経済学入門
国際バカロレア · IB Diploma · Economics · HL トピック 1 6:19 英語ナレーション・英語＋中文字幕 burning-in
章
Transcript
A government has 10 billion to spend.
一个政府有一百亿可以支出。
It can build one hospital, with benefits valued at 10 billion, or two schools, with benefits valued at 7 billion.
它可以建一所医院，收益估值一百亿；或者建两所学校，收益估值七十亿。
It cannot have both.
两者不能兼得。
Whatever it chooses, it gives up the other.
无论选哪个，都要放弃另一个。
That is the whole of economics in one decision: scarce resources, a choice, and a cost.
这就是一个决定中的全部经济学：稀缺的资源、一个选择和一个代价。
Unit 1 has two parts.
第一单元有两部分。
Section 1.1 asks what economics is: scarcity, choice, the economic agents, and positive and normative statements.
1.1 问经济学是什么：稀缺、选择、经济主体，以及实证表述和规范表述。
Section 1.2 asks how economists approach the world: the scientific method, models, the ceteris paribus assumption, and the nine key concepts that frame the whole course.
1.2 问经济学家如何看待世界：科学方法、模型、其他条件不变假设，以及贯穿整个课程的九个核心概念。
Economics studies the choices made by consumers, producers and the government under scarcity: unlimited wants against finite resources.
经济学研究消费者、生产者和政府在稀缺条件下做出的选择：无限的欲望对有限的资源。
Because resources are scarce, every choice has an opportunity cost, the next-best alternative given up.
因为资源稀缺，每个选择都有机会成本，即放弃的次优选择。
An hour spent revising cannot also be spent at work.
用来复习的一小时就不能同时用来工作。
So every economy must answer three questions: what to produce, how to produce it, and for whom.
所以每个经济体都必须回答三个问题：生产什么、如何生产、为谁生产。
Economic resources, the factors of production, are land, labour, capital and enterprise.
经济资源，即生产要素，包括土地、劳动、资本和企业家才能。
Each earns a reward: land earns rent, labour earns wages, capital earns interest, and enterprise earns profit.
每种要素都获得回报：土地得到租金，劳动得到工资，资本得到利息，企业家才能得到利润。
A distinction runs through every data response.
每道数据题都贯穿着一个区分。
A positive statement can be tested against evidence: the inflation rate fell to 3 percent.
实证表述可以用证据检验：通货膨胀率降到了百分之三。
A normative statement carries a value judgement: inflation should be lower.
规范表述带有价值判断：通货膨胀应该更低。
Economists can disagree about values while agreeing about facts, so keep the two apart in every answer.
经济学家可能在事实上一致，却在价值上分歧，所以每个答案都要把两者分开。
Back to the government.
回到那个政府。
Choosing the hospital has an opportunity cost: the two schools, worth 7 billion of benefit.
选择医院的机会成本是两所学校，价值七十亿的收益。
The choice is rational if the hospital's benefit, 10 billion, is more than the benefit of the best alternative given up.
如果医院的收益一百亿大于所放弃的最佳选择的收益，这个选择就是理性的。
Economics follows the scientific method.
经济学遵循科学方法。
Observe, form a hypothesis, and build a model: a simplified picture of reality, such as a demand curve or a production possibility curve.
观察，提出假设，建立模型：对现实的简化描述，例如需求曲线或生产可能性曲线。
Make predictions and test them against data, and revise the model when it fails.
做出预测，用数据检验，模型失败时加以修正。
Models simplify on purpose: their value is explanation and prediction, not realism.
模型是有意简化的，它的价值在于解释和预测，而不是逼真。
The ceteris paribus assumption means all other things equal. It lets the economist isolate one relationship at a time: how quantity demanded responds to price, holding income and tastes fixed.
“其他条件不变”假设让经济学家一次只分析一种关系：在收入和偏好不变的情况下，需求量如何随价格变化。
The same discipline is used in every later unit.
之后每个单元都使用同样的方法。
The whole course is framed by nine key concepts.
整个课程由九个核心概念贯穿。
Scarcity and choice are the underlying problem.
稀缺和选择是基本问题。
Efficiency and equity ask how well and how fairly resources are used.
效率和公平问资源使用得有多好、多公平。
Economic well-being and sustainability are outcomes now and for the future.
经济福祉和可持续性关乎现在和未来的结果。
Change, interdependence and intervention complete the set: how the world shifts, how agents and nations are linked, and when governments act.
变化、相互依存和干预构成其余部分：世界如何变化，主体和国家如何相互联系，以及政府何时采取行动。
A tuition subsidy is a model question.
学费补贴是一个模型问题。
The hypothesis: lower fees raise enrolment.
假设：降低学费会提高入学人数。
The demand model predicts that enrolment rises when price falls, ceteris paribus.
需求模型预测，在其他条件不变时，价格下降，入学人数上升。
The test compares enrolment before and after.
检验比较补贴前后的入学人数。
If enrolment stays flat because incomes also fell, other things were not equal, and the economist goes back to re-specify the model.
如果因为收入也下降了而入学人数持平，说明其他条件并未不变，经济学家就要回去重新设定模型。
An economy can produce these combinations of food and machines with all its resources and today's technology.
一个经济体用全部资源和现有技术，可以生产以下食品和机器的组合。
At A it makes 100 thousand machines and no food.
在 A 点，它生产十万台机器，没有食品。
Moving through B, C and D to E, it makes 40 million tonnes of food but only 40 thousand machines.
经过 B、C、D 到达 E 点，它生产四千万吨食品，但只有四万台机器。
Joining the points gives the production possibility curve.
把这些点连起来，就是生产可能性曲线。
Each extra 10 million tonnes of food costs more machines: 5, then 10, then 20, then 25.
每多生产一千万吨食品，要放弃的机器越来越多：5，然后 10、20、25。
That is increasing opportunity cost, and it makes the curve bow outwards.
这就是机会成本递增，它使曲线向外凸。
Resources are not equally good at both jobs: the first workers and land moved to farming are the best farmers and the best soil; later ones are better suited to factories.
资源并不同样适合两种工作：最先转去务农的是最好的农民和最好的土地；后转去的更适合在工厂工作。
Producing 20 food and 60 machines is possible but inefficient: at point C the economy could have 85 machines with the same food.
生产 20 单位食品和 60 单位机器是可能的，但没有效率：在 C 点，同样的食品可以配 85 单位机器。
Producing 30 food and 80 machines is unattainable now, because D gives only 65 machines.
生产 30 单位食品和 80 单位机器目前做不到，因为 D 点只有 65 单位机器。
Better farming technology would pivot the curve outwards along the food axis.
更好的农业技术会让曲线沿食品轴向外转动。
World military spending reached a record of about 2.7 trillion US dollars in 2024.
2024 年，全球军费开支达到创纪录的约 2.7 万亿美元。
For each government, the opportunity cost is the schools, hospitals or lower taxes it could have funded instead.
对每个政府来说，机会成本是本可以用这笔钱建设的学校、医院或减免的税收。
Economists can measure the size of the trade-off, a positive question. Whether the spending is worth it is a normative judgement.
经济学家可以衡量这种取舍的大小，这是实证问题；这笔开支是否值得，则是规范判断。
Paper 1 is an extended-response paper.
试卷一是论述题。
Part (a) asks you to explain with a diagram; part (b) asks you to evaluate with real-world examples.
(a) 部分要求用图解释；(b) 部分要求用现实例子评价。
Define the key terms.
界定关键术语。
Draw a fully labelled diagram and refer to it.
画出完整标注的图并在文中引用。
Explain the chain of cause and effect step by step.
逐步解释因果链。
Use a real-world example with a country, a year and a number.
使用现实例子，写明国家、年份和数字。
Evaluate: short run against long run, different stakeholders, the assumptions.
评价：短期对长期、不同利益相关者、各种假设。
And conclude with a judgement that answers the question as set.
最后给出回答题目的判断。
Check yourself.
自我检查。
Can you define economics through scarcity and choice, and name the agents?
你能用稀缺和选择定义经济学，并说出经济主体吗？
Apply opportunity cost to consumers, producers and government?
能把机会成本用于消费者、生产者和政府吗？
Name the factors of production and their rewards?
能说出生产要素及其回报吗？
Tell a positive from a normative statement?
能区分实证表述和规范表述吗？
Describe the scientific method loop and ceteris paribus?
能描述科学方法的循环和其他条件不变假设吗？
Read opportunity cost off a production possibility curve?
能从生产可能性曲线上读出机会成本吗？
And use the nine key concepts in a Paper 1 answer: name the concept, then the theory?
能在试卷一答案中运用九个核心概念：先说出概念，再说理论吗？