/topic-02.thumb.jpg?v=1794111574Demand, supply and policyWhy it matters. When the Beijing Winter Olympics opened on 4 February 2022, the official mascot, a panda in an ice shell called Bing Dwen Dwen, suddenly became…https://exercises.lol/video-media/ib_economics_sl/topic-02/topic-02.enzh.mp4?v=1794111574-212272026-10-27yes https://exercises.lol/videos/ib_economics_sl/topic-032026-11-08https://exercises.lol/video-media/ib_economics_sl/topic-03/topic-03.thumb.jpg?v=1794114804Market failure and equityWhy it matters. For almost 500 years, fishing boats from Europe and North America caught cod on the Grand Banks off Newfoundland, in Canada. The cod were so…https://exercises.lol/video-media/ib_economics_sl/topic-03/topic-03.enzh.mp4?v=1794114804-211752026-10-27yes https://exercises.lol/videos/ib_economics_sl/topic-042026-10-30https://exercises.lol/video-media/ib_economics_sl/topic-04/topic-04.thumb.jpg?v=1793395521Macroeconomic activity, objectives and policyIn 2020 output fell faster than at any time since the 1930s, and central banks cut interest rates close to zero. Two years later inflation reached a forty-year…https://exercises.lol/video-media/ib_economics_sl/topic-04/topic-04.enzh.mp4?v=1793395521-24932026-10-27yes https://exercises.lol/videos/ib_economics_sl/topic-052026-10-30https://exercises.lol/video-media/ib_economics_sl/topic-05/topic-05.thumb.jpg?v=1793394930The global economyIn 1980 China opened its first special economic zone in Shenzhen, then a small town. Today it is a city of more than seventeen million, and China is the…https://exercises.lol/video-media/ib_economics_sl/topic-05/topic-05.enzh.mp4?v=1793394930-24072026-10-27yes https://exercises.lol/videos/ib_environmental_systems_hl/supported-focus-012026-10-29https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-01/supported-focus-01.thumb.jpg?v=1793290477FoundationThese are selected topics, not the whole syllabus, and every example is fictional. A system has a boundary, stocks and flows, and feedback decides how it…https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-01/supported-focus-01.enzh.mp4?v=1793290477-2672026-10-29yes https://exercises.lol/videos/ib_environmental_systems_hl/supported-focus-022026-10-29https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-02/supported-focus-02.thumb.jpg?v=1793290555EcologyThese are selected topics, not the whole syllabus, and every example is fictional. Random quadrats estimate a population without choosing the answer.https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-02/supported-focus-02.enzh.mp4?v=1793290555-2672026-10-29yes https://exercises.lol/videos/ib_environmental_systems_hl/supported-focus-032026-10-29https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-03/supported-focus-03.thumb.jpg?v=1793290619Biodiversity and conservationThese are selected topics, not the whole syllabus, and every example is fictional. Richness counts species; evenness asks how evenly the individuals are shared.https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-03/supported-focus-03.enzh.mp4?v=1793290619-2712026-10-29yes https://exercises.lol/videos/ib_environmental_systems_hl/supported-focus-042026-10-29https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-04/supported-focus-04.thumb.jpg?v=1793290677WaterThese are selected topics, not the whole syllabus, and every example is fictional. Nutrients can starve a river of oxygen, and a load is concentration times…https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-04/supported-focus-04.enzh.mp4?v=1793290677-2732026-10-29yes https://exercises.lol/videos/ib_environmental_systems_hl/supported-focus-052026-10-29https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-05/supported-focus-05.thumb.jpg?v=1793290749LandThese are selected topics, not the whole syllabus, and every example is fictional. Compare farms by yield per hectare, and remember that renewable resources…https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-05/supported-focus-05.enzh.mp4?v=1793290749-2652026-10-29yes https://exercises.lol/videos/ib_environmental_systems_hl/supported-focus-062026-10-29https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-06/supported-focus-06.thumb.jpg?v=1793290989Atmosphere and climate changeThese are selected topics, not the whole syllabus, and every example is fictional. Climate is a long-term pattern, the energy budget sets the warming, and…https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-06/supported-focus-06.enzh.mp4?v=1793290989-2882026-10-29yes https://exercises.lol/videos/ib_environmental_systems_hl/supported-focus-082026-10-29https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-08/supported-focus-08.thumb.jpg?v=1793290941Human populations and urban systemsThese are selected topics, not the whole syllabus, and every example is fictional. Population change has four flows, and an indicator measures one specified…https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-08/supported-focus-08.enzh.mp4?v=1793290941-2682026-10-29yes https://exercises.lol/videos/ib_environmental_systems_hl/supported-focus-092026-10-29https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-09/supported-focus-09.thumb.jpg?v=1793290870Environmental lawThese are selected topics, not the whole syllabus, and every example is fictional. A law changes outcomes only through coverage, implementation and enforcement.https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-09/supported-focus-09.enzh.mp4?v=1793290870-2702026-10-29yes https://exercises.lol/videos/ib_environmental_systems_hl/supported-focus-102026-10-29https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-10/supported-focus-10.thumb.jpg?v=1793290982Environmental and ecological economicsThese are selected topics, not the whole syllabus, and every example is fictional. A market price can leave out costs that fall on other people.https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-10/supported-focus-10.enzh.mp4?v=1793290982-2732026-10-29yes https://exercises.lol/videos/ib_environmental_systems_hl/supported-focus-112026-10-29https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-11/supported-focus-11.thumb.jpg?v=1793291184Environmental ethicsThese are selected topics, not the whole syllabus, and every example is fictional. Measure the change, then argue from a stated value position.https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-11/supported-focus-11.enzh.mp4?v=1793291184-2622026-10-29yes https://exercises.lol/videos/ib_environmental_systems_hl/supported-focus-122026-10-29https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-12/supported-focus-12.thumb.jpg?v=1793291031Experimental programmeThese are selected topics, not the whole syllabus, and every example is fictional. Every reading carries an uncertainty; random scatter averages out…https://exercises.lol/video-media/ib_environmental_systems_hl/supported-focus-12/supported-focus-12.enzh.mp4?v=1793291031-2632026-10-29yes https://exercises.lol/videos/ib_environmental_systems_sl/supported-focus-012026-10-29https://exercises.lol/video-media/ib_environmental_systems_sl/supported-focus-01/supported-focus-01.thumb.jpg?v=1793291232FoundationThese are selected topics, not the whole syllabus, and every example is fictional. A system has a boundary, stocks and flows, and feedback decides how it…https://exercises.lol/video-media/ib_environmental_systems_sl/supported-focus-01/supported-focus-01.enzh.mp4?v=1793291232-2672026-10-29yes https://exercises.lol/videos/ib_environmental_systems_sl/supported-focus-022026-10-29https://exercises.lol/video-media/ib_environmental_systems_sl/supported-focus-02/supported-focus-02.thumb.jpg?v=1793291083EcologyThese are selected topics, not the whole syllabus, and every example is fictional. Random quadrats estimate a population without choosing the answer.https://exercises.lol/video-media/ib_environmental_systems_sl/supported-focus-02/supported-focus-02.enzh.mp4?v=1793291083-2672026-10-29yes https://exercises.lol/videos/ib_environmental_systems_sl/supported-focus-032026-10-29https://exercises.lol/video-media/ib_environmental_systems_sl/supported-focus-03/supported-focus-03.thumb.jpg?v=1793291125Biodiversity and conservationThese are selected topics, not the whole syllabus, and every example is fictional. Richness counts species; evenness asks how evenly the individuals are shared.https://exercises.lol/video-media/ib_environmental_systems_sl/supported-focus-03/supported-focus-03.enzh.mp4?v=1793291125-2712026-10-29yes https://exercises.lol/videos/ib_environmental_systems_sl/supported-focus-042026-10-29https://exercises.lol/video-media/ib_environmental_systems_sl/supported-focus-04/supported-focus-04.thumb.jpg?v=1793311133WaterThese are selected topics, not the whole syllabus, and every example is fictional. Nutrients can starve a river of oxygen, and a load is concentration times…https://exercises.lol/video-media/ib_environmental_systems_sl/supported-focus-04/supported-focus-04.enzh.mp4?v=1793311133-2732026-10-29yes https://exercises.lol/videos/ib_environmental_systems_sl/supported-focus-052026-10-29https://exercises.lol/video-media/ib_environmental_systems_sl/supported-focus-05/supported-focus-05.thumb.jpg?v=1793291236LandThese are selected topics, not the whole syllabus, and every example is fictional. Compare farms by yield per hectare, and remember that renewable resources…https://exercises.lol/video-media/ib_environmental_systems_sl/supported-focus-05/supported-focus-05.enzh.mp4?v=1793291236-2652026-10-29yes https://exercises.lol/videos/ib_environmental_systems_sl/supported-focus-062026-10-29https://exercises.lol/video-media/ib_environmental_systems_sl/supported-focus-06/supported-focus-06.thumb.jpg?v=1793291282Atmosphere and climate changeThese are selected topics, not the whole syllabus, and every example is fictional. Climate is a long-term pattern, the energy budget sets the warming, and…https://exercises.lol/video-media/ib_environmental_systems_sl/supported-focus-06/supported-focus-06.enzh.mp4?v=1793291282-2882026-10-29yes https://exercises.lol/videos/ib_environmental_systems_sl/supported-focus-082026-10-29https://exercises.lol/video-media/ib_environmental_systems_sl/supported-focus-08/supported-focus-08.thumb.jpg?v=1793291397Human populations and urban systemsThese are selected topics, not the whole syllabus, and every example is fictional. Population change has four flows, and an indicator measures one specified…https://exercises.lol/video-media/ib_environmental_systems_sl/supported-focus-08/supported-focus-08.enzh.mp4?v=1793291397-2682026-10-29yes https://exercises.lol/videos/ib_environmental_systems_sl/supported-focus-092026-10-29https://exercises.lol/video-media/ib_environmental_systems_sl/supported-focus-09/supported-focus-09.thumb.jpg?v=1793291391Experimental programmeThese are selected topics, not the whole syllabus, and every example is fictional. Every reading carries an uncertainty; random scatter averages out…https://exercises.lol/video-media/ib_environmental_systems_sl/supported-focus-09/supported-focus-09.enzh.mp4?v=1793291391-2632026-10-29yes https://exercises.lol/videos/ib_extended_essay/topic-012026-10-30https://exercises.lol/video-media/ib_extended_essay/topic-01/topic-01.thumb.jpg?v=1793397433Research questions, evidence and academic integrityThe Extended Essay is an independent research project in one subject: an essay of up to four thousand words, about forty hours of work. A supervisor at your…https://exercises.lol/video-media/ib_extended_essay/topic-01/topic-01.enzh.mp4?v=1793397433-22122026-10-29yes https://exercises.lol/videos/ib_film_hl/topic-012026-10-30https://exercises.lol/video-media/ib_film_hl/topic-01/topic-01.thumb.jpg?v=1793329185Reading filmThe textual analysis is a written analysis of a prescribed film, based on an extract of at most 5 minutes. It is at most 1,750 words, with a list of sources…https://exercises.lol/video-media/ib_film_hl/topic-01/topic-01.enzh.mp4?v=1793329185-21492026-10-27yes https://exercises.lol/videos/ib_film_hl/topic-022026-11-08https://exercises.lol/video-media/ib_film_hl/topic-02/topic-02.thumb.jpg?v=1794114014Comparing filmsWhy it matters. In 1954 the Japanese director Akira Kurosawa released Seven Samurai: a poor farming village, tired of bandits stealing its rice, hires seven…https://exercises.lol/video-media/ib_film_hl/topic-02/topic-02.enzh.mp4?v=1794114014-24262026-10-27yes https://exercises.lol/videos/ib_film_hl/topic-032026-10-29https://exercises.lol/video-media/ib_film_hl/topic-03/topic-03.thumb.jpg?v=1793291567The film portfolioThe portfolio covers three production roles: at most 3 pages and 3 minutes of reel for each, so at most 9 minutes in all, including one completed film. It is…https://exercises.lol/video-media/ib_film_hl/topic-03/topic-03.enzh.mp4?v=1793291567-21322026-10-29yes https://exercises.lol/videos/ib_film_hl/topic-042026-11-08https://exercises.lol/video-media/ib_film_hl/topic-04/topic-04.thumb.jpg?v=1794113675The collaborative film projectWhy it matters. In 1974 the young director Steven Spielberg began filming Jaws off the island of Martha's Vineyard, on the coast of Massachusetts. The film's…https://exercises.lol/video-media/ib_film_hl/topic-04/topic-04.enzh.mp4?v=1794113675-24482026-10-27yes https://exercises.lol/videos/ib_film_sl/topic-012026-11-08https://exercises.lol/video-media/ib_film_sl/topic-01/topic-01.thumb.jpg?v=1794113912Reading filmWhy it matters. In Alfred Hitchcock's Psycho (1960), a woman is murdered in a motel shower. The scene lasts less than a minute on screen but took about a week…https://exercises.lol/video-media/ib_film_sl/topic-01/topic-01.enzh.mp4?v=1794113912-25132026-10-27yes https://exercises.lol/videos/ib_film_sl/topic-022026-10-29https://exercises.lol/video-media/ib_film_sl/topic-02/topic-02.thumb.jpg?v=1793291774Comparing filmsThe comparative study is a recorded multimedia presentation of at most 10 minutes, comparing two films from different cultural contexts on one chosen focus. It…https://exercises.lol/video-media/ib_film_sl/topic-02/topic-02.enzh.mp4?v=1793291774-21282026-10-27yes https://exercises.lol/videos/ib_film_sl/topic-032026-10-29https://exercises.lol/video-media/ib_film_sl/topic-03/topic-03.thumb.jpg?v=1793291689The film portfolioThe portfolio covers three production roles: at most 3 pages and 3 minutes of reel for each, so at most 9 minutes in all, including one completed film. It is…https://exercises.lol/video-media/ib_film_sl/topic-03/topic-03.enzh.mp4?v=1793291689-21322026-10-29yes https://exercises.lol/videos/ib_geography_hl/topic-012026-10-30https://exercises.lol/video-media/ib_geography_hl/topic-01/topic-01.thumb.jpg?v=1793393459Changing populationIn 2024, nine point five four million babies were born in China and ten point nine three million people died. The population fell for the third year in a row.…https://exercises.lol/video-media/ib_geography_hl/topic-01/topic-01.enzh.mp4?v=1793393459-24072026-10-27yes https://exercises.lol/videos/ib_geography_hl/topic-022026-10-31https://exercises.lol/video-media/ib_geography_hl/topic-02/topic-02.thumb.jpg?v=1793407625Climate and resourcesIn July 2021, a storm dropped two hundred and one point nine millimetres of rain on Zhengzhou in one hour. Streets and a subway line flooded, and almost four…https://exercises.lol/video-media/ib_geography_hl/topic-02/topic-02.enzh.mp4?v=1793407625-25302026-10-29yes https://exercises.lol/videos/ib_geography_hl/topic-032026-10-29https://exercises.lol/video-media/ib_geography_hl/topic-03/topic-03.thumb.jpg?v=1793293496Options and fieldworkBesides the core, every student studies optional themes: two at standard level, three at higher level, examined in Paper 1. Every student also writes a…https://exercises.lol/video-media/ib_geography_hl/topic-03/topic-03.enzh.mp4?v=1793293496-26162026-10-29yes https://exercises.lol/videos/ib_geography_hl/topic-042026-10-30https://exercises.lol/video-media/ib_geography_hl/topic-04/topic-04.thumb.jpg?v=1793394989Global interactionsIn March 2021 the container ship Ever Given got stuck across the Suez Canal for six days. Hundreds of ships waited at both ends, and factories in Europe ran…https://exercises.lol/video-media/ib_geography_hl/topic-04/topic-04.enzh.mp4?v=1793394989-23682026-10-27yes https://exercises.lol/videos/ib_geography_sl/topic-012026-10-30https://exercises.lol/video-media/ib_geography_sl/topic-01/topic-01.thumb.jpg?v=1793393906Changing populationIn 2024, nine point five four million babies were born in China and ten point nine three million people died. The population fell for the third year in a row.…https://exercises.lol/video-media/ib_geography_sl/topic-01/topic-01.enzh.mp4?v=1793393906-24072026-10-28yes https://exercises.lol/videos/ib_geography_sl/topic-022026-10-30https://exercises.lol/video-media/ib_geography_sl/topic-02/topic-02.thumb.jpg?v=1793397867Climate and resourcesIn July 2021, a storm dropped two hundred and one point nine millimetres of rain on Zhengzhou in one hour. Streets and a subway line flooded, and almost four…https://exercises.lol/video-media/ib_geography_sl/topic-02/topic-02.enzh.mp4?v=1793397867-25302026-10-29yes https://exercises.lol/videos/ib_geography_sl/topic-032026-10-29https://exercises.lol/video-media/ib_geography_sl/topic-03/topic-03.thumb.jpg?v=1793294775Options and fieldworkBesides the core, every student studies optional themes: two at standard level, three at higher level, examined in Paper 1. Every student also writes a…https://exercises.lol/video-media/ib_geography_sl/topic-03/topic-03.enzh.mp4?v=1793294775-26162026-10-29yes https://exercises.lol/videos/ib_global_politics_hl/topic-012026-10-30https://exercises.lol/video-media/ib_global_politics_hl/topic-01/topic-01.thumb.jpg?v=1793395926Power, sovereignty and legitimacyIn 2021 a container ship got stuck across the Suez Canal for six days, and factories in Europe ran short of parts from Asia. No government chose this, and no…https://exercises.lol/video-media/ib_global_politics_hl/topic-01/topic-01.enzh.mp4?v=1793395926-23192026-10-27yes https://exercises.lol/videos/ib_global_politics_hl/topic-022026-10-30https://exercises.lol/video-media/ib_global_politics_hl/topic-02/topic-02.thumb.jpg?v=1793402462Thematic studiesBesides the core, every student studies three themes: rights and justice, development and sustainability, and peace and conflict. Each is studied through real…https://exercises.lol/video-media/ib_global_politics_hl/topic-02/topic-02.enzh.mp4?v=1793402462-23652026-10-27yes https://exercises.lol/videos/ib_global_politics_hl/topic-032026-10-30https://exercises.lol/video-media/ib_global_politics_hl/topic-03/topic-03.thumb.jpg?v=1793402067The engagement projectEvery evening in Chinese cities, millions of food-delivery riders race the clock. An app sets their routes, their time limits and their pay. Who decided those…https://exercises.lol/video-media/ib_global_politics_hl/topic-03/topic-03.enzh.mp4?v=1793402067-22582026-10-27yes https://exercises.lol/videos/ib_global_politics_hl/topic-042026-10-30https://exercises.lol/video-media/ib_global_politics_hl/topic-04/topic-04.thumb.jpg?v=1793393895Global political challengesIn August 2022 heavy monsoon rain and melting glaciers put about one third of Pakistan under water. More than seventeen hundred people died. The floods spread…https://exercises.lol/video-media/ib_global_politics_hl/topic-04/topic-04.enzh.mp4?v=1793393895-23432026-10-27yes https://exercises.lol/videos/ib_global_politics_sl/topic-012026-10-30https://exercises.lol/video-media/ib_global_politics_sl/topic-01/topic-01.thumb.jpg?v=1793392780Power, sovereignty and legitimacyIn 2021 a container ship got stuck across the Suez Canal for six days, and factories in Europe ran short of parts from Asia. No government chose this, and no…https://exercises.lol/video-media/ib_global_politics_sl/topic-01/topic-01.enzh.mp4?v=1793392780-23192026-10-27yes https://exercises.lol/videos/ib_global_politics_sl/topic-022026-10-30https://exercises.lol/video-media/ib_global_politics_sl/topic-02/topic-02.thumb.jpg?v=1793393906Thematic studiesBesides the core, every student studies three themes: rights and justice, development and sustainability, and peace and conflict. Each is studied through real…https://exercises.lol/video-media/ib_global_politics_sl/topic-02/topic-02.enzh.mp4?v=1793393906-23652026-10-27yes https://exercises.lol/videos/ib_global_politics_sl/topic-032026-10-30https://exercises.lol/video-media/ib_global_politics_sl/topic-03/topic-03.thumb.jpg?v=1793392803The engagement projectEvery evening in Chinese cities, millions of food-delivery riders race the clock. An app sets their routes, their time limits and their pay. Who decided those…https://exercises.lol/video-media/ib_global_politics_sl/topic-03/topic-03.enzh.mp4?v=1793392803-22582026-10-27yes https://exercises.lol/videos/ib_history_hl/topic-012026-10-30https://exercises.lol/video-media/ib_history_hl/topic-01/topic-01.thumb.jpg?v=1793393798Sources and the prescribed subjectOn the twentieth of September 1939 a London newspaper printed a cartoon by David Low. Hitler and Stalin bow politely over the body of a dead soldier, Poland.…https://exercises.lol/video-media/ib_history_hl/topic-01/topic-01.enzh.mp4?v=1793393798-23542026-10-27yes https://exercises.lol/videos/ib_history_hl/topic-022026-10-30https://exercises.lol/video-media/ib_history_hl/topic-02/topic-02.thumb.jpg?v=1793393888World history topicsIn May 1928 the Nazi Party won twelve of four hundred and ninety-one seats in the German parliament. Four and a half years later, its leader was head of the…https://exercises.lol/video-media/ib_history_hl/topic-02/topic-02.enzh.mp4?v=1793393888-24362026-10-27yes https://exercises.lol/videos/ib_history_hl/topic-032026-10-30https://exercises.lol/video-media/ib_history_hl/topic-03/topic-03.thumb.jpg?v=1793392511The historical investigationOn 30 June 1936 the Emperor of Ethiopia, Haile Selassie, spoke to the League of Nations in Geneva. Italy had invaded in October 1935. In December the British…https://exercises.lol/video-media/ib_history_hl/topic-03/topic-03.enzh.mp4?v=1793392511-23132026-10-27yes https://exercises.lol/videos/ib_history_hl/topic-042026-10-30https://exercises.lol/video-media/ib_history_hl/topic-04/topic-04.thumb.jpg?v=1793397624Regional depth: the HL optionIn 1853 four American warships sailed into Edo Bay and demanded that Japan open its ports. Fifty years later Japan had a constitution, railways and a modern…https://exercises.lol/video-media/ib_history_hl/topic-04/topic-04.enzh.mp4?v=1793397624-23172026-10-29yes https://exercises.lol/videos/ib_history_sl/topic-012026-10-30https://exercises.lol/video-media/ib_history_sl/topic-01/topic-01.thumb.jpg?v=1793393864Sources and the prescribed subjectOn the twentieth of September 1939 a London newspaper printed a cartoon by David Low. Hitler and Stalin bow politely over the body of a dead soldier, Poland.…https://exercises.lol/video-media/ib_history_sl/topic-01/topic-01.enzh.mp4?v=1793393864-23542026-10-27yes https://exercises.lol/videos/ib_history_sl/topic-022026-10-30https://exercises.lol/video-media/ib_history_sl/topic-02/topic-02.thumb.jpg?v=1793393791World history topicsIn May 1928 the Nazi Party won twelve of four hundred and ninety-one seats in the German parliament. Four and a half years later, its leader was head of the…https://exercises.lol/video-media/ib_history_sl/topic-02/topic-02.enzh.mp4?v=1793393791-24362026-10-27yes https://exercises.lol/videos/ib_history_sl/topic-032026-10-30https://exercises.lol/video-media/ib_history_sl/topic-03/topic-03.thumb.jpg?v=1793392981The historical investigationOn 30 June 1936 the Emperor of Ethiopia, Haile Selassie, spoke to the League of Nations in Geneva. Italy had invaded in October 1935. In December the British…https://exercises.lol/video-media/ib_history_sl/topic-03/topic-03.enzh.mp4?v=1793392981-23132026-10-27yes https://exercises.lol/videos/ib_language_a_language_literature_hl/topic-012026-10-30https://exercises.lol/video-media/ib_language_a_language_literature_hl/topic-01/topic-01.thumb.jpg?v=1793400385Analysing non-literary textsIn 2013 Chinese students started an online campaign against food waste, the Clean Plate campaign. Posters showed an empty plate and a short slogan. A few words…https://exercises.lol/video-media/ib_language_a_language_literature_hl/topic-01/topic-01.enzh.mp4?v=1793400385-23052026-10-30yes https://exercises.lol/videos/ib_language_a_language_literature_hl/topic-022026-10-30https://exercises.lol/video-media/ib_language_a_language_literature_hl/topic-02/topic-02.thumb.jpg?v=1793401342Comparing literary worksIn 1879 Henrik Ibsen's play A Doll's House ended with a wife leaving her husband and children. Fifteen years later, Kate Chopin's short story The Story of an…https://exercises.lol/video-media/ib_language_a_language_literature_hl/topic-02/topic-02.enzh.mp4?v=1793401342-22492026-10-30yes https://exercises.lol/videos/ib_language_a_language_literature_hl/topic-032026-10-30https://exercises.lol/video-media/ib_language_a_language_literature_hl/topic-03/topic-03.thumb.jpg?v=1793401505The individual oralIn April 2016 a skincare company released a four-minute film in China, Marriage Market Takeover. Parents had posted their daughters' details at the marriage…https://exercises.lol/video-media/ib_language_a_language_literature_hl/topic-03/topic-03.enzh.mp4?v=1793401505-22612026-10-30yes https://exercises.lol/videos/ib_language_a_language_literature_hl/topic-042026-10-30https://exercises.lol/video-media/ib_language_a_language_literature_hl/topic-04/topic-04.thumb.jpg?v=1793400795The HL essayStudents often begin with a large topic, such as women in A Doll's House. After fifteen hundred words they have said a little about many things and proved…https://exercises.lol/video-media/ib_language_a_language_literature_hl/topic-04/topic-04.enzh.mp4?v=1793400795-22142026-10-30yes https://exercises.lol/videos/ib_language_a_language_literature_sl/topic-012026-10-30https://exercises.lol/video-media/ib_language_a_language_literature_sl/topic-01/topic-01.thumb.jpg?v=1793400797Analysing non-literary textsIn 2013 Chinese students started an online campaign against food waste, the Clean Plate campaign. Posters showed an empty plate and a short slogan. A few words…https://exercises.lol/video-media/ib_language_a_language_literature_sl/topic-01/topic-01.enzh.mp4?v=1793400797-23052026-10-30yes https://exercises.lol/videos/ib_language_a_language_literature_sl/topic-022026-10-30https://exercises.lol/video-media/ib_language_a_language_literature_sl/topic-02/topic-02.thumb.jpg?v=1793401473Comparing literary worksIn 1879 Henrik Ibsen's play A Doll's House ended with a wife leaving her husband and children. Fifteen years later, Kate Chopin's short story The Story of an…https://exercises.lol/video-media/ib_language_a_language_literature_sl/topic-02/topic-02.enzh.mp4?v=1793401473-22492026-10-30yes https://exercises.lol/videos/ib_language_a_language_literature_sl/topic-032026-10-30https://exercises.lol/video-media/ib_language_a_language_literature_sl/topic-03/topic-03.thumb.jpg?v=1793400714The individual oralIn April 2016 a skincare company released a four-minute film in China, Marriage Market Takeover. Parents had posted their daughters' details at the marriage…https://exercises.lol/video-media/ib_language_a_language_literature_sl/topic-03/topic-03.enzh.mp4?v=1793400714-22612026-10-30yes https://exercises.lol/videos/ib_language_a_literature_hl/topic-012026-10-30https://exercises.lol/video-media/ib_language_a_literature_hl/topic-01/topic-01.thumb.jpg?v=1793402091Close reading and Paper 1In about 1861 Emily Dickinson wrote a short poem about hope: twelve lines, no title, many dashes. She never published it. Only about ten of her almost eighteen…https://exercises.lol/video-media/ib_language_a_literature_hl/topic-01/topic-01.enzh.mp4?v=1793402091-22492026-10-30yes https://exercises.lol/videos/ib_language_a_literature_hl/topic-022026-10-30https://exercises.lol/video-media/ib_language_a_literature_hl/topic-02/topic-02.thumb.jpg?v=1793400675Comparing literary worksTwo kings hear a prophecy. In ancient Athens, Oedipus is told he will kill his father and marry his mother; he runs away to escape it, and runs straight into…https://exercises.lol/video-media/ib_language_a_literature_hl/topic-02/topic-02.enzh.mp4?v=1793400675-22822026-10-30yes https://exercises.lol/videos/ib_language_a_literature_hl/topic-032026-10-30https://exercises.lol/video-media/ib_language_a_literature_hl/topic-03/topic-03.thumb.jpg?v=1793401541The individual oralIn 1892 Charlotte Perkins Gilman published a story about a young mother, told by her doctor husband not to write, who keeps a secret diary and slowly loses her…https://exercises.lol/video-media/ib_language_a_literature_hl/topic-03/topic-03.enzh.mp4?v=1793401541-22412026-10-30yes https://exercises.lol/videos/ib_language_a_literature_hl/topic-042026-10-30https://exercises.lol/video-media/ib_language_a_literature_hl/topic-04/topic-04.thumb.jpg?v=1793400682The HL essayEmily Dickinson wrote most of her poems around 1860, in small hand-sewn booklets nobody saw until after her death. Her first editors corrected them: they…https://exercises.lol/video-media/ib_language_a_literature_hl/topic-04/topic-04.enzh.mp4?v=1793400682-22242026-10-30yes https://exercises.lol/videos/ib_language_a_literature_sl/topic-012026-10-30https://exercises.lol/video-media/ib_language_a_literature_sl/topic-01/topic-01.thumb.jpg?v=1793400680Close reading and Paper 1In about 1861 Emily Dickinson wrote a short poem about hope: twelve lines, no title, many dashes. She never published it. Only about ten of her almost eighteen…https://exercises.lol/video-media/ib_language_a_literature_sl/topic-01/topic-01.enzh.mp4?v=1793400680-22492026-10-30yes https://exercises.lol/videos/ib_language_a_literature_sl/topic-022026-10-30https://exercises.lol/video-media/ib_language_a_literature_sl/topic-02/topic-02.thumb.jpg?v=1793401011Comparing literary worksTwo kings hear a prophecy. In ancient Athens, Oedipus is told he will kill his father and marry his mother; he runs away to escape it, and runs straight into…https://exercises.lol/video-media/ib_language_a_literature_sl/topic-02/topic-02.enzh.mp4?v=1793401011-22822026-10-30yes https://exercises.lol/videos/ib_language_a_literature_sl/topic-032026-10-30https://exercises.lol/video-media/ib_language_a_literature_sl/topic-03/topic-03.thumb.jpg?v=1793401561The individual oralIn 1892 Charlotte Perkins Gilman published a story about a young mother, told by her doctor husband not to write, who keeps a secret diary and slowly loses her…https://exercises.lol/video-media/ib_language_a_literature_sl/topic-03/topic-03.enzh.mp4?v=1793401561-22412026-10-30yes https://exercises.lol/videos/ib_language_ab_initio_sl/session4-012026-10-29https://exercises.lol/video-media/ib_language_ab_initio_sl/session4-01/session4-01.thumb.jpg?v=1793297729Supported focus — Spanish introductions and agreementMe llamo gives a name; soy describes identity or role. “Me llamo Inés. Soy estudiante.” Answer a name question with me llamo, not a word-for-word English…https://exercises.lol/video-media/ib_language_ab_initio_sl/session4-01/session4-01.enzh.mp4?v=1793297729-22432026-10-29yes https://exercises.lol/videos/ib_language_ab_initio_sl/session4-022026-10-30https://exercises.lol/video-media/ib_language_ab_initio_sl/session4-02/session4-02.thumb.jpg?v=1793397892Supported focus — Spanish routine, time and purposeful messagesA purposeful message gives the reader usable arrangements. Include why, day, time, place, needed items and a question or request. “A las cuatro” gives a clock…https://exercises.lol/video-media/ib_language_ab_initio_sl/session4-02/session4-02.enzh.mp4?v=1793397892-23772026-10-29yes https://exercises.lol/videos/ib_language_ab_initio_sl/session4-032026-10-30https://exercises.lol/video-media/ib_language_ab_initio_sl/session4-03/session4-03.thumb.jpg?v=1793397721Supported focus — Spanish visual description and cultural comparisonUse the actual original market illustration. Say “En la imagen hay tres personas y una mesa”. Location phrases include al lado de (beside) and delante de (in…https://exercises.lol/video-media/ib_language_ab_initio_sl/session4-03/session4-03.enzh.mp4?v=1793397721-22782026-10-29yes https://exercises.lol/videos/ib_language_b_hl/session4-012026-10-30https://exercises.lol/video-media/ib_language_b_hl/session4-01/session4-01.thumb.jpg?v=1793398133Supported focus — English audience, register and purposeful writingA proposal identifies a need, a practical plan and expected benefits. Use polite recommendations for a principal; a friendly message can address a peer…https://exercises.lol/video-media/ib_language_b_hl/session4-01/session4-01.enzh.mp4?v=1793398133-25012026-10-29yes https://exercises.lol/videos/ib_language_b_hl/session4-022026-10-30https://exercises.lol/video-media/ib_language_b_hl/session4-02/session4-02.thumb.jpg?v=1793397834Supported focus — English listening and reading inferenceRead for the whole message before selecting a detail. A contrast marker can qualify a positive evaluation. Teacher-read rehearsal : close the script while a…https://exercises.lol/video-media/ib_language_b_hl/session4-02/session4-02.enzh.mp4?v=1793397834-22872026-10-29yes https://exercises.lol/videos/ib_language_b_hl/session4-032026-10-30https://exercises.lol/video-media/ib_language_b_hl/session4-03/session4-03.thumb.jpg?v=1793398077Supported focus — English oral communication and follow-upAt SL, use the supplied original repair notice image for a thematic rehearsal about community access; it is not an official oral picture. At HL, begin an…https://exercises.lol/video-media/ib_language_b_hl/session4-03/session4-03.enzh.mp4?v=1793398077-23332026-10-29yes https://exercises.lol/videos/ib_language_b_hl/session4-042026-10-30https://exercises.lol/video-media/ib_language_b_hl/session4-04/session4-04.thumb.jpg?v=1793398033Supported focus — English literary extract and oral developmentHL English B extract work uses clear language to explain character, voice and situation. In Text A, the first-person speaker carries out the work while…https://exercises.lol/video-media/ib_language_b_hl/session4-04/session4-04.enzh.mp4?v=1793398033-23922026-10-29yes https://exercises.lol/videos/ib_language_b_sl/session4-012026-10-30https://exercises.lol/video-media/ib_language_b_sl/session4-01/session4-01.thumb.jpg?v=1793398173Supported focus — English audience, register and purposeful writingA proposal identifies a need, a practical plan and expected benefits. Use polite recommendations for a principal; a friendly message can address a peer…https://exercises.lol/video-media/ib_language_b_sl/session4-01/session4-01.enzh.mp4?v=1793398173-24112026-10-29yes https://exercises.lol/videos/ib_language_b_sl/session4-022026-10-30https://exercises.lol/video-media/ib_language_b_sl/session4-02/session4-02.thumb.jpg?v=1793398402Supported focus — English listening and reading inferenceRead for the whole message before selecting a detail. A contrast marker can qualify a positive evaluation. Teacher-read rehearsal : close the script while a…https://exercises.lol/video-media/ib_language_b_sl/session4-02/session4-02.enzh.mp4?v=1793398402-22872026-10-29yes https://exercises.lol/videos/ib_language_b_sl/session4-032026-10-30https://exercises.lol/video-media/ib_language_b_sl/session4-03/session4-03.thumb.jpg?v=1793398424Supported focus — English oral communication and follow-upAt SL, use the supplied original repair notice image for a thematic rehearsal about community access; it is not an official oral picture. At HL, begin an…https://exercises.lol/video-media/ib_language_b_sl/session4-03/session4-03.enzh.mp4?v=1793398424-23332026-10-29yes https://exercises.lol/videos/ib_literature_performance_sl/topic-012026-10-30https://exercises.lol/video-media/ib_literature_performance_sl/topic-01/topic-01.thumb.jpg?v=1793400964Reading literature for performanceI can take any empty space and call it a bare stage, wrote the director Peter Brook in 1968. A man walks across this empty space whilst someone else is…https://exercises.lol/video-media/ib_literature_performance_sl/topic-01/topic-01.enzh.mp4?v=1793400964-22142026-10-30yes https://exercises.lol/videos/ib_literature_performance_sl/topic-022026-10-30https://exercises.lol/video-media/ib_literature_performance_sl/topic-02/topic-02.thumb.jpg?v=1793402149From non-dramatic literature to live theatreIn Lu Xun's story, a man remembers the year he was twelve, working behind the counter of a wine shop. Kong Yiji is the only customer who drinks standing up but…https://exercises.lol/video-media/ib_literature_performance_sl/topic-02/topic-02.enzh.mp4?v=1793402149-21862026-10-30yes https://exercises.lol/videos/ib_literature_performance_sl/topic-032026-10-30https://exercises.lol/video-media/ib_literature_performance_sl/topic-03/topic-03.thumb.jpg?v=1793402113Individual performance choices and analysisIn Act 2 of Macbeth, Macbeth is alone at night, about to murder King Duncan. Suddenly he sees a dagger in the air: is this a dagger which I see before me? A…https://exercises.lol/video-media/ib_literature_performance_sl/topic-03/topic-03.enzh.mp4?v=1793402113-21652026-10-30yes https://exercises.lol/videos/ib_mathematics_aa_hl/supported-focus-012026-10-31https://exercises.lol/video-media/ib_mathematics_aa_hl/supported-focus-01/supported-focus-01.thumb.jpg?v=1793407753Number and algebraThese are selected topics, not the whole syllabus, and every example is fictional. The highest common factor takes the smallest shared prime powers; the lowest…https://exercises.lol/video-media/ib_mathematics_aa_hl/supported-focus-01/supported-focus-01.enzh.mp4?v=1793407753-24322026-10-29yes https://exercises.lol/videos/ib_mathematics_aa_hl/supported-focus-022026-10-29https://exercises.lol/video-media/ib_mathematics_aa_hl/supported-focus-02/supported-focus-02.thumb.jpg?v=1793301893FunctionsThese are selected topics, not the whole syllabus, and every example is fictional. A function comes with its domain; in f g, g acts first; only a one-to-one…https://exercises.lol/video-media/ib_mathematics_aa_hl/supported-focus-02/supported-focus-02.enzh.mp4?v=1793301893-21412026-10-29yes https://exercises.lol/videos/ib_mathematics_aa_hl/supported-focus-032026-10-29https://exercises.lol/video-media/ib_mathematics_aa_hl/supported-focus-03/supported-focus-03.thumb.jpg?v=1793302635Geometry and trigonometryThese are selected topics, not the whole syllabus, and every example is fictional. Similar shapes scale lengths by k, areas by k squared and volumes by k…https://exercises.lol/video-media/ib_mathematics_aa_hl/supported-focus-03/supported-focus-03.enzh.mp4?v=1793302635-22452026-10-29yes https://exercises.lol/videos/ib_mathematics_aa_hl/supported-focus-042026-10-29https://exercises.lol/video-media/ib_mathematics_aa_hl/supported-focus-04/supported-focus-04.thumb.jpg?v=1793302236Statistics and probabilityThese are selected topics, not the whole syllabus, and every example is fictional. Compare an average and a spread, and remember a histogram shows frequency as…https://exercises.lol/video-media/ib_mathematics_aa_hl/supported-focus-04/supported-focus-04.enzh.mp4?v=1793302236-21982026-10-29yes https://exercises.lol/videos/ib_mathematics_aa_hl/supported-focus-052026-10-29https://exercises.lol/video-media/ib_mathematics_aa_hl/supported-focus-05/supported-focus-05.thumb.jpg?v=1793302921CalculusThese are selected topics, not the whole syllabus, and every example is fictional. The derivative is the gradient at a point; stationary points have gradient…https://exercises.lol/video-media/ib_mathematics_aa_hl/supported-focus-05/supported-focus-05.enzh.mp4?v=1793302921-23232026-10-29yes https://exercises.lol/videos/ib_mathematics_aa_hl/supported-focus-062026-10-29https://exercises.lol/video-media/ib_mathematics_aa_hl/supported-focus-06/supported-focus-06.thumb.jpg?v=1793302909School-supervised mathematical explorationThese are selected topics, not the whole syllabus, and every example is fictional. An exploration needs a focused question, honest data and mathematics you can…https://exercises.lol/video-media/ib_mathematics_aa_hl/supported-focus-06/supported-focus-06.enzh.mp4?v=1793302909-2732026-10-29yes https://exercises.lol/videos/ib_mathematics_aa_sl/supported-focus-012026-10-31https://exercises.lol/video-media/ib_mathematics_aa_sl/supported-focus-01/supported-focus-01.thumb.jpg?v=1793407886Number and algebraThese are selected topics, not the whole syllabus, and every example is fictional. The highest common factor takes the smallest shared prime powers; the lowest…https://exercises.lol/video-media/ib_mathematics_aa_sl/supported-focus-01/supported-focus-01.enzh.mp4?v=1793407886-22772026-10-29yes https://exercises.lol/videos/ib_mathematics_aa_sl/supported-focus-022026-10-29https://exercises.lol/video-media/ib_mathematics_aa_sl/supported-focus-02/supported-focus-02.thumb.jpg?v=1793303186FunctionsThese are selected topics, not the whole syllabus, and every example is fictional. A function comes with its domain; in f g, g acts first; only a one-to-one…https://exercises.lol/video-media/ib_mathematics_aa_sl/supported-focus-02/supported-focus-02.enzh.mp4?v=1793303186-21412026-10-24yes https://exercises.lol/videos/ib_mathematics_aa_sl/supported-focus-032026-10-29https://exercises.lol/video-media/ib_mathematics_aa_sl/supported-focus-03/supported-focus-03.thumb.jpg?v=1793303287Geometry and trigonometryThese are selected topics, not the whole syllabus, and every example is fictional. Similar shapes scale lengths by k, areas by k squared and volumes by k…https://exercises.lol/video-media/ib_mathematics_aa_sl/supported-focus-03/supported-focus-03.enzh.mp4?v=1793303287-21922026-10-29yes https://exercises.lol/videos/ib_mathematics_aa_sl/supported-focus-042026-10-29https://exercises.lol/video-media/ib_mathematics_aa_sl/supported-focus-04/supported-focus-04.thumb.jpg?v=1793303440Statistics and probabilityThese are selected topics, not the whole syllabus, and every example is fictional. Compare an average and a spread, and remember a histogram shows frequency as…https://exercises.lol/video-media/ib_mathematics_aa_sl/supported-focus-04/supported-focus-04.enzh.mp4?v=1793303440-21982026-10-29yes https://exercises.lol/videos/ib_mathematics_aa_sl/supported-focus-052026-10-29https://exercises.lol/video-media/ib_mathematics_aa_sl/supported-focus-05/supported-focus-05.thumb.jpg?v=1793303427CalculusThese are selected topics, not the whole syllabus, and every example is fictional. The derivative is the gradient at a point; stationary points have gradient…https://exercises.lol/video-media/ib_mathematics_aa_sl/supported-focus-05/supported-focus-05.enzh.mp4?v=1793303427-21302026-10-29yes https://exercises.lol/videos/ib_mathematics_aa_sl/supported-focus-062026-10-29https://exercises.lol/video-media/ib_mathematics_aa_sl/supported-focus-06/supported-focus-06.thumb.jpg?v=1793303501School-supervised mathematical explorationThese are selected topics, not the whole syllabus, and every example is fictional. An exploration needs a focused question, honest data and mathematics you can…https://exercises.lol/video-media/ib_mathematics_aa_sl/supported-focus-06/supported-focus-06.enzh.mp4?v=1793303501-2732026-10-29yes https://exercises.lol/videos/ib_mathematics_ai_hl/supported-focus-012026-10-31https://exercises.lol/video-media/ib_mathematics_ai_hl/supported-focus-01/supported-focus-01.thumb.jpg?v=1793408045Number and algebraThese are selected topics, not the whole syllabus, and every example is fictional. The highest common factor takes the smallest shared prime powers; the lowest…https://exercises.lol/video-media/ib_mathematics_ai_hl/supported-focus-01/supported-focus-01.enzh.mp4?v=1793408045-24332026-10-29yes https://exercises.lol/videos/ib_mathematics_ai_hl/supported-focus-022026-10-29https://exercises.lol/video-media/ib_mathematics_ai_hl/supported-focus-02/supported-focus-02.thumb.jpg?v=1793303620FunctionsThese are selected topics, not the whole syllabus, and every example is fictional. A function comes with its domain; in f g, g acts first; only a one-to-one…https://exercises.lol/video-media/ib_mathematics_ai_hl/supported-focus-02/supported-focus-02.enzh.mp4?v=1793303620-22082026-10-24yes https://exercises.lol/videos/ib_mathematics_ai_hl/supported-focus-032026-10-29https://exercises.lol/video-media/ib_mathematics_ai_hl/supported-focus-03/supported-focus-03.thumb.jpg?v=1793303736Geometry and trigonometryThese are selected topics, not the whole syllabus, and every example is fictional. Similar shapes scale lengths by k, areas by k squared and volumes by k…https://exercises.lol/video-media/ib_mathematics_ai_hl/supported-focus-03/supported-focus-03.enzh.mp4?v=1793303736-21852026-10-29yes https://exercises.lol/videos/ib_mathematics_ai_hl/supported-focus-042026-10-29https://exercises.lol/video-media/ib_mathematics_ai_hl/supported-focus-04/supported-focus-04.thumb.jpg?v=1793303958Statistics and probabilityThese are selected topics, not the whole syllabus, and every example is fictional. Compare an average and a spread, and remember a histogram shows frequency as…https://exercises.lol/video-media/ib_mathematics_ai_hl/supported-focus-04/supported-focus-04.enzh.mp4?v=1793303958-23262026-10-29yes https://exercises.lol/videos/ib_mathematics_ai_hl/supported-focus-052026-10-29https://exercises.lol/video-media/ib_mathematics_ai_hl/supported-focus-05/supported-focus-05.thumb.jpg?v=1793304247CalculusThese are selected topics, not the whole syllabus, and every example is fictional. The derivative is the gradient at a point; stationary points have gradient…https://exercises.lol/video-media/ib_mathematics_ai_hl/supported-focus-05/supported-focus-05.enzh.mp4?v=1793304247-23242026-10-24yes https://exercises.lol/videos/ib_mathematics_ai_hl/supported-focus-062026-10-29https://exercises.lol/video-media/ib_mathematics_ai_hl/supported-focus-06/supported-focus-06.thumb.jpg?v=1793304462School-supervised mathematical explorationThese are selected topics, not the whole syllabus, and every example is fictional. An exploration needs a focused question, honest data and mathematics you can…https://exercises.lol/video-media/ib_mathematics_ai_hl/supported-focus-06/supported-focus-06.enzh.mp4?v=1793304462-2732026-10-29yes https://exercises.lol/videos/ib_mathematics_ai_sl/supported-focus-012026-10-31https://exercises.lol/video-media/ib_mathematics_ai_sl/supported-focus-01/supported-focus-01.thumb.jpg?v=1793407989Number and algebraThese are selected topics, not the whole syllabus, and every example is fictional. The highest common factor takes the smallest shared prime powers; the lowest…https://exercises.lol/video-media/ib_mathematics_ai_sl/supported-focus-01/supported-focus-01.enzh.mp4?v=1793407989-23082026-10-24yes https://exercises.lol/videos/ib_mathematics_ai_sl/supported-focus-022026-10-29https://exercises.lol/video-media/ib_mathematics_ai_sl/supported-focus-02/supported-focus-02.thumb.jpg?v=1793304660FunctionsThese are selected topics, not the whole syllabus, and every example is fictional. A function comes with its domain; in f g, g acts first; only a one-to-one…https://exercises.lol/video-media/ib_mathematics_ai_sl/supported-focus-02/supported-focus-02.enzh.mp4?v=1793304660-22082026-10-24yes https://exercises.lol/videos/ib_mathematics_ai_sl/supported-focus-032026-10-29https://exercises.lol/video-media/ib_mathematics_ai_sl/supported-focus-03/supported-focus-03.thumb.jpg?v=1793304789Geometry and trigonometryThese are selected topics, not the whole syllabus, and every example is fictional. Similar shapes scale lengths by k, areas by k squared and volumes by k…https://exercises.lol/video-media/ib_mathematics_ai_sl/supported-focus-03/supported-focus-03.enzh.mp4?v=1793304789-21332026-10-29yes https://exercises.lol/videos/ib_mathematics_ai_sl/supported-focus-042026-10-29https://exercises.lol/video-media/ib_mathematics_ai_sl/supported-focus-04/supported-focus-04.thumb.jpg?v=1793304929Statistics and probabilityThese are selected topics, not the whole syllabus, and every example is fictional. Compare an average and a spread, and remember a histogram shows frequency as…https://exercises.lol/video-media/ib_mathematics_ai_sl/supported-focus-04/supported-focus-04.enzh.mp4?v=1793304929-22632026-10-29yes https://exercises.lol/videos/ib_mathematics_ai_sl/supported-focus-052026-10-29https://exercises.lol/video-media/ib_mathematics_ai_sl/supported-focus-05/supported-focus-05.thumb.jpg?v=1793305055CalculusThese are selected topics, not the whole syllabus, and every example is fictional. The derivative is the gradient at a point; stationary points have gradient…https://exercises.lol/video-media/ib_mathematics_ai_sl/supported-focus-05/supported-focus-05.enzh.mp4?v=1793305055-21302026-10-29yes https://exercises.lol/videos/ib_mathematics_ai_sl/supported-focus-062026-10-29https://exercises.lol/video-media/ib_mathematics_ai_sl/supported-focus-06/supported-focus-06.thumb.jpg?v=1793305117School-supervised mathematical explorationThese are selected topics, not the whole syllabus, and every example is fictional. An exploration needs a focused question, honest data and mathematics you can…https://exercises.lol/video-media/ib_mathematics_ai_sl/supported-focus-06/supported-focus-06.enzh.mp4?v=1793305117-2732026-10-29yes https://exercises.lol/videos/ib_music_hl/topic-012026-10-29https://exercises.lol/video-media/ib_music_hl/topic-01/topic-01.thumb.jpg?v=1793305587Exploring music in contextThe exploration portfolio is written work showing engagement with diverse music, plus practical exercises in creating and performing, focused through the four…https://exercises.lol/video-media/ib_music_hl/topic-01/topic-01.enzh.mp4?v=1793305587-21472026-10-29yes https://exercises.lol/videos/ib_music_hl/topic-022026-11-08https://exercises.lol/video-media/ib_music_hl/topic-02/topic-02.thumb.jpg?v=1794114058Experimenting with musicWhy it matters. In 1964 the young composer Steve Reich recorded a street preacher in San Francisco shouting "It's gonna rain!". Back in his studio he made two…https://exercises.lol/video-media/ib_music_hl/topic-02/topic-02.enzh.mp4?v=1794114058-25772026-10-27yes https://exercises.lol/videos/ib_music_hl/topic-032026-10-29https://exercises.lol/video-media/ib_music_hl/topic-03/topic-03.thumb.jpg?v=1793306027Presenting musicPresenting music is a collection of finished works: presenting as a creator, through composition or improvisation; presenting as a performer, solo or ensemble…https://exercises.lol/video-media/ib_music_hl/topic-03/topic-03.enzh.mp4?v=1793306027-21302026-10-29yes https://exercises.lol/videos/ib_music_hl/topic-042026-11-08https://exercises.lol/video-media/ib_music_hl/topic-04/topic-04.thumb.jpg?v=1794118482HL: The contemporary music makerWhy it matters. In 2008 the American radio network NPR began filming musicians playing short, quiet sets behind a presenter's desk in its Washington office.…https://exercises.lol/video-media/ib_music_hl/topic-04/topic-04.enzh.mp4?v=1794118482-24552026-10-27yes https://exercises.lol/videos/ib_music_sl/topic-012026-10-29https://exercises.lol/video-media/ib_music_sl/topic-01/topic-01.thumb.jpg?v=1793311286Exploring music in contextThe exploration portfolio is written work showing engagement with diverse music, plus practical exercises in creating and performing, focused through the four…https://exercises.lol/video-media/ib_music_sl/topic-01/topic-01.enzh.mp4?v=1793311286-21462026-10-29yes https://exercises.lol/videos/ib_music_sl/topic-022026-10-29https://exercises.lol/video-media/ib_music_sl/topic-02/topic-02.thumb.jpg?v=1793313803Experimenting with musicThe experimentation report gives a rationale and a commentary for each process, supporting practical evidence of experiments in creating and performing, in two…https://exercises.lol/video-media/ib_music_sl/topic-02/topic-02.enzh.mp4?v=1793313803-21492026-10-29yes https://exercises.lol/videos/ib_music_sl/topic-032026-10-29https://exercises.lol/video-media/ib_music_sl/topic-03/topic-03.thumb.jpg?v=1793307635Presenting musicPresenting music is a collection of finished works: presenting as a creator, through composition or improvisation; presenting as a performer, solo or ensemble…https://exercises.lol/video-media/ib_music_sl/topic-03/topic-03.enzh.mp4?v=1793307635-21302026-10-29yes https://exercises.lol/videos/ib_philosophy_hl/topic-012026-10-31https://exercises.lol/video-media/ib_philosophy_hl/topic-01/topic-01.thumb.jpg?v=1793405239Being humanIn 1848 an explosion drove an iron rod through the head of Phineas Gage, a railway worker in Vermont. He survived, and could walk and talk. But his friends…https://exercises.lol/video-media/ib_philosophy_hl/topic-01/topic-01.enzh.mp4?v=1793405239-23152026-10-28yes https://exercises.lol/videos/ib_philosophy_hl/topic-022026-10-30https://exercises.lol/video-media/ib_philosophy_hl/topic-02/topic-02.thumb.jpg?v=1793398750Optional themes and the prescribed textA runaway train is heading towards five workers on the track. You can pull a lever and send it onto a side track, where it will kill one worker instead. Should…https://exercises.lol/video-media/ib_philosophy_hl/topic-02/topic-02.enzh.mp4?v=1793398750-22942026-10-29yes https://exercises.lol/videos/ib_philosophy_hl/topic-032026-10-30https://exercises.lol/video-media/ib_philosophy_hl/topic-03/topic-03.thumb.jpg?v=1793398724The philosophical analysisImagine an advert for an AI companion app. A young person sits alone at night, talking to a phone. The slogan: always there, always understands you. Can a…https://exercises.lol/video-media/ib_philosophy_hl/topic-03/topic-03.enzh.mp4?v=1793398724-21902026-10-29yes https://exercises.lol/videos/ib_philosophy_hl/topic-042026-10-30https://exercises.lol/video-media/ib_philosophy_hl/topic-04/topic-04.thumb.jpg?v=1793398854Philosophy and contemporary issuesIn 1950 Alan Turing asked: can machines think? He replaced the question with a test: if a judge talking by text cannot tell a machine from a human, we should…https://exercises.lol/video-media/ib_philosophy_hl/topic-04/topic-04.enzh.mp4?v=1793398854-22182026-10-29yes https://exercises.lol/videos/ib_philosophy_sl/topic-012026-10-30https://exercises.lol/video-media/ib_philosophy_sl/topic-01/topic-01.thumb.jpg?v=1793395260Being humanIn 1848 an explosion drove an iron rod through the head of Phineas Gage, a railway worker in Vermont. He survived, and could walk and talk. But his friends…https://exercises.lol/video-media/ib_philosophy_sl/topic-01/topic-01.enzh.mp4?v=1793395260-23152026-10-28yes https://exercises.lol/videos/ib_philosophy_sl/topic-022026-10-30https://exercises.lol/video-media/ib_philosophy_sl/topic-02/topic-02.thumb.jpg?v=1793398864Optional themes and the prescribed textA runaway train is heading towards five workers on the track. You can pull a lever and send it onto a side track, where it will kill one worker instead. Should…https://exercises.lol/video-media/ib_philosophy_sl/topic-02/topic-02.enzh.mp4?v=1793398864-22942026-10-29yes https://exercises.lol/videos/ib_philosophy_sl/topic-032026-10-30https://exercises.lol/video-media/ib_philosophy_sl/topic-03/topic-03.thumb.jpg?v=1793398739The philosophical analysisImagine an advert for an AI companion app. A young person sits alone at night, talking to a phone. The slogan: always there, always understands you. Can a…https://exercises.lol/video-media/ib_philosophy_sl/topic-03/topic-03.enzh.mp4?v=1793398739-21902026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-012026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-01/supported-focus-01.thumb.jpg?v=1793309100KinematicsA speedometer gives a reading at one moment. A journey average can hide stops and rapid changes in speed.https://exercises.lol/video-media/ib_physics_hl/supported-focus-01/supported-focus-01.enzh.mp4?v=1793309100-22392026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-022026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-02/supported-focus-02.thumb.jpg?v=1793309333Forces and momentumA passenger continues moving when a vehicle brakes. The seat belt provides the force needed to change the passenger momentum 动量.https://exercises.lol/video-media/ib_physics_hl/supported-focus-02/supported-focus-02.enzh.mp4?v=1793309333-22362026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-032026-10-31https://exercises.lol/video-media/ib_physics_hl/supported-focus-03/supported-focus-03.thumb.jpg?v=1793408031Work, energy and powerA motor can transfer some input energy to lifting and the rest to heating. Useful output is part of the total energy transfer.https://exercises.lol/video-media/ib_physics_hl/supported-focus-03/supported-focus-03.enzh.mp4?v=1793408031-22282026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-042026-10-31https://exercises.lol/video-media/ib_physics_hl/supported-focus-04/supported-focus-04.thumb.jpg?v=1793408295Rigid body mechanicsA door is easier to open when pushed near its outer edge. Force size alone does not determine the turning effect.https://exercises.lol/video-media/ib_physics_hl/supported-focus-04/supported-focus-04.enzh.mp4?v=1793408295-22432026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-052026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-05/supported-focus-05.thumb.jpg?v=1793309402Galilean and special relativityTwo observers can assign different times between the same events. A clock reading has meaning only when the frame and events are specified.https://exercises.lol/video-media/ib_physics_hl/supported-focus-05/supported-focus-05.enzh.mp4?v=1793309402-22472026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-062026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-06/supported-focus-06.thumb.jpg?v=1793309694Thermal energy transfersTwo equal masses receive the same energy but show different temperature rises. Material properties determine how energy transfer changes temperature.https://exercises.lol/video-media/ib_physics_hl/supported-focus-06/supported-focus-06.enzh.mp4?v=1793309694-22492026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-072026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-07/supported-focus-07.thumb.jpg?v=1793309435Greenhouse effectOne cold day does not disprove a warming climate. Weather describes short-term conditions; climate describes distributions over longer times and regions.https://exercises.lol/video-media/ib_physics_hl/supported-focus-07/supported-focus-07.enzh.mp4?v=1793309435-22492026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-082026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-08/supported-focus-08.thumb.jpg?v=1793309636Gas lawsA sealed gas container changes pressure when heated. Celsius ratios cannot predict the pressure change because the gas model uses absolute temperature 绝对温度.https://exercises.lol/video-media/ib_physics_hl/supported-focus-08/supported-focus-08.enzh.mp4?v=1793309636-22582026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-092026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-09/supported-focus-09.thumb.jpg?v=1793309833ThermodynamicsCompressing a gas can warm it even without a heater. Work is another path for energy transfer into the system.https://exercises.lol/video-media/ib_physics_hl/supported-focus-09/supported-focus-09.enzh.mp4?v=1793309833-22402026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-102026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-10/supported-focus-10.thumb.jpg?v=1793309749Current and circuitsA lamp becomes dimmer when another is added in series. Current 电流 and energy transfer depend on the whole circuit, not only one lamp.https://exercises.lol/video-media/ib_physics_hl/supported-focus-10/supported-focus-10.enzh.mp4?v=1793309749-22242026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-112026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-11/supported-focus-11.thumb.jpg?v=1793309828Simple harmonic motionA swing gains a large amplitude when pushes arrive with the right timing. The forcing frequency and damping 阻尼 help determine the response.https://exercises.lol/video-media/ib_physics_hl/supported-focus-11/supported-focus-11.enzh.mp4?v=1793309828-22552026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-122026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-12/supported-focus-12.thumb.jpg?v=1793310052Wave modelA wave can carry energy across water while a floating marker mainly oscillates. Energy transfer and bulk transfer of matter are different.https://exercises.lol/video-media/ib_physics_hl/supported-focus-12/supported-focus-12.enzh.mp4?v=1793310052-22372026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-152026-10-31https://exercises.lol/video-media/ib_physics_hl/supported-focus-15/supported-focus-15.thumb.jpg?v=1793407344Doppler effectA recognizable spectral line appears at a longer wavelength in a distant source. Its shift can provide evidence of recession along the line of sight.https://exercises.lol/video-media/ib_physics_hl/supported-focus-15/supported-focus-15.enzh.mp4?v=1793407344-24872026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-162026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-16/supported-focus-16.thumb.jpg?v=1793310251Gravitational fieldsAn orbiting satellite is continuously falling while moving sideways. Being in orbit does not require gravity to vanish.https://exercises.lol/video-media/ib_physics_hl/supported-focus-16/supported-focus-16.enzh.mp4?v=1793310251-22312026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-172026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-17/supported-focus-17.thumb.jpg?v=1793310408Electric and magnetic fieldsA negatively charged particle experiences an electric force opposite to the field direction. Field direction is defined using a positive test charge 试探电荷.https://exercises.lol/video-media/ib_physics_hl/supported-focus-17/supported-focus-17.enzh.mp4?v=1793310408-22582026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-182026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-18/supported-focus-18.thumb.jpg?v=1793310690Motion in electromagnetic fieldsA charged particle curves in a uniform magnetic field. Its direction changes although the magnetic force 磁力 alone does not increase its kinetic energy.https://exercises.lol/video-media/ib_physics_hl/supported-focus-18/supported-focus-18.enzh.mp4?v=1793310690-23012026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-192026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-19/supported-focus-19.thumb.jpg?v=1793310416InductionA magnet beside a wire does not always produce a current. An induced electromotive force depends on changing magnetic flux linkage.https://exercises.lol/video-media/ib_physics_hl/supported-focus-19/supported-focus-19.enzh.mp4?v=1793310416-22492026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-202026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-20/supported-focus-20.thumb.jpg?v=1793310919Structure of the atomAn excited gas produces separate coloured lines rather than every wavelength. The pattern is evidence for discrete atomic energy differences.https://exercises.lol/video-media/ib_physics_hl/supported-focus-20/supported-focus-20.enzh.mp4?v=1793310919-22542026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-212026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-21/supported-focus-21.thumb.jpg?v=1793311029Quantum physicsBright low-frequency light can fail to eject electrons while dim higher-frequency light succeeds. Photon 光子 energy depends on frequency, not intensity alone.https://exercises.lol/video-media/ib_physics_hl/supported-focus-21/supported-focus-21.enzh.mp4?v=1793311029-22572026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-222026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-22/supported-focus-22.thumb.jpg?v=1793278144Radioactive decayA detector records counts even when the classroom source is removed. Background must be considered before attributing every count to the source.https://exercises.lol/video-media/ib_physics_hl/supported-focus-22/supported-focus-22.enzh.mp4?v=1793278144-22202026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-232026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-23/supported-focus-23.thumb.jpg?v=1793278254FissionA neutron can trigger a heavy nucleus to split, releasing energy and further neutrons. Whether the process becomes a chain reaction 链式反应 depends on what…https://exercises.lol/video-media/ib_physics_hl/supported-focus-23/supported-focus-23.enzh.mp4?v=1793278254-22762026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-242026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-24/supported-focus-24.thumb.jpg?v=1793311442Fusion and starsTwo stars can have the same apparent brightness while having different luminosities. Distance changes the flux 辐射通量密度 reaching an observer.https://exercises.lol/video-media/ib_physics_hl/supported-focus-24/supported-focus-24.enzh.mp4?v=1793311442-22202026-10-29yes https://exercises.lol/videos/ib_physics_hl/supported-focus-252026-10-29https://exercises.lol/video-media/ib_physics_hl/supported-focus-25/supported-focus-25.thumb.jpg?v=1793311779Experimental programmeA line passing near every data point is useful, but its gradient can still be uncertain. A graph is evidence for a model within the measurement range.https://exercises.lol/video-media/ib_physics_hl/supported-focus-25/supported-focus-25.enzh.mp4?v=1793311779-22452026-10-29yes https://exercises.lol/videos/ib_physics_sl/supported-focus-012026-10-29https://exercises.lol/video-media/ib_physics_sl/supported-focus-01/supported-focus-01.thumb.jpg?v=1793311667KinematicsA speedometer gives a reading at one moment. A journey average can hide stops and rapid changes in speed.https://exercises.lol/video-media/ib_physics_sl/supported-focus-01/supported-focus-01.enzh.mp4?v=1793311667-22392026-10-29yes https://exercises.lol/videos/ib_physics_sl/supported-focus-022026-10-29https://exercises.lol/video-media/ib_physics_sl/supported-focus-02/supported-focus-02.thumb.jpg?v=1793312228Forces and momentumA passenger continues moving when a vehicle brakes. The seat belt provides the force needed to change the passenger momentum 动量.https://exercises.lol/video-media/ib_physics_sl/supported-focus-02/supported-focus-02.enzh.mp4?v=1793312228-22382026-10-29yes https://exercises.lol/videos/ib_physics_sl/supported-focus-032026-10-31https://exercises.lol/video-media/ib_physics_sl/supported-focus-03/supported-focus-03.thumb.jpg?v=1793408181Work, energy and powerA motor can transfer some input energy to lifting and the rest to heating. Useful output is part of the total energy transfer.https://exercises.lol/video-media/ib_physics_sl/supported-focus-03/supported-focus-03.enzh.mp4?v=1793408181-22292026-10-29yes https://exercises.lol/videos/ib_physics_sl/supported-focus-042026-10-29https://exercises.lol/video-media/ib_physics_sl/supported-focus-04/supported-focus-04.thumb.jpg?v=1793312070Thermal energy transfersTwo equal masses receive the same energy but show different temperature rises. Material properties determine how energy transfer changes temperature.https://exercises.lol/video-media/ib_physics_sl/supported-focus-04/supported-focus-04.enzh.mp4?v=1793312070-22482026-10-29yes https://exercises.lol/videos/ib_physics_sl/supported-focus-052026-10-29https://exercises.lol/video-media/ib_physics_sl/supported-focus-05/supported-focus-05.thumb.jpg?v=1793312218Greenhouse effectOne cold day does not disprove a warming climate. Weather describes short-term conditions; climate describes distributions over longer times and regions.https://exercises.lol/video-media/ib_physics_sl/supported-focus-05/supported-focus-05.enzh.mp4?v=1793312218-22492026-10-29yes https://exercises.lol/videos/ib_physics_sl/supported-focus-062026-10-29https://exercises.lol/video-media/ib_physics_sl/supported-focus-06/supported-focus-06.thumb.jpg?v=1793316174Gas lawsA sealed gas container changes pressure when heated. Celsius ratios cannot predict the pressure change because the gas model uses absolute temperature 绝对温度.https://exercises.lol/video-media/ib_physics_sl/supported-focus-06/supported-focus-06.enzh.mp4?v=1793316174-22592026-10-29yes https://exercises.lol/videos/ib_physics_sl/supported-focus-072026-10-29https://exercises.lol/video-media/ib_physics_sl/supported-focus-07/supported-focus-07.thumb.jpg?v=1793316633Current and circuitsA lamp becomes dimmer when another is added in series. Current 电流 and energy transfer depend on the whole circuit, not only one lamp.https://exercises.lol/video-media/ib_physics_sl/supported-focus-07/supported-focus-07.enzh.mp4?v=1793316633-22182026-10-29yes https://exercises.lol/videos/ib_physics_sl/supported-focus-082026-10-29https://exercises.lol/video-media/ib_physics_sl/supported-focus-08/supported-focus-08.thumb.jpg?v=1793316673Simple harmonic motionA swing gains a large amplitude when pushes arrive with the right timing. The forcing frequency and damping 阻尼 help determine the response.https://exercises.lol/video-media/ib_physics_sl/supported-focus-08/supported-focus-08.enzh.mp4?v=1793316673-22502026-10-29yes https://exercises.lol/videos/ib_physics_sl/supported-focus-092026-10-29https://exercises.lol/video-media/ib_physics_sl/supported-focus-09/supported-focus-09.thumb.jpg?v=1793316291Wave modelA wave can carry energy across water while a floating marker mainly oscillates. Energy transfer and bulk transfer of matter are different.https://exercises.lol/video-media/ib_physics_sl/supported-focus-09/supported-focus-09.enzh.mp4?v=1793316291-22372026-10-29yes https://exercises.lol/videos/ib_physics_sl/supported-focus-122026-10-29https://exercises.lol/video-media/ib_physics_sl/supported-focus-12/supported-focus-12.thumb.jpg?v=1793316689Doppler effectA recognizable spectral line appears at a longer wavelength in a distant source. Its shift can provide evidence of recession along the line of sight.https://exercises.lol/video-media/ib_physics_sl/supported-focus-12/supported-focus-12.enzh.mp4?v=1793316689-22502026-10-29yes https://exercises.lol/videos/ib_physics_sl/supported-focus-132026-10-29https://exercises.lol/video-media/ib_physics_sl/supported-focus-13/supported-focus-13.thumb.jpg?v=1793317138Gravitational fieldsAn orbiting satellite is continuously falling while moving sideways. Being in orbit does not require gravity to vanish.https://exercises.lol/video-media/ib_physics_sl/supported-focus-13/supported-focus-13.enzh.mp4?v=1793317138-22302026-10-29yes https://exercises.lol/videos/ib_physics_sl/supported-focus-142026-10-29https://exercises.lol/video-media/ib_physics_sl/supported-focus-14/supported-focus-14.thumb.jpg?v=1793281822Electric and magnetic fieldsA negatively charged particle experiences an electric force opposite to the field direction. Field direction is defined using a positive test charge 试探电荷.https://exercises.lol/video-media/ib_physics_sl/supported-focus-14/supported-focus-14.enzh.mp4?v=1793281822-22572026-10-24yes https://exercises.lol/videos/ib_physics_sl/supported-focus-152026-10-29https://exercises.lol/video-media/ib_physics_sl/supported-focus-15/supported-focus-15.thumb.jpg?v=1793318013Motion in electromagnetic fieldsA charged particle curves in a uniform magnetic field. Its direction changes although the magnetic force 磁力 alone does not increase its kinetic energy.https://exercises.lol/video-media/ib_physics_sl/supported-focus-15/supported-focus-15.enzh.mp4?v=1793318013-23032026-10-29yes https://exercises.lol/videos/ib_physics_sl/supported-focus-162026-10-29https://exercises.lol/video-media/ib_physics_sl/supported-focus-16/supported-focus-16.thumb.jpg?v=1793318322Structure of the atomAn excited gas produces separate coloured lines rather than every wavelength. The pattern is evidence for discrete atomic energy differences.https://exercises.lol/video-media/ib_physics_sl/supported-focus-16/supported-focus-16.enzh.mp4?v=1793318322-22532026-10-29yes https://exercises.lol/videos/ib_physics_sl/supported-focus-172026-10-30https://exercises.lol/video-media/ib_physics_sl/supported-focus-17/supported-focus-17.thumb.jpg?v=1793318582Radioactive decayA detector records counts even when the classroom source is removed. Background must be considered before attributing every count to the source.https://exercises.lol/video-media/ib_physics_sl/supported-focus-17/supported-focus-17.enzh.mp4?v=1793318582-22202026-10-29yes https://exercises.lol/videos/ib_physics_sl/supported-focus-182026-10-30https://exercises.lol/video-media/ib_physics_sl/supported-focus-18/supported-focus-18.thumb.jpg?v=1793318880FissionA neutron can trigger a heavy nucleus to split, releasing energy and further neutrons. Whether the process becomes a chain reaction 链式反应 depends on what…https://exercises.lol/video-media/ib_physics_sl/supported-focus-18/supported-focus-18.enzh.mp4?v=1793318880-22752026-10-29yes https://exercises.lol/videos/ib_physics_sl/supported-focus-192026-10-30https://exercises.lol/video-media/ib_physics_sl/supported-focus-19/supported-focus-19.thumb.jpg?v=1793319175Fusion and starsTwo stars can have the same apparent brightness while having different luminosities. Distance changes the flux 辐射通量密度 reaching an observer.https://exercises.lol/video-media/ib_physics_sl/supported-focus-19/supported-focus-19.enzh.mp4?v=1793319175-22142026-10-29yes https://exercises.lol/videos/ib_physics_sl/supported-focus-202026-10-30https://exercises.lol/video-media/ib_physics_sl/supported-focus-20/supported-focus-20.thumb.jpg?v=1793319506Experimental programmeA line passing near every data point is useful, but its gradient can still be uncertain. A graph is evidence for a model within the measurement range.https://exercises.lol/video-media/ib_physics_sl/supported-focus-20/supported-focus-20.enzh.mp4?v=1793319506-22462026-10-29yes https://exercises.lol/videos/ib_psychology_hl/topic-012026-11-08https://exercises.lol/video-media/ib_psychology_hl/topic-01/topic-01.thumb.jpg?v=1794122496The three approachesWhy it matters. Every June about 13 million students in China sit the gaokao. In the weeks before it, many sleep badly, lose their appetite and forget things…https://exercises.lol/video-media/ib_psychology_hl/topic-01/topic-01.enzh.mp4?v=1794122496-210562026-10-27yes https://exercises.lol/videos/ib_psychology_hl/topic-022026-11-08https://exercises.lol/video-media/ib_psychology_hl/topic-02/topic-02.thumb.jpg?v=1794114970Concepts and contextsWhy it matters. The World Health Organization estimates that about 280 million people live with depression. Is it a brain disease, a way of thinking, or a…https://exercises.lol/video-media/ib_psychology_hl/topic-02/topic-02.enzh.mp4?v=1794114970-29062026-10-27yes https://exercises.lol/videos/ib_psychology_hl/topic-032026-10-30https://exercises.lol/video-media/ib_psychology_hl/topic-03/topic-03.thumb.jpg?v=1793320058Research methods and the research proposalIn 2015, 270 researchers tried to repeat 100 published psychology studies. Only about a third, 36 percent, found a significant result again. Some of the…https://exercises.lol/video-media/ib_psychology_hl/topic-03/topic-03.enzh.mp4?v=1793320058-25272026-10-29yes https://exercises.lol/videos/ib_psychology_hl/topic-042026-10-30https://exercises.lol/video-media/ib_psychology_hl/topic-04/topic-04.thumb.jpg?v=1793320629HL extensions: culture, motivation, technology and dataIn 2021 China limited online games for under-18s to one hour on Friday, Saturday and Sunday evenings and on public holidays. The rule rests on three claims…https://exercises.lol/video-media/ib_psychology_hl/topic-04/topic-04.enzh.mp4?v=1793320629-24762026-10-29yes https://exercises.lol/videos/ib_psychology_sl/topic-012026-11-08https://exercises.lol/video-media/ib_psychology_sl/topic-01/topic-01.thumb.jpg?v=1794115557The three approachesWhy it matters. Every June about 13 million students in China sit the gaokao. In the weeks before it, many sleep badly, lose their appetite and forget things…https://exercises.lol/video-media/ib_psychology_sl/topic-01/topic-01.enzh.mp4?v=1794115557-210542026-10-27yes https://exercises.lol/videos/ib_psychology_sl/topic-022026-11-08https://exercises.lol/video-media/ib_psychology_sl/topic-02/topic-02.thumb.jpg?v=1794115611Concepts and contextsWhy it matters. The World Health Organization estimates that about 280 million people live with depression. Is it a brain disease, a way of thinking, or a…https://exercises.lol/video-media/ib_psychology_sl/topic-02/topic-02.enzh.mp4?v=1794115611-29002026-10-27yes https://exercises.lol/videos/ib_psychology_sl/topic-032026-10-29https://exercises.lol/video-media/ib_psychology_sl/topic-03/topic-03.thumb.jpg?v=1793308431Research methods and the research proposalIn 2015, 270 researchers tried to repeat 100 published psychology studies. Only about a third, 36 percent, found a significant result again. Some of the…https://exercises.lol/video-media/ib_psychology_sl/topic-03/topic-03.enzh.mp4?v=1793308431-25252026-10-29yes https://exercises.lol/videos/ib_religions_society_sl/session5-supported-preparation2026-10-30https://exercises.lol/video-media/ib_religions_society_sl/session5-supported-preparation/session5-supported-preparation.thumb.jpg?v=1793335813Religion and Society: future-course general preparationDefinitions of religion emphasize different features and can include or exclude different practices. State the criterion and test its implications; distinguish…https://exercises.lol/video-media/ib_religions_society_sl/session5-supported-preparation/session5-supported-preparation.enzh.mp4?v=1793335813-23322026-10-28yes https://exercises.lol/videos/ib_sports_science_hl/supported-focus-012026-10-29https://exercises.lol/video-media/ib_sports_science_hl/supported-focus-01/supported-focus-01.thumb.jpg?v=1793280653CommunicationThese are selected topics, not the whole syllabus, and every example is fictional. Cardiac output is heart rate times stroke volume, and it rises and recovers…https://exercises.lol/video-media/ib_sports_science_hl/supported-focus-01/supported-focus-01.enzh.mp4?v=1793280653-2672026-10-29yes https://exercises.lol/videos/ib_sports_science_hl/supported-focus-022026-10-29https://exercises.lol/video-media/ib_sports_science_hl/supported-focus-02/supported-focus-02.thumb.jpg?v=1793280594Hydration and nutritionThese are selected topics, not the whole syllabus, and every example is fictional. Sweat loss comes from a full water balance, not from the scale alone.…https://exercises.lol/video-media/ib_sports_science_hl/supported-focus-02/supported-focus-02.enzh.mp4?v=1793280594-2842026-10-29yes https://exercises.lol/videos/ib_sports_science_hl/supported-focus-042026-10-29https://exercises.lol/video-media/ib_sports_science_hl/supported-focus-04/supported-focus-04.thumb.jpg?v=1793280656Generating movement in the bodyThese are selected topics, not the whole syllabus, and every example is fictional. Impulse links force and time to a change in momentum.https://exercises.lol/video-media/ib_sports_science_hl/supported-focus-04/supported-focus-04.enzh.mp4?v=1793280656-2702026-10-29yes https://exercises.lol/videos/ib_sports_science_hl/supported-focus-062026-10-29https://exercises.lol/video-media/ib_sports_science_hl/supported-focus-06/supported-focus-06.thumb.jpg?v=1793280653InjuryThese are selected topics, not the whole syllabus, and every example is fictional. Compare injury rates per exposure, not raw counts.https://exercises.lol/video-media/ib_sports_science_hl/supported-focus-06/supported-focus-06.enzh.mp4?v=1793280653-2672026-10-29yes https://exercises.lol/videos/ib_sports_science_hl/supported-focus-072026-10-29https://exercises.lol/video-media/ib_sports_science_hl/supported-focus-07/supported-focus-07.thumb.jpg?v=1793280673Individual differencesThese are selected topics, not the whole syllabus, and every example is fictional. Stress depends on perceived demands against perceived resources.https://exercises.lol/video-media/ib_sports_science_hl/supported-focus-07/supported-focus-07.enzh.mp4?v=1793280673-2582026-10-29yes https://exercises.lol/videos/ib_sports_science_hl/supported-focus-082026-10-29https://exercises.lol/video-media/ib_sports_science_hl/supported-focus-08/supported-focus-08.thumb.jpg?v=1793280795Motor learningThese are selected topics, not the whole syllabus, and every example is fictional. Fast actions run open-loop; slower ones can use feedback, and only retention…https://exercises.lol/video-media/ib_sports_science_hl/supported-focus-08/supported-focus-08.enzh.mp4?v=1793280795-2962026-10-29yes https://exercises.lol/videos/ib_sports_science_hl/supported-focus-122026-10-29https://exercises.lol/video-media/ib_sports_science_hl/supported-focus-12/supported-focus-12.thumb.jpg?v=1793280782Experimental programmeThese are selected topics, not the whole syllabus, and every example is fictional. Every reading carries an uncertainty; random scatter averages out…https://exercises.lol/video-media/ib_sports_science_hl/supported-focus-12/supported-focus-12.enzh.mp4?v=1793280782-2632026-10-29yes https://exercises.lol/videos/ib_sports_science_sl/supported-focus-012026-10-29https://exercises.lol/video-media/ib_sports_science_sl/supported-focus-01/supported-focus-01.thumb.jpg?v=1793280837CommunicationThese are selected topics, not the whole syllabus, and every example is fictional. Cardiac output is heart rate times stroke volume, and it rises and recovers…https://exercises.lol/video-media/ib_sports_science_sl/supported-focus-01/supported-focus-01.enzh.mp4?v=1793280837-2672026-10-29yes https://exercises.lol/videos/ib_sports_science_sl/supported-focus-022026-10-29https://exercises.lol/video-media/ib_sports_science_sl/supported-focus-02/supported-focus-02.thumb.jpg?v=1793280952Hydration and nutritionThese are selected topics, not the whole syllabus, and every example is fictional. Sweat loss comes from a full water balance, not from the scale alone.…https://exercises.lol/video-media/ib_sports_science_sl/supported-focus-02/supported-focus-02.enzh.mp4?v=1793280952-2842026-10-29yes https://exercises.lol/videos/ib_sports_science_sl/supported-focus-042026-10-29https://exercises.lol/video-media/ib_sports_science_sl/supported-focus-04/supported-focus-04.thumb.jpg?v=1793280927Generating movement in the bodyThese are selected topics, not the whole syllabus, and every example is fictional. Impulse links force and time to a change in momentum.https://exercises.lol/video-media/ib_sports_science_sl/supported-focus-04/supported-focus-04.enzh.mp4?v=1793280927-2702026-10-29yes https://exercises.lol/videos/ib_sports_science_sl/supported-focus-062026-10-29https://exercises.lol/video-media/ib_sports_science_sl/supported-focus-06/supported-focus-06.thumb.jpg?v=1793292728InjuryThese are selected topics, not the whole syllabus, and every example is fictional. Compare injury rates per exposure, not raw counts.https://exercises.lol/video-media/ib_sports_science_sl/supported-focus-06/supported-focus-06.enzh.mp4?v=1793292728-2682026-10-29yes https://exercises.lol/videos/ib_sports_science_sl/supported-focus-072026-10-29https://exercises.lol/video-media/ib_sports_science_sl/supported-focus-07/supported-focus-07.thumb.jpg?v=1793281005Individual differencesThese are selected topics, not the whole syllabus, and every example is fictional. Stress depends on perceived demands against perceived resources.https://exercises.lol/video-media/ib_sports_science_sl/supported-focus-07/supported-focus-07.enzh.mp4?v=1793281005-2582026-10-29yes https://exercises.lol/videos/ib_sports_science_sl/supported-focus-082026-10-29https://exercises.lol/video-media/ib_sports_science_sl/supported-focus-08/supported-focus-08.thumb.jpg?v=1793281157Motor learningThese are selected topics, not the whole syllabus, and every example is fictional. Fast actions run open-loop; slower ones can use feedback, and only retention…https://exercises.lol/video-media/ib_sports_science_sl/supported-focus-08/supported-focus-08.enzh.mp4?v=1793281157-2962026-10-29yes https://exercises.lol/videos/ib_sports_science_sl/supported-focus-122026-10-29https://exercises.lol/video-media/ib_sports_science_sl/supported-focus-12/supported-focus-12.thumb.jpg?v=1793281139Experimental programmeThese are selected topics, not the whole syllabus, and every example is fictional. Every reading carries an uncertainty; random scatter averages out…https://exercises.lol/video-media/ib_sports_science_sl/supported-focus-12/supported-focus-12.enzh.mp4?v=1793281139-2632026-10-29yes https://exercises.lol/videos/ib_theatre_hl/topic-012026-10-29https://exercises.lol/video-media/ib_theatre_hl/topic-01/topic-01.thumb.jpg?v=1793281256Staging play textsThe production proposal goes from text to vision to document. Read the play as a theatre-maker, form one governing concept, and write a proposal the examiner…https://exercises.lol/video-media/ib_theatre_hl/topic-01/topic-01.enzh.mp4?v=1793281256-21632026-10-29yes https://exercises.lol/videos/ib_theatre_hl/topic-022026-10-29https://exercises.lol/video-media/ib_theatre_hl/topic-02/topic-02.thumb.jpg?v=1793281273World theatre traditionsThe research presentation is an individual, video-recorded presentation of 15 minutes at most, on an unfamiliar world theatre tradition. It needs academic and…https://exercises.lol/video-media/ib_theatre_hl/topic-02/topic-02.enzh.mp4?v=1793281273-21442026-10-29yes https://exercises.lol/videos/ib_theatre_hl/topic-032026-11-08https://exercises.lol/video-media/ib_theatre_hl/topic-03/topic-03.thumb.jpg?v=1794123724Collaborative original theatreWhy it matters. In 1970 the Paris company Théâtre du Soleil, led by Ariane Mnouchkine, made a play about the French Revolution called 1789. There was no script…https://exercises.lol/video-media/ib_theatre_hl/topic-03/topic-03.enzh.mp4?v=1794123724-25102026-10-29yes https://exercises.lol/videos/ib_theatre_hl/topic-042026-11-08https://exercises.lol/video-media/ib_theatre_hl/topic-04/topic-04.thumb.jpg?v=1794124295Performing theatre theoryWhy it matters. In 1949, in East Berlin, Bertolt Brecht's new company, the Berliner Ensemble, staged his play Mother Courage and Her Children. Mother Courage…https://exercises.lol/video-media/ib_theatre_hl/topic-04/topic-04.enzh.mp4?v=1794124295-25352026-10-29yes https://exercises.lol/videos/ib_theatre_sl/topic-012026-10-29https://exercises.lol/video-media/ib_theatre_sl/topic-01/topic-01.thumb.jpg?v=1793281469Staging play textsThe production proposal goes from text to vision to document. Read the play as a theatre-maker, form one governing concept, and write a proposal the examiner…https://exercises.lol/video-media/ib_theatre_sl/topic-01/topic-01.enzh.mp4?v=1793281469-21632026-10-29yes https://exercises.lol/videos/ib_theatre_sl/topic-022026-11-08https://exercises.lol/video-media/ib_theatre_sl/topic-02/topic-02.thumb.jpg?v=1794125192World theatre traditionsWhy it matters. In the spring of 1935 the Peking opera star Mei Lanfang toured the Soviet Union. In Moscow, according to Brecht, he gave a demonstration in an…https://exercises.lol/video-media/ib_theatre_sl/topic-02/topic-02.enzh.mp4?v=1794125192-26062026-10-29yes https://exercises.lol/videos/ib_theatre_sl/topic-032026-10-29https://exercises.lol/video-media/ib_theatre_sl/topic-03/topic-03.thumb.jpg?v=1793281987Collaborative original theatreCollaborative creation starts from a starting point, forms an intention, generates material through devising, and tests it in performance, then evaluates.https://exercises.lol/video-media/ib_theatre_sl/topic-03/topic-03.enzh.mp4?v=1793281987-21532026-10-29yes https://exercises.lol/videos/ib_tok/topic-012026-10-29https://exercises.lol/video-media/ib_tok/topic-01/topic-01.thumb.jpg?v=1793282665Knowledge and the knowerUntil August 2006 every school textbook said the Solar System had nine planets. Then the International Astronomical Union voted on a new definition: a planet…https://exercises.lol/video-media/ib_tok/topic-01/topic-01.enzh.mp4?v=1793282665-23792026-10-29yes https://exercises.lol/videos/ib_visual_arts_hl/session5-supported-preparation2026-10-30https://exercises.lol/video-media/ib_visual_arts_hl/session5-supported-preparation/session5-supported-preparation.thumb.jpg?v=1793324439Visual arts: analysis, development and curationFormal qualities include line, colour, form, space, composition and material. Explain relationships and possible effects before linking them to function and…https://exercises.lol/video-media/ib_visual_arts_hl/session5-supported-preparation/session5-supported-preparation.enzh.mp4?v=1793324439-24412026-10-28yes https://exercises.lol/videos/ib_visual_arts_sl/session5-supported-preparation2026-10-29https://exercises.lol/video-media/ib_visual_arts_sl/session5-supported-preparation/session5-supported-preparation.thumb.jpg?v=1793282191Visual arts: analysis, development and curationFormal qualities include line, colour, form, space, composition and material. Explain relationships and possible effects before linking them to function and…https://exercises.lol/video-media/ib_visual_arts_sl/session5-supported-preparation/session5-supported-preparation.enzh.mp4?v=1793282191-23382026-10-28yes https://exercises.lol/videos/ib_world_religions_sl/session5-supported-preparation2026-10-30https://exercises.lol/video-media/ib_world_religions_sl/session5-supported-preparation/session5-supported-preparation.thumb.jpg?v=1793333723World religions: respectful source inquiryBeliefs concern claims and understandings; practices concern actions; experiences concern what participants report living through. The relationships require…https://exercises.lol/video-media/ib_world_religions_sl/session5-supported-preparation/session5-supported-preparation.enzh.mp4?v=1793333723-23372026-10-28yes https://exercises.lol/videos/ielts/overview-and-preparation2026-10-28https://exercises.lol/video-media/ielts/overview-and-preparation/overview-and-preparation.thumb.jpg?v=1793189041IELTS Overview: Choices, Scores and PreparationImagine two learners who both want to study abroad. One course asks for a particular overall score and minimum scores in every skill. Another course may accept…https://exercises.lol/video-media/ielts/overview-and-preparation/overview-and-preparation.enzh.mp4?v=1793189041-210792026-10-02yes https://exercises.lol/videos/ielts/listening-evidence-and-answer-form2026-10-30https://exercises.lol/video-media/ielts/listening-evidence-and-answer-form/listening-evidence-and-answer-form.thumb.jpg?v=1793400204IELTS Listening: Evidence and Answer FormListening moves between everyday and study-related situations. A conversation about a visit requires you to distinguish a final booking from an earlier…https://exercises.lol/video-media/ielts/listening-evidence-and-answer-form/listening-evidence-and-answer-form.enzh.mp4?v=1793400204-215732026-10-02yes https://exercises.lol/videos/ielts/reading-text-evidence-and-worked-decisions2026-10-28https://exercises.lol/video-media/ielts/reading-text-evidence-and-worked-decisions/reading-text-evidence-and-worked-decisions.thumb.jpg?v=1793202879IELTS Reading: Text Evidence and Worked DecisionsThe original Reading notes introduce the complete test clock and the difference between skimming and scanning. Skimming helps locate the shape of a text.…https://exercises.lol/video-media/ielts/reading-text-evidence-and-worked-decisions/reading-text-evidence-and-worked-decisions.enzh.mp4?v=1793202879-214702026-10-02yes https://exercises.lol/videos/ielts/writing-reports-essays-and-revisions2026-10-30https://exercises.lol/video-media/ielts/writing-reports-essays-and-revisions/writing-reports-essays-and-revisions.thumb.jpg?v=1793394450IELTS Writing: Reports, Essays and RevisionsThe existing notes introduce the test clock and four criteria. Task achievement applies to the visual report, while task response applies to the essay.…https://exercises.lol/video-media/ielts/writing-reports-essays-and-revisions/writing-reports-essays-and-revisions.enzh.mp4?v=1793394450-216842026-10-02yes https://exercises.lol/videos/ielts/speaking-exchanges-long-turns-and-pronunciation2026-10-30https://exercises.lol/video-media/ielts/speaking-exchanges-long-turns-and-pronunciation/speaking-exchanges-long-turns-and-pronunciation.thumb.jpg?v=1793392713IELTS Speaking: Exchanges, Long Turns and PronunciationThe original handout introduces the four criteria. Fluency and coherence concern continuing at a useful pace with connected ideas. Vocabulary includes finding…https://exercises.lol/video-media/ielts/speaking-exchanges-long-turns-and-pronunciation/speaking-exchanges-long-turns-and-pronunciation.enzh.mp4?v=1793392713-213832026-10-02yes https://exercises.lol/videos/igcse_biology/classification2026-10-28https://exercises.lol/video-media/igcse_biology/classification/classification.thumb.jpg?v=1793226412Characteristics & ClassificationA car moves. It uses fuel, gives off waste gases, and responds when you turn the wheel. So is a car alive? No — and biology can tell you exactly why. Living…https://exercises.lol/video-media/igcse_biology/classification/classification.enzh.mp4?v=1793226412-29022026-08-15yes https://exercises.lol/videos/igcse_biology/cells2026-10-30https://exercises.lol/video-media/igcse_biology/cells/cells.thumb.jpg?v=1793375386Cell StructureZoom in on a leaf, on your skin, on a drop of pond water — and you find the same thing everywhere: cells. A cell is the smallest thing that can carry out all…https://exercises.lol/video-media/igcse_biology/cells/cells.enzh.mp4?v=1793375386-28202026-08-15yes https://exercises.lol/videos/igcse_biology/transport-in-cells2026-10-28https://exercises.lol/video-media/igcse_biology/transport-in-cells/transport-in-cells.thumb.jpg?v=1793215043Movement Into and Out of CellsA cell is surrounded by a membrane, and it must keep trading with the world outside. Oxygen has to get in. Carbon dioxide has to get out. Water moves both…https://exercises.lol/video-media/igcse_biology/transport-in-cells/transport-in-cells.enzh.mp4?v=1793215043-24642026-08-15yes https://exercises.lol/videos/igcse_biology/biological-molecules2026-10-29https://exercises.lol/video-media/igcse_biology/biological-molecules/biological-molecules.thumb.jpg?v=1793305077Biological MoleculesBread, meat, oil, your own muscles — all of them are built from just a handful of chemical elements. And the large molecules in your food are not really large…https://exercises.lol/video-media/igcse_biology/biological-molecules/biological-molecules.enzh.mp4?v=1793305077-23252026-08-15yes https://exercises.lol/videos/igcse_biology/enzymes2026-10-30https://exercises.lol/video-media/igcse_biology/enzymes/enzymes.thumb.jpg?v=1793332350EnzymesEvery second, thousands of chemical reactions are running inside you. Left to themselves, almost all of them would be far too slow to keep you alive. What…https://exercises.lol/video-media/igcse_biology/enzymes/enzymes.enzh.mp4?v=1793332350-23542026-08-15yes https://exercises.lol/videos/igcse_biology/photosynthesis2026-10-30https://exercises.lol/video-media/igcse_biology/photosynthesis/photosynthesis.thumb.jpg?v=1793329335PhotosynthesisA plant cannot hunt and it cannot move. So it builds its own food out of almost nothing: a gas from the air, water from the soil, and light. Every meal you…https://exercises.lol/video-media/igcse_biology/photosynthesis/photosynthesis.enzh.mp4?v=1793329335-24552026-08-15yes https://exercises.lol/videos/igcse_biology/human-nutrition2026-10-31https://exercises.lol/video-media/igcse_biology/human-nutrition/human-nutrition.thumb.jpg?v=1793406950Human NutritionThe food on your plate is made of molecules far too big to enter your blood. So your body takes it apart — first by crushing it, then by cutting the molecules…https://exercises.lol/video-media/igcse_biology/human-nutrition/human-nutrition.enzh.mp4?v=1793406950-29522026-08-15yes https://exercises.lol/videos/igcse_biology/transport-in-plants2026-10-29https://exercises.lol/video-media/igcse_biology/transport-in-plants/transport-in-plants.thumb.jpg?v=1793306283Transport in PlantsA tall tree lifts water a hundred metres into the air, every day, with no pump and no moving parts. It does it using nothing but evaporation from its leaves…https://exercises.lol/video-media/igcse_biology/transport-in-plants/transport-in-plants.enzh.mp4?v=1793306283-23542026-08-15yes https://exercises.lol/videos/igcse_biology/circulation2026-10-30https://exercises.lol/video-media/igcse_biology/circulation/circulation.thumb.jpg?v=1793367794Transport in AnimalsYour heart beats about a hundred thousand times a day, and it has never once stopped to rest. It is not really one pump — it is two, side by side, sharing a…https://exercises.lol/video-media/igcse_biology/circulation/circulation.enzh.mp4?v=1793367794-25012026-08-15yes https://exercises.lol/videos/igcse_biology/disease-immunity2026-10-31https://exercises.lol/video-media/igcse_biology/disease-immunity/disease-immunity.thumb.jpg?v=1793407747Diseases and ImmunityRight now, your body is being tested by microbes — on your skin, in the air you breathe, in the food you eat. Almost all of them never get in. And when one…https://exercises.lol/video-media/igcse_biology/disease-immunity/disease-immunity.enzh.mp4?v=1793407747-23642026-08-15yes https://exercises.lol/videos/igcse_biology/gas-exchange2026-10-29https://exercises.lol/video-media/igcse_biology/gas-exchange/gas-exchange.thumb.jpg?v=1793306384Gas Exchange in HumansYour lungs would cover half a tennis court if you spread them flat. They are not one big bag — they are millions of tiny sacs, and that is the whole point.…https://exercises.lol/video-media/igcse_biology/gas-exchange/gas-exchange.enzh.mp4?v=1793306384-23532026-08-15yes https://exercises.lol/videos/igcse_biology/respiration2026-10-28https://exercises.lol/video-media/igcse_biology/respiration/respiration.thumb.jpg?v=1793189847RespirationHere is the single most common mix-up in IGCSE Biology. Respiration is not breathing. Breathing is moving air in and out of your lungs — a physical action…https://exercises.lol/video-media/igcse_biology/respiration/respiration.enzh.mp4?v=1793189847-22992026-08-15yes https://exercises.lol/videos/igcse_biology/excretion2026-10-31https://exercises.lol/video-media/igcse_biology/excretion/excretion.thumb.jpg?v=1793408487Excretion in HumansYour kidneys filter your entire blood supply about thirty times a day. But here is the clever part: they do not pick out the rubbish. They throw almost…https://exercises.lol/video-media/igcse_biology/excretion/excretion.enzh.mp4?v=1793408487-22902026-08-15yes https://exercises.lol/videos/igcse_biology/coordination2026-10-31https://exercises.lol/video-media/igcse_biology/coordination/coordination.thumb.jpg?v=1793411480Coordination and ResponseTouch something hot and your hand is already moving before you feel the pain. That is one of your two control systems — the fast one, made of nerves. The other…https://exercises.lol/video-media/igcse_biology/coordination/coordination.enzh.mp4?v=1793411480-210932026-08-15yes https://exercises.lol/videos/igcse_biology/drugs2026-10-29https://exercises.lol/video-media/igcse_biology/drugs/drugs.thumb.jpg?v=1793297051Drugs and AntibioticsAsk a doctor for antibiotics when you have a cold and they will say no. Not because they are being difficult — because it genuinely would not work, and because…https://exercises.lol/video-media/igcse_biology/drugs/drugs.enzh.mp4?v=1793297051-22762026-08-15yes https://exercises.lol/videos/igcse_biology/reproduction2026-10-28https://exercises.lol/video-media/igcse_biology/reproduction/reproduction.thumb.jpg?v=1793220578ReproductionThere are only two ways to make a new organism, and they trade off against each other. One is fast, needs a single parent, and makes perfect copies. The other…https://exercises.lol/video-media/igcse_biology/reproduction/reproduction.enzh.mp4?v=1793220578-26422026-08-15yes https://exercises.lol/videos/igcse_biology/inheritance2026-10-30https://exercises.lol/video-media/igcse_biology/inheritance/inheritance.thumb.jpg?v=1793330488InheritanceTwo brown-eyed parents can have a blue-eyed child. That is not a mistake, and it is not a surprise once you can read genotypes. By the end of this lesson you…https://exercises.lol/video-media/igcse_biology/inheritance/inheritance.enzh.mp4?v=1793330488-24902026-08-15yes https://exercises.lol/videos/igcse_biology/variation-selection2026-10-28https://exercises.lol/video-media/igcse_biology/variation-selection/variation-selection.thumb.jpg?v=1793206453Variation and selectionIn the year eighteen hundred, almost every peppered moth in England was pale. Fifty years later, in the smoky cities, almost every one was black. No moth…https://exercises.lol/video-media/igcse_biology/variation-selection/variation-selection.enzh.mp4?v=1793206453-24552026-08-15yes https://exercises.lol/videos/igcse_biology/organisms-and-their-environment2026-10-28https://exercises.lol/video-media/igcse_biology/organisms-and-their-environment/organisms-and-their-environment.thumb.jpg?v=1793183121Organisms and their EnvironmentAn African savanna. A coral reef. They look nothing alike, but they run on the same rule. Every living thing here is joined to the others by feeding. Energy…https://exercises.lol/video-media/igcse_biology/organisms-and-their-environment/organisms-and-their-environment.enzh.mp4?v=1793183121-24912026-08-15yes https://exercises.lol/videos/igcse_biology/human-influences-on-ecosystems2026-10-29https://exercises.lol/video-media/igcse_biology/human-influences-on-ecosystems/human-influences-on-ecosystems.thumb.jpg?v=1793306673Human influences on ecosystemsA farmer spreads fertiliser on a field. Ordinary, useful work. Two kilometres away there is a river, full of fish. Three weeks later those fish are floating…https://exercises.lol/video-media/igcse_biology/human-influences-on-ecosystems/human-influences-on-ecosystems.enzh.mp4?v=1793306673-24632026-08-15yes https://exercises.lol/videos/igcse_biology/biotechnology-and-genetic-modification2026-10-30https://exercises.lol/video-media/igcse_biology/biotechnology-and-genetic-modification/biotechnology-and-genetic-modification.thumb.jpg?v=1793367232Biotechnology and genetic modificationSteel tanks, warm and gently stirred. Inside tanks like these, billions of living microbes are working for us — making penicillin, a protein food called…https://exercises.lol/video-media/igcse_biology/biotechnology-and-genetic-modification/biotechnology-and-genetic-modification.enzh.mp4?v=1793367232-24782026-08-15yes https://exercises.lol/videos/igcse_business_studies/understanding-business-activity2026-10-29https://exercises.lol/video-media/igcse_business_studies/understanding-business-activity/understanding-business-activity.thumb.jpg?v=1793305953Understanding business activityLook at any high street. Shop after shop, all selling something, all chasing the same customers. Every one of them is a business. But what is a business really…https://exercises.lol/video-media/igcse_business_studies/understanding-business-activity/understanding-business-activity.enzh.mp4?v=1793305953-210702026-08-15yes https://exercises.lol/videos/igcse_business_studies/people-in-business2026-10-30https://exercises.lol/video-media/igcse_business_studies/people-in-business/people-in-business.thumb.jpg?v=1793348838People in businessLook at this factory floor. Hundreds of people, side by side, each doing a small part of one job. Every one of them had to be found, trained, paid — and given…https://exercises.lol/video-media/igcse_business_studies/people-in-business/people-in-business.enzh.mp4?v=1793348838-27912026-08-15yes https://exercises.lol/videos/igcse_business_studies/marketing2026-10-31https://exercises.lol/video-media/igcse_business_studies/marketing/marketing.thumb.jpg?v=1793406368MarketingCount the messages in this one street. Screens, posters, logos — every one of them is a business trying to reach you. But adverts are only the last step. Long…https://exercises.lol/video-media/igcse_business_studies/marketing/marketing.enzh.mp4?v=1793406368-25482026-08-15yes https://exercises.lol/videos/igcse_business_studies/operations-management2026-10-30https://exercises.lol/video-media/igcse_business_studies/operations-management/operations-management.thumb.jpg?v=1793403706Operations managementLook inside a car factory. The same car, again and again, hundreds every day, each one exactly like the last. Somebody decided all of it: how to make it, what…https://exercises.lol/video-media/igcse_business_studies/operations-management/operations-management.enzh.mp4?v=1793403706-25872026-08-15yes https://exercises.lol/videos/igcse_business_studies/financial-information-and-decisions2026-11-04https://exercises.lol/video-media/igcse_business_studies/financial-information-and-decisions/financial-information-and-decisions.thumb.jpg?v=1793789426Financial information and decisionsThis business was doing well. Every month it made a profit — the products sold, the customers were happy. But watch the money in the bank. Suppliers wanted…https://exercises.lol/video-media/igcse_business_studies/financial-information-and-decisions/financial-information-and-decisions.enzh.mp4?v=1793789426-27722026-08-15yes https://exercises.lol/videos/igcse_business_studies/external-influences-on-business2026-11-04https://exercises.lol/video-media/igcse_business_studies/external-influences-on-business/external-influences-on-business.thumb.jpg?v=1793789381External influences on business activityThis building is not a business. Nobody inside it sells anything. But the people in there can raise a tax, change a law, or push interest rates up — and every…https://exercises.lol/video-media/igcse_business_studies/external-influences-on-business/external-influences-on-business.enzh.mp4?v=1793789381-25032026-08-15yes https://exercises.lol/videos/igcse_chemistry/states-of-matter2026-10-31https://exercises.lol/video-media/igcse_chemistry/states-of-matter/states-of-matter.thumb.jpg?v=1793409175States of MatterSit in a room while someone makes coffee next door. Soon you can smell it, even from across the room. How? Everything around you is made of tiny particles, far…https://exercises.lol/video-media/igcse_chemistry/states-of-matter/states-of-matter.enzh.mp4?v=1793409175-28122026-08-15yes https://exercises.lol/videos/igcse_chemistry/atoms-bonding2026-10-30https://exercises.lol/video-media/igcse_chemistry/atoms-bonding/atoms-bonding.thumb.jpg?v=1793324229Atoms & BondingLook at these two things. A diamond — the hardest material you can buy. And the soft, grey lead in a pencil. They could not seem more different. Yet both are…https://exercises.lol/video-media/igcse_chemistry/atoms-bonding/atoms-bonding.enzh.mp4?v=1793324229-210062026-08-15yes https://exercises.lol/videos/igcse_chemistry/stoichiometry2026-10-30https://exercises.lol/video-media/igcse_chemistry/stoichiometry/stoichiometry.thumb.jpg?v=1793403177StoichiometryHere is a chemist's problem. A single atom is far too small to see, and there are billions upon billions in the tiniest speck. So how do you count them? You…https://exercises.lol/video-media/igcse_chemistry/stoichiometry/stoichiometry.enzh.mp4?v=1793403177-29322026-08-15yes https://exercises.lol/videos/igcse_chemistry/electrolysis2026-10-30https://exercises.lol/video-media/igcse_chemistry/electrolysis/electrolysis.thumb.jpg?v=1793352892ElectrolysisElectricity can do something amazing: it can tear a compound apart. Pass a current through a melted or dissolved compound, and it splits into its elements.…https://exercises.lol/video-media/igcse_chemistry/electrolysis/electrolysis.enzh.mp4?v=1793352892-26242026-08-15yes https://exercises.lol/videos/igcse_chemistry/energetics2026-10-29https://exercises.lol/video-media/igcse_chemistry/energetics/energetics.thumb.jpg?v=1793256160EnergeticsSnap a glow stick, and it lights up. Hold a hand-warmer, and it gets hot. Open an instant cold pack, and it turns icy. In every case, a chemical reaction is…https://exercises.lol/video-media/igcse_chemistry/energetics/energetics.enzh.mp4?v=1793256160-23502026-08-15yes https://exercises.lol/videos/igcse_chemistry/rates-equilibrium2026-10-29https://exercises.lol/video-media/igcse_chemistry/rates-equilibrium/rates-equilibrium.thumb.jpg?v=1793294084Rates & EquilibriumMilk on the counter spoils in a day. In the fridge, it lasts a week. Same milk — but the reaction runs at a different speed. First, a quick check: a chemical…https://exercises.lol/video-media/igcse_chemistry/rates-equilibrium/rates-equilibrium.enzh.mp4?v=1793294084-29532026-08-15yes https://exercises.lol/videos/igcse_chemistry/acids-bases-salts2026-10-30https://exercises.lol/video-media/igcse_chemistry/acids-bases-salts/acids-bases-salts.thumb.jpg?v=1793375439Acids, Bases & SaltsLemon juice, vinegar, and the acid in your stomach — acids are everywhere. So are their opposites: alkalis, like soap and oven cleaner. Mix an acid and an…https://exercises.lol/video-media/igcse_chemistry/acids-bases-salts/acids-bases-salts.enzh.mp4?v=1793375439-27862026-08-15yes https://exercises.lol/videos/igcse_chemistry/periodic-table2026-10-29https://exercises.lol/video-media/igcse_chemistry/periodic-table/periodic-table.thumb.jpg?v=1793299116The Periodic TableThis is the most powerful chart in all of chemistry: the Periodic Table. It looks like a jumble of boxes, but it hides a beautiful secret. The elements are…https://exercises.lol/video-media/igcse_chemistry/periodic-table/periodic-table.enzh.mp4?v=1793299116-26742026-08-15yes https://exercises.lol/videos/igcse_chemistry/metals2026-10-29https://exercises.lol/video-media/igcse_chemistry/metals/metals.thumb.jpg?v=1793298408MetalsWhy do we dig gold out of the ground as shiny nuggets, but iron only as dull, rusty rock? And why does a soda can never rust, while an iron nail does? The…https://exercises.lol/video-media/igcse_chemistry/metals/metals.enzh.mp4?v=1793298408-28222026-08-15yes https://exercises.lol/videos/igcse_chemistry/environment2026-11-04https://exercises.lol/video-media/igcse_chemistry/environment/environment.thumb.jpg?v=1793790744Chemistry of the EnvironmentLook at a glass of water, and the air in this room. Both look clean and simple. But natural water carries dissolved oxygen, minerals, and sometimes sewage and…https://exercises.lol/video-media/igcse_chemistry/environment/environment.enzh.mp4?v=1793790744-26402026-08-15yes https://exercises.lol/videos/igcse_chemistry/organic2026-10-28https://exercises.lol/video-media/igcse_chemistry/organic/organic.thumb.jpg?v=1793221962Organic ChemistryPetrol, plastic bottles, vinegar, alcohol, and the proteins in your body. They seem completely unrelated. But every one of them is built from carbon. Carbon is…https://exercises.lol/video-media/igcse_chemistry/organic/organic.enzh.mp4?v=1793221962-210102026-08-15yes https://exercises.lol/videos/igcse_chemistry/experimental2026-10-29https://exercises.lol/video-media/igcse_chemistry/experimental/experimental.thumb.jpg?v=1793299950Experimental TechniquesYou are handed an unknown white powder and a colourless solution. No labels. How do you find out what they are? Chemistry gives you a detective's toolkit: add…https://exercises.lol/video-media/igcse_chemistry/experimental/experimental.enzh.mp4?v=1793299950-28062026-08-15yes https://exercises.lol/videos/igcse_computer_science/binary2026-10-28https://exercises.lol/video-media/igcse_computer_science/binary/binary.thumb.jpg?v=1793191346Why Computers Use BinaryInside a processor there are billions of tiny switches. Each one can only be on, or off. That is all a computer physically has — no threes, no sevens, no…https://exercises.lol/video-media/igcse_computer_science/binary/binary.enzh.mp4?v=1793191346-212752026-08-15yes https://exercises.lol/videos/igcse_computer_science/data-transmission2026-10-31https://exercises.lol/video-media/igcse_computer_science/data-transmission/data-transmission.thumb.jpg?v=1793406383Data TransmissionYou send a photo to a friend on the other side of the world. It does not travel as one lump. It is chopped into hundreds of small packets, each one labelled…https://exercises.lol/video-media/igcse_computer_science/data-transmission/data-transmission.enzh.mp4?v=1793406383-26562026-08-15yes https://exercises.lol/videos/igcse_computer_science/cpu2026-10-29https://exercises.lol/video-media/igcse_computer_science/cpu/cpu.thumb.jpg?v=1793264139The CPUThe processor in your phone is doing something almost stupidly simple. Fetch one instruction. Work out what it means. Do it. Then fetch the next one. That is…https://exercises.lol/video-media/igcse_computer_science/cpu/cpu.enzh.mp4?v=1793264139-210882026-08-15yes https://exercises.lol/videos/igcse_computer_science/hardware-software2026-10-28https://exercises.lol/video-media/igcse_computer_science/hardware-software/hardware-software.thumb.jpg?v=1793181927Hardware & SoftwareHere is a brand new computer. Every physical part works — the processor, the memory, the screen, the keyboard. Switch it on, and nothing happens. No desktop…https://exercises.lol/video-media/igcse_computer_science/hardware-software/hardware-software.enzh.mp4?v=1793181927-27902026-08-15yes https://exercises.lol/videos/igcse_computer_science/internet-web2026-10-30https://exercises.lol/video-media/igcse_computer_science/internet-web/internet-web.thumb.jpg?v=1793403837The Internet & the WebYou type a web address and press enter. Less than a second later, a page appears — a page that lives on a computer maybe ten thousand kilometres away. In that…https://exercises.lol/video-media/igcse_computer_science/internet-web/internet-web.enzh.mp4?v=1793403837-25922026-08-15yes https://exercises.lol/videos/igcse_computer_science/automated-systems2026-10-30https://exercises.lol/video-media/igcse_computer_science/automated-systems/automated-systems.thumb.jpg?v=1793338259Automated SystemsPicture a greenhouse at three in the morning. Nobody is there. The air warms up a little, and a window slides open all by itself. An hour later it closes…https://exercises.lol/video-media/igcse_computer_science/automated-systems/automated-systems.enzh.mp4?v=1793338259-26212026-08-15yes https://exercises.lol/videos/igcse_computer_science/program-development-life-cycle2026-10-28https://exercises.lol/video-media/igcse_computer_science/program-development-life-cycle/program-development-life-cycle.thumb.jpg?v=1793174449The Program Development Life CycleEvery app on your phone was written by someone like this. But they did not start by typing code. Before the first line, the problem was studied, the solution…https://exercises.lol/video-media/igcse_computer_science/program-development-life-cycle/program-development-life-cycle.enzh.mp4?v=1793174449-25562026-08-15yes https://exercises.lol/videos/igcse_computer_science/programming2026-10-29https://exercises.lol/video-media/igcse_computer_science/programming/programming.thumb.jpg?v=1793307312ProgrammingHere is a short program. It reads five test marks and prints the total. The five marks are eight, nine, seven, six and ten, so the total should be forty. Watch…https://exercises.lol/video-media/igcse_computer_science/programming/programming.enzh.mp4?v=1793307312-27902026-08-15yes https://exercises.lol/videos/igcse_computer_science/databases2026-10-29https://exercises.lol/video-media/igcse_computer_science/databases/databases.thumb.jpg?v=1793311506DatabasesBefore computers, a library kept a drawer like this. One card per book, each holding the same few facts, all kept in order — so a librarian could find any book…https://exercises.lol/video-media/igcse_computer_science/databases/databases.enzh.mp4?v=1793311506-25002026-08-15yes https://exercises.lol/videos/igcse_computer_science/boolean-logic2026-10-31https://exercises.lol/video-media/igcse_computer_science/boolean-logic/boolean-logic.thumb.jpg?v=1793408784Boolean LogicLook closely at this chip. There is nothing clever inside it. It cannot think. Inside are millions of tiny switches, and each switch can only be one of two…https://exercises.lol/video-media/igcse_computer_science/boolean-logic/boolean-logic.enzh.mp4?v=1793408784-25122026-08-15yes https://exercises.lol/videos/igcse_economics/basic-economic-problem2026-10-27https://exercises.lol/video-media/igcse_economics/basic-economic-problem/basic-economic-problem.thumb.jpg?v=1793136802The Basic Economic ProblemYou have ten dollars. In front of you there is a book you want and a game you want. You want both. You can only have one. So you pick the book — and the moment…https://exercises.lol/video-media/igcse_economics/basic-economic-problem/basic-economic-problem.enzh.mp4?v=1793136802-25542026-08-15yes https://exercises.lol/videos/igcse_economics/allocation-of-resources2026-10-30https://exercises.lol/video-media/igcse_economics/allocation-of-resources/allocation-of-resources.thumb.jpg?v=1793319205The Allocation of ResourcesNobody in the world is in charge of deciding how many coffee beans to grow. No committee meets. No plan is written. And yet, most mornings, there is coffee.…https://exercises.lol/video-media/igcse_economics/allocation-of-resources/allocation-of-resources.enzh.mp4?v=1793319205-213112026-08-15yes https://exercises.lol/videos/igcse_economics/microeconomic-decision-makers2026-10-29https://exercises.lol/video-media/igcse_economics/microeconomic-decision-makers/microeconomic-decision-makers.thumb.jpg?v=1793310748Microeconomic Decision-MakersYou have a fish. You want a pair of shoes. Long ago that meant barter — swapping goods directly. And to do it, you need to find someone who has shoes, and who…https://exercises.lol/video-media/igcse_economics/microeconomic-decision-makers/microeconomic-decision-makers.enzh.mp4?v=1793310748-27602026-08-15yes https://exercises.lol/videos/igcse_economics/government-and-the-macroeconomy2026-10-30https://exercises.lol/video-media/igcse_economics/government-and-the-macroeconomy/government-and-the-macroeconomy.thumb.jpg?v=1793404526Government and the MacroeconomyImagine you are the government. You want the economy to grow faster. So you spend more, firms hire, and unemployment falls. Excellent. Then prices start…https://exercises.lol/video-media/igcse_economics/government-and-the-macroeconomy/government-and-the-macroeconomy.enzh.mp4?v=1793404526-27272026-08-15yes https://exercises.lol/videos/igcse_economics/economic-development2026-10-29https://exercises.lol/video-media/igcse_economics/economic-development/economic-development.thumb.jpg?v=1793259123Economic developmentTwo babies are born on the same morning. One in a rich country, one in a poor country. Neither of them chose where. Yet one will probably live many years…https://exercises.lol/video-media/igcse_economics/economic-development/economic-development.enzh.mp4?v=1793259123-25232026-08-15yes https://exercises.lol/videos/igcse_economics/international-trade-and-globalisation2026-10-31https://exercises.lol/video-media/igcse_economics/international-trade-and-globalisation/international-trade-and-globalisation.thumb.jpg?v=1793407101International trade and globalisationLook around your room. The phone in your hand, the coffee in your cup, the clothes you are wearing — almost none of it was made here. It came by sea, in steel…https://exercises.lol/video-media/igcse_economics/international-trade-and-globalisation/international-trade-and-globalisation.enzh.mp4?v=1793407101-25402026-08-15yes https://exercises.lol/videos/igcse_english/reading-skills2026-10-28https://exercises.lol/video-media/igcse_english/reading-skills/reading-skills.thumb.jpg?v=1793181273Reading SkillsOpen the reading paper. You see a long text — six hundred words, maybe more — and a full page of questions. The clock says forty-five minutes. Many students…https://exercises.lol/video-media/igcse_english/reading-skills/reading-skills.enzh.mp4?v=1793181273-24752026-08-15yes https://exercises.lol/videos/igcse_english/purpose-audience-accuracy2026-10-30https://exercises.lol/video-media/igcse_english/purpose-audience-accuracy/purpose-audience-accuracy.thumb.jpg?v=1793344904Writing: Purpose, Audience and AccuracyTwo students want the same thing: permission to use the school hall on Saturday. Both write to the head teacher. The first one says: <slow>Hi, can we have the…https://exercises.lol/video-media/igcse_english/purpose-audience-accuracy/purpose-audience-accuracy.enzh.mp4?v=1793344904-24702026-08-15yes https://exercises.lol/videos/igcse_english/informal-email2026-10-29https://exercises.lol/video-media/igcse_english/informal-email/informal-email.thumb.jpg?v=1793268979Writing an Informal EmailTwo students answer the same task: write to your friend about a place you visited. Here is the first one. <slow>I visited a museum. It was good. I went with my…https://exercises.lol/video-media/igcse_english/informal-email/informal-email.enzh.mp4?v=1793268979-24692026-08-15yes https://exercises.lol/videos/igcse_english/formal-letter2026-10-29https://exercises.lol/video-media/igcse_english/formal-letter/formal-letter.thumb.jpg?v=1793305895Writing a Formal Letter or EmailA student finds that the new bus timetable makes her late for school every morning. She decides to write to the bus company. Her first draft says: <slow>This…https://exercises.lol/video-media/igcse_english/formal-letter/formal-letter.enzh.mp4?v=1793305895-24842026-08-15yes https://exercises.lol/videos/igcse_english/report2026-10-29https://exercises.lol/video-media/igcse_english/report/report.thumb.jpg?v=1793305830Writing a ReportA club leader has to decide whether to run the school trip again next year. Two students send her an account of it. The first says: <slow>The trip was amazing!…https://exercises.lol/video-media/igcse_english/report/report.enzh.mp4?v=1793305830-24692026-08-15yes https://exercises.lol/videos/igcse_english/article2026-10-29https://exercises.lol/video-media/igcse_english/article/article.thumb.jpg?v=1793297083Writing an ArticleTwo students write an article about sleep for the school magazine. Here is one opening: <slow>Sleep is very important for students. In this article I will…https://exercises.lol/video-media/igcse_english/article/article.enzh.mp4?v=1793297083-24692026-08-15yes https://exercises.lol/videos/igcse_english/review2026-10-30https://exercises.lol/video-media/igcse_english/review/review.thumb.jpg?v=1793348874Writing a ReviewYou are deciding where to eat, and you read two reviews of the same restaurant. The first review says: <slow>The food was nice and the staff were nice. I liked…https://exercises.lol/video-media/igcse_english/review/review.enzh.mp4?v=1793348874-24572026-08-15yes https://exercises.lol/videos/igcse_english/essay2026-10-30https://exercises.lol/video-media/igcse_english/essay/essay.thumb.jpg?v=1793345561Writing an EssayTwo students answer the same essay question: should students have homework? Here is the first one. Homework is good. It helps you learn. Also some students do…https://exercises.lol/video-media/igcse_english/essay/essay.enzh.mp4?v=1793345561-24752026-08-15yes https://exercises.lol/videos/igcse_english/listening2026-10-29https://exercises.lol/video-media/igcse_english/listening/listening.thumb.jpg?v=1793318063Listening SkillsHere is what makes listening different from every other paper. In reading, the text sits still and waits for you. In listening, <slow>the recording does not…https://exercises.lol/video-media/igcse_english/listening/listening.enzh.mp4?v=1793318063-24192026-08-15yes https://exercises.lol/videos/igcse_english/speaking-skills2026-10-30https://exercises.lol/video-media/igcse_english/speaking-skills/speaking-skills.thumb.jpg?v=1793331285Speaking skillsTen minutes. Two people. One conversation, in English. That is the whole speaking test — no essay, no grammar paper. You just talk. So why do so many good…https://exercises.lol/video-media/igcse_english/speaking-skills/speaking-skills.enzh.mp4?v=1793331285-24352026-08-15yes https://exercises.lol/videos/igcse_english/vocabulary-and-text-types2026-10-29https://exercises.lol/video-media/igcse_english/vocabulary-and-text-types/vocabulary-and-text-types.thumb.jpg?v=1793292858Vocabulary and Text TypesTwo students get the same task: a report for the head teacher about the school trip. The first student writes: Hi Sir! The trip was good. The food was good and…https://exercises.lol/video-media/igcse_english/vocabulary-and-text-types/vocabulary-and-text-types.enzh.mp4?v=1793292858-24442026-08-15yes https://exercises.lol/videos/igcse_mathematics/number2026-10-30https://exercises.lol/video-media/igcse_mathematics/number/number.thumb.jpg?v=1793334446NumberTwo buses leave the same stop at nine o'clock. One runs every twelve minutes, the other every eighteen. When do they next leave together? Not at thirty…https://exercises.lol/video-media/igcse_mathematics/number/number.enzh.mp4?v=1793334446-218482026-08-15yes https://exercises.lol/videos/igcse_mathematics/algebra-and-graphs2026-10-29https://exercises.lol/video-media/igcse_mathematics/algebra-and-graphs/algebra-and-graphs.thumb.jpg?v=1793315157Algebra and graphsLook at the main cable of this bridge. That curve is not an accident. Every cable like it hangs in the same shape, and one short rule describes every point on…https://exercises.lol/video-media/igcse_mathematics/algebra-and-graphs/algebra-and-graphs.enzh.mp4?v=1793315157-211772026-08-15yes https://exercises.lol/videos/igcse_mathematics/coordinate-geometry2026-10-30https://exercises.lol/video-media/igcse_mathematics/coordinate-geometry/coordinate-geometry.thumb.jpg?v=1793324023Coordinate geometryLook down on a city like this and every street corner has an address: so many blocks across, so many blocks up. Two numbers, and you know exactly where you…https://exercises.lol/video-media/igcse_mathematics/coordinate-geometry/coordinate-geometry.enzh.mp4?v=1793324023-24542026-08-15yes https://exercises.lol/videos/igcse_mathematics/geometry2026-10-30https://exercises.lol/video-media/igcse_mathematics/geometry/geometry.thumb.jpg?v=1793349621GeometryLook closely at a honeycomb. Every cell is a hexagon — six straight sides, all the same. Not squares. Not pentagons. Hexagons. Bees never studied geometry, but…https://exercises.lol/video-media/igcse_mathematics/geometry/geometry.enzh.mp4?v=1793349621-28042026-08-15yes https://exercises.lol/videos/igcse_mathematics/mensuration2026-10-29https://exercises.lol/video-media/igcse_mathematics/mensuration/mensuration.thumb.jpg?v=1793316199MensurationThe Great Pyramid of Giza has stood for four and a half thousand years. How much stone is inside it? About two and a half million cubic metres — and one…https://exercises.lol/video-media/igcse_mathematics/mensuration/mensuration.enzh.mp4?v=1793316199-24672026-08-15yes https://exercises.lol/videos/igcse_mathematics/trigonometry2026-10-27https://exercises.lol/video-media/igcse_mathematics/trigonometry/trigonometry.thumb.jpg?v=1793139268TrigonometryHow tall is that tower? You cannot climb it with a tape measure. But you can stand on the ground, walk fifty metres back, and measure one angle — the angle you…https://exercises.lol/video-media/igcse_mathematics/trigonometry/trigonometry.enzh.mp4?v=1793139268-25172026-08-15yes https://exercises.lol/videos/igcse_mathematics/transformations-and-vectors2026-10-29https://exercises.lol/video-media/igcse_mathematics/transformations-and-vectors/transformations-and-vectors.thumb.jpg?v=1793306773Transformations and vectorsLook at this wall. It seems complicated — hundreds of shapes locking together. But nobody drew every piece. Someone drew one small shape, then moved it again…https://exercises.lol/video-media/igcse_mathematics/transformations-and-vectors/transformations-and-vectors.enzh.mp4?v=1793306773-24762026-08-15yes https://exercises.lol/videos/igcse_mathematics/probability2026-10-29https://exercises.lol/video-media/igcse_mathematics/probability/probability.thumb.jpg?v=1793313847ProbabilityWill it rain tomorrow? Will the bus be late? Will this die show a six? Almost nothing in life is certain, and almost nothing is impossible. Most things sit…https://exercises.lol/video-media/igcse_mathematics/probability/probability.enzh.mp4?v=1793313847-24512026-08-15yes https://exercises.lol/videos/igcse_mathematics/statistics2026-10-30https://exercises.lol/video-media/igcse_mathematics/statistics/statistics.thumb.jpg?v=1793325532StatisticsEvery day the world collects numbers about you: how far you travel, how long you sleep, what you score in a test. A long list of numbers tells you almost…https://exercises.lol/video-media/igcse_mathematics/statistics/statistics.enzh.mp4?v=1793325532-24882026-08-15yes https://exercises.lol/videos/igcse_physics/motion-forces-energy2026-10-30https://exercises.lol/video-media/igcse_physics/motion-forces-energy/motion-forces-energy.thumb.jpg?v=1793348630Motion, Forces & EnergyLook around you. A car speeds up. A ball drops. A cup sits still on a table. Physics can describe every one of these — exactly, using numbers. And it all rests…https://exercises.lol/video-media/igcse_physics/motion-forces-energy/motion-forces-energy.enzh.mp4?v=1793348630-214272026-08-15yes https://exercises.lol/videos/igcse_physics/thermal-physics2026-10-31https://exercises.lol/video-media/igcse_physics/thermal-physics/thermal-physics.thumb.jpg?v=1793409792Thermal PhysicsWhat is heat, really? Zoom in far enough, and everything is made of tiny particles, always moving. Heat something, and its particles move faster. Cool it, and…https://exercises.lol/video-media/igcse_physics/thermal-physics/thermal-physics.enzh.mp4?v=1793409792-28642026-08-15yes https://exercises.lol/videos/igcse_physics/waves2026-10-29https://exercises.lol/video-media/igcse_physics/waves/waves.thumb.jpg?v=1793266786WavesDrop a stone in a pond, and rings spread outward. But watch a leaf floating on the surface — it only bobs up and down; it does not travel with the ripples.…https://exercises.lol/video-media/igcse_physics/waves/waves.enzh.mp4?v=1793266786-210302026-08-15yes https://exercises.lol/videos/igcse_physics/electricity-magnetism2026-10-30https://exercises.lol/video-media/igcse_physics/electricity-magnetism/electricity-magnetism.thumb.jpg?v=1793350323Electricity & MagnetismFlick a switch and a light comes on. Hold a magnet near iron and it pulls. These two forces — electricity and magnetism — look separate, but they are deeply…https://exercises.lol/video-media/igcse_physics/electricity-magnetism/electricity-magnetism.enzh.mp4?v=1793350323-219182026-08-15yes https://exercises.lol/videos/igcse_physics/nuclear-physics2026-10-29https://exercises.lol/video-media/igcse_physics/nuclear-physics/nuclear-physics.thumb.jpg?v=1793305389Nuclear PhysicsEverything around you is made of atoms — yet an atom is almost entirely empty space. If the nucleus were the size of a marble, the whole atom would be the size…https://exercises.lol/video-media/igcse_physics/nuclear-physics/nuclear-physics.enzh.mp4?v=1793305389-29462026-08-15yes https://exercises.lol/videos/igcse_physics/space-physics2026-10-29https://exercises.lol/video-media/igcse_physics/space-physics/space-physics.thumb.jpg?v=1793272423Space PhysicsLook up on a clear night, and you might see a few thousand stars. But that is almost nothing. Our Sun is just one star among a hundred billion in our galaxy…https://exercises.lol/video-media/igcse_physics/space-physics/space-physics.enzh.mp4?v=1793272423-210192026-08-15yes https://exercises.lol/videos/oxford_aqa_igcse_mathematics/topic-012026-10-29https://exercises.lol/video-media/oxford_aqa_igcse_mathematics/topic-01/topic-01.thumb.jpg?v=1793282905NumberUnit 3.1 has no formulae sheet: the specification is the recall list. Know the compound interest formula, that a rounded value lies half a unit either side…https://exercises.lol/video-media/oxford_aqa_igcse_mathematics/topic-01/topic-01.enzh.mp4?v=1793282905-23292026-10-29yes https://exercises.lol/videos/oxford_aqa_igcse_mathematics/topic-022026-10-29https://exercises.lol/video-media/oxford_aqa_igcse_mathematics/topic-02/topic-02.thumb.jpg?v=1793282834AlgebraUnit 3.2 is the biggest unit, 35 percent of each Extension paper, and there is no formulae sheet. Recall the quadratic formula and completed square, the line…https://exercises.lol/video-media/oxford_aqa_igcse_mathematics/topic-02/topic-02.enzh.mp4?v=1793282834-22362026-10-29yes https://exercises.lol/videos/oxford_aqa_igcse_mathematics/topic-032026-10-29https://exercises.lol/video-media/oxford_aqa_igcse_mathematics/topic-03/topic-03.thumb.jpg?v=1793282602Geometry and measuresUnit 3.3 has no formulae sheet, so these are the facts to recall. The circle's circumference and area, with a sector as a fraction theta over 360 of each. A…https://exercises.lol/video-media/oxford_aqa_igcse_mathematics/topic-03/topic-03.enzh.mp4?v=1793282602-23192026-10-29yes https://exercises.lol/videos/oxford_aqa_igcse_mathematics/topic-042026-10-29https://exercises.lol/video-media/oxford_aqa_igcse_mathematics/topic-04/topic-04.thumb.jpg?v=1793283082Statistics and probabilityFour facts carry unit 3.4. A histogram with unequal widths plots frequency density, so the area is the frequency. Cumulative frequency plots at the upper…https://exercises.lol/video-media/oxford_aqa_igcse_mathematics/topic-04/topic-04.enzh.mp4?v=1793283082-22092026-10-29yes https://exercises.lol/videos/oxford_aqa_igcse_physics/topic-012026-10-30https://exercises.lol/video-media/oxford_aqa_igcse_physics/topic-01/topic-01.thumb.jpg?v=1793397269Forces and their effectsEvery push, pull and hold in the world is a force. This topic organises them: contact and non-contact interactions, scalars and vectors, Newton's three laws…https://exercises.lol/video-media/oxford_aqa_igcse_physics/topic-01/topic-01.enzh.mp4?v=1793397269-24162026-10-29yes https://exercises.lol/videos/oxford_aqa_igcse_physics/topic-022026-10-30https://exercises.lol/video-media/oxford_aqa_igcse_physics/topic-02/topic-02.thumb.jpg?v=1793396531EnergyNothing destroys energy. It is only moved between stores, and part of it is dissipated into less useful forms. This topic builds the accounting: work and…https://exercises.lol/video-media/oxford_aqa_igcse_physics/topic-02/topic-02.enzh.mp4?v=1793396531-23002026-10-29yes https://exercises.lol/videos/oxford_aqa_igcse_physics/topic-032026-10-30https://exercises.lol/video-media/oxford_aqa_igcse_physics/topic-03/topic-03.thumb.jpg?v=1793396605WavesWaves move energy from a source to a receiver without moving matter: light to an eye, sound to an ear, radio to a phone. This topic builds the wave model…https://exercises.lol/video-media/oxford_aqa_igcse_physics/topic-03/topic-03.enzh.mp4?v=1793396605-23602026-10-29yes https://exercises.lol/videos/oxford_aqa_igcse_physics/topic-042026-10-30https://exercises.lol/video-media/oxford_aqa_igcse_physics/topic-04/topic-04.thumb.jpg?v=1793396560Particle model of matterEverything is made of particles. In a solid they are fixed in place and touching. In a liquid they still touch, but move past each other at random. In a gas…https://exercises.lol/video-media/oxford_aqa_igcse_physics/topic-04/topic-04.enzh.mp4?v=1793396560-22502026-10-29yes https://exercises.lol/videos/oxford_aqa_igcse_physics/topic-052026-10-30https://exercises.lol/video-media/oxford_aqa_igcse_physics/topic-05/topic-05.thumb.jpg?v=1793402172Electricity and magnetismElectricity is charge on the move. Potential difference drives the charge, every component resists it, and every current makes a magnetic field. This topic…https://exercises.lol/video-media/oxford_aqa_igcse_physics/topic-05/topic-05.enzh.mp4?v=1793402172-22892026-10-29yes https://exercises.lol/videos/oxford_aqa_igcse_physics/topic-062026-10-30https://exercises.lol/video-media/oxford_aqa_igcse_physics/topic-06/topic-06.thumb.jpg?v=1793402181Generating and distributing electricityMove a magnet near a coil and a potential difference appears. This topic follows electricity from the generator, through the transformers of the national grid…https://exercises.lol/video-media/oxford_aqa_igcse_physics/topic-06/topic-06.enzh.mp4?v=1793402181-22962026-10-29yes https://exercises.lol/videos/oxford_aqa_igcse_physics/topic-072026-10-29https://exercises.lol/video-media/oxford_aqa_igcse_physics/topic-07/topic-07.thumb.jpg?v=1793284245Nuclear physicsAn atom is about 10 to the minus 10 metres across, with a tiny nucleus at its centre and electrons around it. The nucleus is about a hundred-thousandth of the…https://exercises.lol/video-media/oxford_aqa_igcse_physics/topic-07/topic-07.enzh.mp4?v=1793284245-22452026-10-29yes https://exercises.lol/videos/oxford_aqa_igcse_physics/topic-082026-10-29https://exercises.lol/video-media/oxford_aqa_igcse_physics/topic-08/topic-08.thumb.jpg?v=1793284464Space physicsGravity gathers dust into stars. Stars fuse the elements. And the red-shift of distant galaxies tells us the whole universe is expanding from a beginning about…https://exercises.lol/video-media/oxford_aqa_igcse_physics/topic-08/topic-08.enzh.mp4?v=1793284464-22112026-10-29yes https://exercises.lol/videos/sat/session4-012026-11-08https://exercises.lol/video-media/sat/session4-01/session4-01.thumb.jpg?v=1794123489Information and IdeasIn 1847 Ignaz Semmelweis, a doctor at Vienna General Hospital, compared two maternity clinics. In the clinic run by doctors, who often came straight from…https://exercises.lol/video-media/sat/session4-01/session4-01.enzh.mp4?v=1794123489-22852026-10-29yes https://exercises.lol/videos/sat/session4-022026-11-08https://exercises.lol/video-media/sat/session4-02/session4-02.thumb.jpg?v=1794123440Craft and StructureIn 1879 James Murray, a Scottish schoolteacher, took charge of a new dictionary that would record every English word with dated quotations showing how its…https://exercises.lol/video-media/sat/session4-02/session4-02.enzh.mp4?v=1794123440-22682026-10-29yes https://exercises.lol/videos/sat/session4-032026-11-08https://exercises.lol/video-media/sat/session4-03/session4-03.thumb.jpg?v=1794126291Expression of IdeasIn 1918 William Strunk Jr., an English professor at Cornell University, printed a small book for his students. Rule 17 said: "Omit needless words." One of…https://exercises.lol/video-media/sat/session4-03/session4-03.enzh.mp4?v=1794126291-22712026-10-29yes https://exercises.lol/videos/sat/session4-042026-11-08https://exercises.lol/video-media/sat/session4-04/session4-04.thumb.jpg?v=1794125924Standard English ConventionsIn 2003 Lynne Truss, a British journalist, published a book about punctuation with a joke for its title. A panda walks into a café, eats a sandwich, fires a…https://exercises.lol/video-media/sat/session4-04/session4-04.enzh.mp4?v=1794125924-22812026-10-29yes https://exercises.lol/videos/sat/session4-052026-11-08https://exercises.lol/video-media/sat/session4-05/session4-05.thumb.jpg?v=1794126159AlgebraAround 820 the scholar Muhammad ibn Musa al-Khwarizmi, working in Baghdad's House of Wisdom, wrote a book on solving equations by two moves: al-jabr…https://exercises.lol/video-media/sat/session4-05/session4-05.enzh.mp4?v=1794126159-22932026-10-29yes https://exercises.lol/videos/sat/session4-062026-11-08https://exercises.lol/video-media/sat/session4-06/session4-06.thumb.jpg?v=1794126243Advanced MathIn 1638 Galileo Galilei published Two New Sciences, written while he was under house arrest. In it he showed, by rolling balls down a gentle slope and timing…https://exercises.lol/video-media/sat/session4-06/session4-06.enzh.mp4?v=1794126243-23582026-10-29yes https://exercises.lol/videos/sat/session4-072026-11-08https://exercises.lol/video-media/sat/session4-07/session4-07.thumb.jpg?v=1794124014Problem-Solving and Data AnalysisIn 1936 the magazine Literary Digest mailed questionnaires to about ten million Americans, chosen from telephone directories and car registrations, and…https://exercises.lol/video-media/sat/session4-07/session4-07.enzh.mp4?v=1794124014-22942026-10-29yes https://exercises.lol/videos/sat/session4-082026-11-08https://exercises.lol/video-media/sat/session4-08/session4-08.thumb.jpg?v=1794124596Geometry and TrigonometryAncient writers tell a story about Thales of Miletus, around 600 BC. Visiting Egypt, he measured the height of a pyramid without climbing it. He waited for the…https://exercises.lol/video-media/sat/session4-08/session4-08.enzh.mp4?v=1794124596-23092026-10-29yes https://exercises.lol/videos/sat/session4-092026-11-08https://exercises.lol/video-media/sat/session4-09/session4-09.thumb.jpg?v=1794126647Linear parameters, solution counts and inequalitiesIn 1557 the Welsh mathematician Robert Recorde published The Whetstone of Witte and introduced the equals sign. He chose two parallel lines, he wrote, "bicause…https://exercises.lol/video-media/sat/session4-09/session4-09.enzh.mp4?v=1794126647-23652026-10-29yes https://exercises.lol/videos/sat/session4-102026-11-08https://exercises.lol/video-media/sat/session4-10/session4-10.thumb.jpg?v=1794126449Equivalent expressions and domain restrictionsAround 820 the scholar Muhammad ibn Musa al-Khwarizmi, working in Baghdad's House of Wisdom, wrote a book on solving equations. Its title named two moves…https://exercises.lol/video-media/sat/session4-10/session4-10.enzh.mp4?v=1794126449-23192026-10-29yes https://exercises.lol/videos/sat/session4-112026-10-29https://exercises.lol/video-media/sat/session4-11/session4-11.thumb.jpg?v=1793315355Nonlinear equations and mixed systemsA candidate root must satisfy the original equation. In the square root of x plus 6 equals x, the right side must be nonnegative. Squaring gives x squared…https://exercises.lol/video-media/sat/session4-11/session4-11.enzh.mp4?v=1793315355-22152026-10-29yes https://exercises.lol/videos/sat/session4-122026-10-29https://exercises.lol/video-media/sat/session4-12/session4-12.thumb.jpg?v=1793286538Nonlinear functions, transformations and growthVertex form a times x minus h squared plus k reveals the turning point h comma k. For H of t equals negative 2 times t minus 4 squared plus 32, the maximum is…https://exercises.lol/video-media/sat/session4-12/session4-12.enzh.mp4?v=1793286538-22292026-10-29yes https://exercises.lol/videos/sat/session4-132026-10-29https://exercises.lol/video-media/sat/session4-13/session4-13.thumb.jpg?v=1793281308Ratios, unit conversion and successive percentagesA rate compares quantities with their units. v equals d divided by t, which is ninety kilometres divided by one point five hours, equaling sixty kilometres per…https://exercises.lol/video-media/sat/session4-13/session4-13.enzh.mp4?v=1793281308-22252026-10-29yes https://exercises.lol/videos/sat/session4-142026-11-08https://exercises.lol/video-media/sat/session4-14/session4-14.thumb.jpg?v=1794126973Distributions, transformations and spreadIn 1906, at a livestock fair in Plymouth, England, about 800 visitors paid to guess the weight of an ox after butchering. The scientist Francis Galton later…https://exercises.lol/video-media/sat/session4-14/session4-14.enzh.mp4?v=1794126973-23002026-10-29yes https://exercises.lol/videos/sat/session4-152026-10-29https://exercises.lol/video-media/sat/session4-15/session4-15.thumb.jpg?v=1793315359Scatterplots, model residuals and predictionsA residual is observed minus predicted output. A journey model T equals 5 plus 2 d uses minutes for T and kilometres for d. T of 4 equals 5 min plus 2 min per…https://exercises.lol/video-media/sat/session4-15/session4-15.enzh.mp4?v=1793315359-22232026-10-29yes https://exercises.lol/videos/sat/session4-162026-10-29https://exercises.lol/video-media/sat/session4-16/session4-16.thumb.jpg?v=1793286579Probability from a table and a restricted groupConditional probability restricts the denominator. Of 40 club members, 12 cycle; 8 of those cyclists wear a helmet. P of H given C equals n of H intersection C…https://exercises.lol/video-media/sat/session4-16/session4-16.enzh.mp4?v=1793286579-22152026-10-29yes https://exercises.lol/videos/sat/session4-172026-11-08https://exercises.lol/video-media/sat/session4-17/session4-17.thumb.jpg?v=1794126924Sampling, margin of error and causal claimsIn 1936 the magazine Literary Digest mailed about 10 million ballots asking Americans how they would vote for president. About 2.4 million came back, and the…https://exercises.lol/video-media/sat/session4-17/session4-17.enzh.mp4?v=1794126924-23002026-10-29yes https://exercises.lol/videos/sat/session4-182026-10-29https://exercises.lol/video-media/sat/session4-18/session4-18.thumb.jpg?v=1793317194Scale factors, angle relationships and trianglesA scale factor k changes every corresponding length. A sub 2 equals k squared times A sub 1, and V sub 2 equals k cubed times V sub 1 for similar shapes. If k…https://exercises.lol/video-media/sat/session4-18/session4-18.enzh.mp4?v=1793317194-22772026-10-29yes https://exercises.lol/videos/sat/session4-192026-11-08https://exercises.lol/video-media/sat/session4-19/session4-19.thumb.jpg?v=1794125391Circle equations, arcs and unit-circle trigonometryIn 1637 René Descartes published La Géométrie as an appendix to his Discourse on Method. It showed how to describe a curve by an equation in two coordinates…https://exercises.lol/video-media/sat/session4-19/session4-19.enzh.mp4?v=1794125391-23112026-10-29yes https://exercises.lol/videos/sat/session4-202026-11-08https://exercises.lol/video-media/sat/session4-20/session4-20.thumb.jpg?v=1794125967Central ideas, details and the scope of a claimIn late August 1854 cholera killed more than 500 people in ten days in Soho, London. The doctor John Snow marked each death on a street map and saw them…https://exercises.lol/video-media/sat/session4-20/session4-20.enzh.mp4?v=1794125967-23152026-10-29yes https://exercises.lol/videos/sat/session4-212026-11-08https://exercises.lol/video-media/sat/session4-21/session4-21.thumb.jpg?v=1794127336Choose evidence for a precise textual or numerical claimDuring the Crimean War, in 1854–1855, the nurse Florence Nightingale kept records at the British army hospital at Scutari. Her figures showed that far more…https://exercises.lol/video-media/sat/session4-21/session4-21.enzh.mp4?v=1794127336-23332026-10-29yes https://exercises.lol/videos/sat/session4-222026-11-08https://exercises.lol/video-media/sat/session4-22/session4-22.thumb.jpg?v=1794126570Complete a passage with a warranted inferenceIn 1747 James Lind, a surgeon on HMS Salisbury, took twelve sailors with scurvy and divided them into six pairs. Each pair received a different treatment…https://exercises.lol/video-media/sat/session4-22/session4-22.enzh.mp4?v=1794126570-23102026-10-29yes https://exercises.lol/videos/sat/session4-232026-11-08https://exercises.lol/video-media/sat/session4-23/session4-23.thumb.jpg?v=1794125387Words in context: meaning, polarity and collocationIn April 1755 Samuel Johnson published his Dictionary of the English Language, the result of about nine years' work with a small team of assistants. It defined…https://exercises.lol/video-media/sat/session4-23/session4-23.enzh.mp4?v=1794125387-23042026-10-29yes https://exercises.lol/videos/sat/session4-242026-11-08https://exercises.lol/video-media/sat/session4-24/session4-24.thumb.jpg?v=1794126170Text structure, sentence function and rhetorical purposeIn 1931 Harry Beck, an engineering draughtsman who had been laid off by the London Underground, drew a new map of the network in his spare time. The old maps…https://exercises.lol/video-media/sat/session4-24/session4-24.enzh.mp4?v=1794126170-23102026-10-29yes https://exercises.lol/videos/sat/session4-252026-11-08https://exercises.lol/video-media/sat/session4-25/session4-25.thumb.jpg?v=1794126809Compare two texts without merging their claimsIn the early 1860s the French scientists Louis Pasteur and Félix Pouchet argued about where the microbes in spoiled broth came from. Both men saw the same…https://exercises.lol/video-media/sat/session4-25/session4-25.enzh.mp4?v=1794126809-23222026-10-29yes https://exercises.lol/videos/sat/session4-262026-11-08https://exercises.lol/video-media/sat/session4-26/session4-26.thumb.jpg?v=1794127404Use research notes for the requested rhetorical goalIn 1962 the biologist Rachel Carson published Silent Spring, about the effects of pesticides such as DDT on birds, fish and people. Carson had spent years…https://exercises.lol/video-media/sat/session4-26/session4-26.enzh.mp4?v=1794127404-22902026-10-24yes https://exercises.lol/videos/sat/session4-272026-11-08https://exercises.lol/video-media/sat/session4-27/session4-27.thumb.jpg?v=1794127122Transitions: choose the logical relationship firstOn 19 November 1863 Abraham Lincoln spoke for about two minutes at the dedication of a soldiers' cemetery at Gettysburg, Pennsylvania. His speech had about 270…https://exercises.lol/video-media/sat/session4-27/session4-27.enzh.mp4?v=1794127122-23142026-10-29yes https://exercises.lol/videos/sat/session4-282026-11-08https://exercises.lol/video-media/sat/session4-28/session4-28.thumb.jpg?v=1794127246Sentence boundaries, colons and nonessential informationIn 2017 a US federal appeals court in Boston decided a case about a missing comma. A Maine law listed tasks for which workers did not get overtime pay: "the…https://exercises.lol/video-media/sat/session4-28/session4-28.enzh.mp4?v=1794127246-23412026-10-29yes https://exercises.lol/videos/sat/session4-292026-10-29https://exercises.lol/video-media/sat/session4-29/session4-29.thumb.jpg?v=1793288467Agreement, verb forms, modifiers and logical parallelismAgreement follows the subject head, not the nearest noun. “The set of keys is missing” has singular set. An introductory modifier must describe the correct…https://exercises.lol/video-media/sat/session4-29/session4-29.enzh.mp4?v=1793288467-22502026-10-29yes https://exercises.lol/videos/toefl/overview-scores-and-preparation2026-10-28https://exercises.lol/video-media/toefl/overview-scores-and-preparation/overview-scores-and-preparation.thumb.jpg?v=1793204749TOEFL Overview: Scores, Tasks and PreparationImagine a learner who reads academic pages confidently but misses a room change in a short announcement. Another learner understands the announcement but…https://exercises.lol/video-media/toefl/overview-scores-and-preparation/overview-scores-and-preparation.enzh.mp4?v=1793204749-212572026-10-03yes https://exercises.lol/videos/toefl/reading-worked-practice2026-10-30https://exercises.lol/video-media/toefl/reading-worked-practice/reading-worked-practice.thumb.jpg?v=1793398181Reading: Worked Classroom PracticeThe Reading section gives you about thirty minutes and about fifty items. That is much faster than the old test, and the items are shorter, so the skill being…https://exercises.lol/video-media/toefl/reading-worked-practice/reading-worked-practice.enzh.mp4?v=1793398181-211142026-10-08yes https://exercises.lol/videos/toefl/listening-worked-practice2026-10-30https://exercises.lol/video-media/toefl/listening-worked-practice/listening-worked-practice.thumb.jpg?v=1793396527Listening: Worked Classroom PracticeThe Listening section gives you about twenty-nine minutes and about forty-seven items, in four kinds of task: listen and choose a response, listen to a…https://exercises.lol/video-media/toefl/listening-worked-practice/listening-worked-practice.enzh.mp4?v=1793396527-210232026-10-08yes https://exercises.lol/videos/toefl/writing-original-practice2026-10-30https://exercises.lol/video-media/toefl/writing-original-practice/writing-original-practice.thumb.jpg?v=1793319354Writing: Original Classroom PracticeThis supplement gives original classroom practice for all three Writing tasks: building sentences, writing an email, and joining an academic discussion.…https://exercises.lol/video-media/toefl/writing-original-practice/writing-original-practice.enzh.mp4?v=1793319354-28052026-10-03yes https://exercises.lol/videos/toefl/speaking-worked-practice2026-10-30https://exercises.lol/video-media/toefl/speaking-worked-practice/speaking-worked-practice.thumb.jpg?v=1793402282Speaking: Worked Classroom PracticeThe Speaking section gives you about eight minutes and about eleven items, in two kinds of task: listen and repeat, and take an interview. You speak into a…https://exercises.lol/video-media/toefl/speaking-worked-practice/speaking-worked-practice.enzh.mp4?v=1793402282-28062026-10-08yes