Topic 2: Organisation
AQA · GCSE · Biology נושא 2 47:16 קריאת קול באנגלית · תרגום אנגלי + סינית שרוף בתוך הסרטון
פרקים
תרגום טקסט
Organisation is the bridge from cells to bodies. Cells with the same job form a tissue; tissues together form an organ; organs cooperate in organ systems.
组织是从细胞到身体的桥梁：同类细胞构成组织，组织构成器官，器官协作成系统。
The digestive system is the named example, and this topic adds the blood, the heart and the plant transport system — with enzymes doing the chemistry at every step.
消化系统是指定例子；本专题再加上血液、心脏和植物运输系统——每一步化学反应都由酶驱动。
Follow one example up the levels.
沿着一个例子逐级向上看。
A muscle cell is one basic living unit.
肌肉细胞是一个基本的生命单位。
Muscle cells together form muscular tissue, similar cells sharing a job.
许多肌肉细胞组成肌肉组织，即相似的细胞共同完成一项工作。
The stomach is an organ, because different tissues work together: muscular, glandular and epithelial tissue.
胃是一个器官，因为不同的组织协同工作：肌肉组织、腺体组织和上皮组织。
Several organs form the digestive system, which digests and absorbs food.
几个器官组成消化系统，负责消化和吸收食物。
And the systems together make up the organism.
各个系统共同构成生物体。
Define a tissue and give an example from the digestive system.
给组织下定义，并举一个消化系统中的例子。
Then explain why the whole stomach counts as an organ.
然后解释为什么整个胃算作一个器官。
Give the definition before the example, and separate similar cells from different tissues.
先写定义再举例，并区分相似的细胞和不同的组织。
Pause and try it.
暂停并试着回答。
A tissue is a group of cells with a similar structure and function: muscular tissue contracts.
组织是一群结构和功能相似的细胞：肌肉组织能够收缩。
The stomach is an organ: muscular tissue mixes the food, glandular tissue releases digestive juice, and epithelial tissue covers its surfaces.
胃是一个器官：肌肉组织搅拌食物，腺体组织分泌消化液，上皮组织覆盖表面。
The stomach and intestines work together as a system to digest food and absorb the soluble products.
胃和肠作为一个系统协同工作，消化食物并吸收可溶性产物。
An organ has several types of tissue, not just many cells.
器官由几种组织构成，而不只是很多细胞。
These are simple shape models, not real molecules.
这些是简单的形状模型，不是真实的分子。
The substrate fits the enzyme's active site because their shapes match.
底物能与酶的活性部位结合，是因为二者形状吻合。
If the active site changes shape, the substrate may no longer fit.
如果活性部位的形状改变，底物可能就无法结合了。
Bind: the substrate fits the complementary active site, the simple lock-and-key model.
结合：底物与互补的活性部位相契合，这就是简化的锁钥模型。
React: the enzyme catalyses that one reaction without being used up.
反应：酶催化这一特定反应，自身不被消耗。
Release: the products leave, and the enzyme can bind another substrate.
释放：产物离开，酶可以再结合另一个底物。
Enzymes are proteins, not living things, so never say they are killed.
酶是蛋白质，不是生物，所以不要说酶被“杀死”。
Amylase, a carbohydrase, breaks down starch into simple sugars.
淀粉酶属于糖酶，把淀粉分解成单糖。
Protease breaks down protein into amino acids.
蛋白酶把蛋白质分解成氨基酸。
Lipase breaks down lipids into glycerol and fatty acids.
脂肪酶把脂类分解成甘油和脂肪酸。
Do not give glucose as the direct product of starch breakdown by amylase.
不要把葡萄糖说成淀粉酶分解淀粉的直接产物。
Where are they made?
它们在哪里产生？
Amylase is made in the salivary glands, the pancreas and the small intestine.
淀粉酶由唾液腺、胰腺和小肠产生。
Protease is made in the stomach, the pancreas and the small intestine.
蛋白酶由胃、胰腺和小肠产生。
Lipase is made in the pancreas and the small intestine.
脂肪酶由胰腺和小肠产生。
The place an enzyme is made is not always the only place it acts.
酶产生的地方，不一定是它唯一起作用的地方。
Without looking back at the table: name the enzyme that digests starch, two places where it is made, and its product.
不要回看表格：说出消化淀粉的酶、它产生的两个部位，以及它的产物。
Pause and try it.
暂停并试着回答。
Amylase digests starch.
淀粉酶消化淀粉。
The salivary glands and the pancreas are two valid places where it is made; the small intestine is also accepted.
唾液腺和胰腺是它产生的两个正确部位，小肠也可以。
The product is simple sugars, such as maltose, not glucose.
产物是单糖，例如麦芽糖，而不是葡萄糖。
Digestion makes small, soluble products, and absorption then moves them through the wall of the intestine into the blood.
消化产生小的可溶性产物，吸收再把它们通过肠壁送入血液。
When it is cold, particles move slowly and there are fewer successful collisions; warming up can restore a faster rate.
温度低时，粒子运动慢，有效碰撞少；升温后速率可以恢复加快。
Near the optimum, the active site has a suitable shape and collisions are frequent, so the rate is high.
在最适温度附近，活性部位形状合适，碰撞频繁，所以速率高。
When it is too hot, the active site changes shape permanently, and cooling does not restore it.
温度过高时，活性部位的形状发生永久改变，冷却也不能恢复。
An extreme pH can change the active site too.
极端的pH也会改变活性部位。
Explain why amylase that has been very hot stays inactive after cooling, while cold amylase can work faster once it is warmed.
解释为什么经过高温的淀粉酶冷却后仍然没有活性，而低温下的淀粉酶升温后可以加快反应。
Explain the active site at the high temperature, and the collisions at the low one.
分别解释高温下的活性部位，以及低温下的粒子碰撞。
Pause and try it.
暂停并试着回答。
At eighty degrees, amylase is denatured: its active site changes shape permanently.
在八十摄氏度时，淀粉酶变性：活性部位的形状永久改变。
Starch no longer fits, and cooling does not rebuild the original active site.
淀粉无法再结合，冷却也不能重建原来的活性部位。
At five degrees, the particles have little kinetic energy, so there are fewer successful collisions.
在五摄氏度时，粒子动能小，有效碰撞少。
The enzyme is undamaged, and works faster when it is warmed.
酶并没有受损，升温后反应会加快。
Give two functions of bile, and explain why each one increases the activity of lipase.
说出胆汁的两个作用，并解释每个作用为什么能提高脂肪酶的活性。
Say where bile is made and stored, and remember that bile is not an enzyme.
说出胆汁在哪里产生和储存，并记住胆汁不是酶。
Pause and try it.
暂停并试着回答。
Bile is made in the liver and stored in the gall bladder.
胆汁由肝脏产生，储存在胆囊中。
It is alkaline, so it neutralises stomach acid, giving suitable conditions for lipase in the small intestine.
胆汁呈碱性，能中和胃酸，为小肠中的脂肪酶提供适宜的条件。
It also emulsifies fat into smaller droplets, with a larger total surface area, so lipase works faster.
它还把脂肪乳化成更小的油滴，总表面积更大，所以脂肪酶作用更快。
Emulsifying changes the droplet size; lipase does the chemical breakdown.
乳化只改变油滴大小，化学分解由脂肪酶完成。
Four food tests.
四种食物检测。
For reducing sugar, add Benedict's solution and heat it in a hot water bath: a positive result is green, yellow, orange or brick-red.
检测还原糖：加入本尼迪特试剂，在热水浴中加热，阳性结果为绿色、黄色、橙色或砖红色。
Iodine turns blue-black with starch.
淀粉遇碘液变蓝黑色。
Biuret turns purple or lilac with protein.
蛋白质遇双缩脲试剂变紫色或淡紫色。
For lipid, mix with Sudan III and let it settle: a red-stained oily layer is positive.
检测脂类：加入苏丹三染液混匀后静置，出现红色油层为阳性。
Test separate portions of the sample.
每项检测用样品的不同部分。
Benedict's stays blue, iodine turns blue-black, and Biuret stays blue.
本尼迪特试剂保持蓝色，碘液变成蓝黑色，双缩脲试剂保持蓝色。
What has been detected, and why is the Benedict's test heated?
检测出了什么？ 为什么本尼迪特试验要加热？
No lipid test was done, so draw no conclusion about lipid.
没有做脂类检测，所以不要对脂类下结论。
Pause and try it.
暂停并试着回答。
The blue-black iodine shows starch.
碘液变蓝黑色，说明含有淀粉。
No reducing sugar or protein was detected by these tests, but a negative result does not prove they are completely absent.
这些检测没有检出还原糖和蛋白质，但阴性结果并不能证明它们完全不存在。
The hot water bath supplies energy for the Benedict's reaction, and a positive colour need not be brick-red.
热水浴为本尼迪特反应提供能量，阳性颜色不一定是砖红色。
Benedict's does not test for every kind of sugar.
本尼迪特试剂并不能检测所有种类的糖。
These are real exam results.
这是真题的实验结果。
Amylase and starch were kept at four temperatures, then tested with iodine after five minutes.
淀粉酶和淀粉在四个温度下保温，五分钟后用碘液检测。
The iodine started yellow-brown.
碘液原来是黄褐色。
At ten, sixty and ninety degrees it turned blue-black.
在十度、六十度和九十度时，碘液变成蓝黑色。
Only at thirty degrees did it stay yellow-brown.
只有在三十度时，碘液仍是黄褐色。
Explain the results at thirty degrees and at ninety degrees.
解释三十度和九十度时的结果。
At each temperature, say what the colour means, then explain what the enzyme did.
对每个温度，先说出颜色的含义，再解释酶的作用。
Do not call the enzyme dead.
不要说酶“死了”。
Pause and try it.
暂停并试着回答。
At thirty degrees, the yellow-brown iodine means no starch remains, because amylase has broken it down.
在三十度时，碘液为黄褐色，说明没有淀粉剩余，因为淀粉酶已把淀粉分解。
At ninety degrees, the blue-black iodine means starch remains, because amylase has been denatured and could not break the starch down.
在九十度时，碘液为蓝黑色，说明仍有淀粉，因为淀粉酶已经变性，无法分解淀粉。
Evidence and mechanism earn separate marks.
证据和机制分别得分。
Which temperature range should be tested in more detail, to find the best temperature more precisely?
要更精确地找出最适温度，应该在哪个温度范围内做更细致的测试？
Choose one range.
选出一个范围。
One result at thirty degrees cannot pin down an exact optimum.
仅凭三十度的一个结果，不能确定准确的最适温度。
The evidence: only thirty degrees cleared the starch within five minutes, and ten and sixty degrees did not.
证据：只有三十度在五分钟内把淀粉分解完，十度和六十度都没有。
So test more temperatures between ten and sixty degrees.
所以要在十度到六十度之间测试更多温度。
The true peak could be on either side of thirty, so use smaller steps, and repeat.
真正的峰值可能在三十度的任一侧，所以要用更小的间隔并重复实验。
More temperatures give more detail; repeats deal with random variation.
更多温度点提供更多细节，重复实验应对随机波动。
Required practical five: plan an investigation of how pH affects the rate of amylase.
必做实验五：设计实验，探究pH对淀粉酶反应速率的影响。
Include the end point, two control variables, and how you compare rates.
要写出终点、两个控制变量，以及如何比较速率。
How will you change the pH?
如何改变pH？
How will you test for starch every thirty seconds?
如何每三十秒检测一次淀粉？
What makes the comparison fair?
怎样使比较公平？
Pause and plan it.
暂停并构思。
Put separate drops of iodine in a spotting tile, and prepare buffer solutions covering several pH values.
在点滴板上分别滴好碘液，并准备几种不同pH的缓冲液。
Use equal concentrations and volumes of starch and amylase, the same volume of buffer, and the same total volume.
淀粉和淀粉酶的浓度和体积相同，缓冲液体积相同，总体积也相同。
Let the reactants reach the temperature of the same water bath, and keep that temperature constant.
让反应物在同一个水浴中达到相同温度，并保持温度恒定。
The buffers change the pH; the controls isolate its effect.
缓冲液改变pH，控制变量则使pH的影响得以单独显现。
Mix the starch, amylase and buffer, and start the timer straight away.
把淀粉、淀粉酶和缓冲液混合，立即开始计时。
Every thirty seconds, put a fresh small sample onto a new drop of iodine, without carrying iodine back into the tube.
每隔三十秒取少量新样品滴到一滴新的碘液上，不要把碘液带回试管。
Record the first time the iodine stays yellow-brown: starch is no longer detected.
记录碘液第一次保持黄褐色的时间：此时已检测不到淀粉。
Repeat each pH at least three times with fresh reactants, and calculate a mean time.
每种pH至少用新的反应物重复三次，并计算平均时间。
Here is an example data set, made up for practice.
这是一组为练习编写的示例数据。
The starting starch and the end point were the same at every pH.
每种pH下初始淀粉量和终点都相同。
At pH five the mean time was one hundred and eighty seconds; at pH six, ninety; at pH seven, sixty; at pH eight, one hundred and twenty.
pH五时平均时间为一百八十秒；pH六时九十秒；pH七时六十秒；pH八时一百二十秒。
The last column gives the relative rate, one over the time.
最后一列是相对速率，即时间的倒数。
At pH seven, the mean end-point time is sixty seconds.
pH七时，平均终点时间为六十秒。
With the same starting starch and the same end point, one over the time compares how fast each reaction is.
初始淀粉量和终点相同时，时间的倒数可以比较各反应的快慢。
So rate equals one over t.
所以速率等于一除以时间。
One over sixty seconds is zero point zero one six seven per second.
一除以六十秒，得每秒零点零一六七。
That is a relative rate, not grams of starch digested each second.
这是相对速率，而不是每秒消化的淀粉克数。
Using the table: which pH tested was fastest?
利用表格：测试的pH中哪个最快？
How many times faster is pH seven than pH six?
pH七比pH六快几倍？
And what goes on the graph's axes?
图的坐标轴应该标什么？
Compare the rates, not the times the wrong way round, and ask whether four results can give an exact optimum.
要比较速率，不要把时间的大小关系弄反；并想一想，四个结果能否确定准确的最适pH。
Pause and try it.
暂停并试着回答。
A time graph has a minimum at the fastest condition; a rate graph has a maximum.
最快条件在时间图上是最低点，在速率图上是最高点。
A full six-mark answer has a sequence: buffers, a controlled water bath, mixing and timing, fresh iodine samples every thirty seconds, and a clear end point.
完整的六分答案要有步骤顺序：缓冲液、控温水浴、混合并计时、每三十秒取新样品滴碘液，以及明确的终点。
It states at least two controls and explains why they isolate pH.
要写出至少两个控制变量，并解释它们为什么能使pH的影响单独显现。
And it processes the data: repeats, means, and rates from one over time, with units and a cautious conclusion.
还要处理数据：重复实验、求平均值、用时间的倒数求速率，写上单位，并得出谨慎的结论。
This is a flow model of the heart, not its real anatomy.
这是心脏的血流模型，不是真实的解剖位置。
The right side pumps blood to the lungs, and the left side pumps it to the rest of the body.
右侧把血液泵向肺，左侧把血液泵向全身。
The coronary arteries branch off the aorta and supply the heart muscle itself.
冠状动脉从主动脉分出，为心肌本身供血。
Name the blood vessels that carry blood to the lungs and back from them.
说出把血液送到肺和从肺运回的血管。
Trace the path from the right ventricle, round to the left atrium, and give each vessel with its direction.
从右心室出发，一直追踪到左心房，并写出每条血管及其方向。
Pause and try it.
暂停并试着回答。
To the lungs: vena cava, right atrium, right ventricle, pulmonary artery, then the lungs.
到肺：腔静脉、右心房、右心室、肺动脉，然后到肺。
To the body: pulmonary vein, left atrium, left ventricle, aorta, then the body.
到全身：肺静脉、左心房、左心室、主动脉，然后到全身。
Arteries carry blood away from the heart, and veins bring it back; the pulmonary vessels show why oxygen content is not the definition.
动脉把血液运离心脏，静脉把血液运回心脏；肺部血管说明了为什么不能用含氧量来定义它们。
In one full circuit, blood passes through the heart twice.
血液每循环一周，要两次经过心脏。
Why is the wall of the left ventricle thicker than the right?
为什么左心室的壁比右心室厚？
Name where each ventricle sends blood, then connect the muscle thickness to the pressure needed.
说出每个心室把血液送到哪里，再把肌肉厚度与所需压力联系起来。
Distance alone is not a full answer.
只说距离远不是完整答案。
Pause and try it.
暂停并试着回答。
The right ventricle sends blood through the lungs at a lower pressure.
右心室以较低的压力把血液送过肺。
The left ventricle sends blood all round the body at a higher pressure.
左心室以较高的压力把血液送往全身。
Its thicker muscular wall produces the stronger contraction this needs, and valves stop the blood flowing backwards.
它较厚的肌肉壁能产生所需的更强收缩，瓣膜防止血液倒流。
The left side pumps blood, not just oxygen.
左心泵出的是血液，而不只是氧气。
Where are the heart's pacemaker cells?
心脏的起搏细胞位于哪里？
Choose one chamber.
选出一个心腔。
The natural pacemaker cells are in the right atrium, and they control the resting heart rate.
天然的起搏细胞位于右心房，控制静息心率。
An artificial pacemaker corrects an irregular rhythm.
人工心脏起搏器用于纠正不规则的心律。
That is a different problem from blood supply: the coronary arteries bring oxygen and glucose to the heart muscle, and a pacemaker does not widen a blocked artery.
这与供血是不同的问题：冠状动脉为心肌输送氧气和葡萄糖，起搏器并不能扩张阻塞的动脉。
Match the treatment to the problem.
治疗方法要与问题相对应。
Arteries have thick muscular and elastic layers, so they withstand high pressure, and their recoil keeps the blood flowing.
动脉有厚的肌肉层和弹性层，能承受高压，它的回弹使血液持续流动。
Veins have a wider lumen, thinner walls and valves, so they return blood at low pressure and stop it flowing backwards.
静脉管腔较宽、管壁较薄，并有瓣膜，能在低压下把血液运回心脏，并防止倒流。
Capillary walls are one cell thick, giving a short diffusion path to the tissues.
毛细血管壁只有一层细胞厚，到组织的扩散路径很短。
Explain how an artery is adapted to its function.
解释动脉如何适应它的功能。
Name the muscular or elastic tissue, not just 'a thick wall', and explain how it resists pressure and recoils.
要说出肌肉组织或弹性组织，而不只是“壁厚”，并解释它如何承受压力和回弹。
Blood vessels have no cell walls.
血管没有细胞壁。
Pause and try it.
暂停并试着回答。
A thick muscular and elastic wall withstands the pressure the heart produces.
厚的肌肉和弹性管壁能承受心脏产生的压力。
The elastic tissue stretches as blood is pumped into the artery.
血液泵入动脉时，弹性组织被拉伸。
Between beats it recoils, which helps keep the blood flowing.
在两次心跳之间，它回弹，帮助血液持续流动。
A narrow lumen is a fair comparison with a vein, but it does not create the heart's pressure.
管腔窄可以作为与静脉的比较，但它并不产生心脏的压力。
Give two structural differences between an artery and a vein.
说出动脉与静脉在结构上的两个区别。
Make both comparisons explicit, and choose from the muscle, the elastic tissue, the lumen or the valves.
两个比较都要写明确，可以从肌肉、弹性组织、管腔或瓣膜中选择。
'Thicker wall' is less precise than naming the tissue layers.
“壁更厚”不如说出具体的组织层准确。
Pause and try it.
暂停并试着回答。
First: an artery has a thicker layer of muscle than a vein.
第一：动脉的肌肉层比静脉厚。
Second: an artery has a thicker elastic layer than a vein.
第二：动脉的弹性层比静脉厚。
A narrower lumen, or having no valves, are accepted alternatives.
管腔更窄或没有瓣膜，也是可接受的答案。
Two statements about pressure are not two structural differences.
两句关于压力的话并不等于两个结构上的区别。
In the lungs, oxygen diffuses into the blood and carbon dioxide diffuses into the air in the alveoli.
在肺里，氧气扩散进入血液，二氧化碳扩散进入肺泡中的空气。
Many alveoli give a large surface area.
大量的肺泡提供很大的表面积。
Thin alveolar and capillary walls give a short diffusion path.
肺泡壁和毛细血管壁很薄，扩散路径短。
Blood flow carries the gases away and keeps the gradients steep, and breathing replaces the air in the alveoli to keep them steep too.
血液流动把气体运走，维持陡峭的浓度梯度；呼吸不断更新肺泡中的空气，也维持了梯度。
Models of the blood's components, not to scale.
血液成分的模型，没有按比例绘制。
Red blood cells have a pale centre, which is a dip in the cell, not a nucleus.
红细胞中央颜色较浅，那是细胞的凹陷，不是细胞核。
White blood cells have a nucleus.
白细胞有细胞核。
The small dark dots are platelets, which are fragments of cells.
小的深色点是血小板，它们是细胞碎片。
Blood is a tissue.
血液是一种组织。
Plasma is its liquid part, carrying dissolved glucose, carbon dioxide, urea, hormones and heat.
血浆是它的液体部分，运输溶解的葡萄糖、二氧化碳、尿素、激素和热量。
Red blood cells contain haemoglobin, have no nucleus and a biconcave shape, and carry oxygen.
红细胞含有血红蛋白，没有细胞核，呈双凹形，运输氧气。
White blood cells have a nucleus, and either engulf pathogens or produce antibodies.
白细胞有细胞核，能吞噬病原体或产生抗体。
Platelets are cell fragments that help blood clot, reducing blood loss and keeping pathogens out.
血小板是细胞碎片，帮助血液凝固，减少失血并阻止病原体进入。
Give two adaptations of a red blood cell, and explain the function of each.
说出红细胞的两个适应性特征，并解释每个特征的作用。
Each mark needs a complete pair: feature and function.
每一分都要有完整的一对：特征加作用。
Pause and try it.
暂停并试着回答。
Having no nucleus leaves more room for haemoglobin, which binds and carries oxygen.
没有细胞核，可以容纳更多血红蛋白，血红蛋白与氧结合并运输氧。
The biconcave shape gives a large surface area, for quick uptake and release of oxygen.
双凹形提供很大的表面积，使氧气能快速吸收和释放。
Each complete feature-and-function pair earns one mark, two marks in total.
每一对完整的特征与作用得一分，共两分。
Real exam data on a coronary artery.
这是关于冠状动脉的真题数据。
With no blockage, the blood flow is one hundred cubic centimetres per minute.
没有阻塞时，血流量为每分钟一百立方厘米。
At ten percent blockage it is sixty-four; at twenty percent, forty-two; at fifty percent, eight; and at eighty percent, only two.
阻塞百分之十时为六十四，百分之二十时为四十二，百分之五十时为八，百分之八十时只有二。
Describe the relationship between the percentage blockage and the blood flow.
描述阻塞百分比与血流量之间的关系。
Name both variables and how each changes.
说出两个变量以及它们各自如何变化。
Does twenty percent blockage mean only twenty percent less flow?
阻塞百分之二十是否意味着血流量只减少百分之二十？
Check the data.
查看数据。
Pause and try it.
暂停并试着回答。
The exam’s short trend answer does not establish a general flow equation.
考试中的简短趋势答案并不建立通用血流方程。
A coronary artery is partly blocked.
一条冠状动脉部分阻塞。
Explain the effect on the body.
解释它对身体的影响。
Connect the blood flow to the supply of oxygen and glucose, then follow it through respiration to the contraction of the heart.
把血流量与氧气和葡萄糖的供应联系起来，再一步步推到呼吸作用和心脏收缩。
A list of symptoms alone misses the explanation.
只列出症状并没有解释。
Pause and plan your answer.
暂停并构思你的答案。
A narrowed coronary artery reduces blood flow to the heart muscle, so less oxygen and glucose reach it.
冠状动脉变窄，流向心肌的血液减少，到达心肌的氧气和葡萄糖也减少。
Less aerobic respiration releases less energy in the heart muscle cells.
有氧呼吸减少，心肌细胞释放的能量减少。
With less energy, contractions can weaken, so less blood is delivered to the body's tissues.
能量减少会使心脏收缩减弱，输送到身体组织的血液也减少。
Exercise raises demand, so the poor supply can cause tiredness, breathlessness or chest pain.
运动时需求增加，供应不足就可能导致疲劳、气喘或胸痛。
Explain how a stent treats coronary heart disease.
解释支架如何治疗冠心病。
Give the physical mechanism, then the consequence for blood flow and supply.
先写出物理作用机制，再写出对血流和供应的影响。
'It unblocks it' on its own is not enough.
只写“它把血管疏通了”是不够的。
Pause and try it.
暂停并试着回答。
A stent opens the narrowed artery, or holds it open.
支架撑开变窄的动脉，或使它保持张开。
More blood can flow, bringing more oxygen and glucose to the heart muscle.
更多血液能够流过，为心肌带来更多氧气和葡萄糖。
But a stent does not stop fatty deposits building up again, and fitting one carries the risks of a procedure.
但支架并不能阻止脂肪再次沉积，而且植入支架本身也有手术风险。
Evaluate stents against statins as treatments.
评价支架与他汀类药物这两种治疗方法。
Explain one benefit and one limitation of each, and consider whether they can be used together.
分别说出每种方法的一个好处和一个局限，并考虑二者能否同时使用。
Do not pick an outright winner without evidence about the patient.
没有患者的具体信息时，不要直接判定哪个更好。
Pause and plan it.
暂停并构思。
A stent holds the artery open, improving blood flow straight away, but the procedure has risks and new fatty deposits can still form.
支架使动脉保持张开，能立即改善血流，但手术有风险，而且仍可能形成新的脂肪沉积。
A statin lowers cholesterol and slows the build-up of fatty deposits, but it means taking medication long term, with possible side effects.
他汀类药物降低胆固醇，减缓脂肪沉积，但需要长期服药，并可能有副作用。
They work differently, and can be combined.
二者作用方式不同，可以联合使用。
If an artery needs blood flow improved urgently, a stent may help most.
如果动脉急需改善血流，支架可能最有帮助。
To slow further deposits, lowering cholesterol with a statin helps.
要减缓进一步的沉积，用他汀类药物降低胆固醇会有帮助。
The right choice depends on how severe and urgent the problem is, and on the patient's circumstances.
正确的选择取决于病情的严重程度和紧急程度，以及患者的具体情况。
An evaluation weighs these trade-offs; it does not just name the treatments.
评价要权衡这些利弊，而不只是列出治疗方法。
A faulty valve, which may narrow or leak, can be replaced with a biological or mechanical valve; that means surgery, and mechanical valves need anticoagulant drugs.
有缺陷的瓣膜可能变窄或渗漏，可以用生物瓣膜或机械瓣膜替换；这需要手术，而且机械瓣膜需要服用抗凝药。
Severe heart failure may need a transplant, with a shortage of donors, a risk of rejection and immunosuppressant drugs.
严重的心力衰竭可能需要心脏移植，但供体短缺，有排斥风险，还要使用免疫抑制药物。
An artificial heart can keep blood pumping while a patient waits, with risks of infection and clots.
人工心脏可以在患者等待移植时维持泵血，但有感染和血栓的风险。
And bypass surgery redirects blood around a blocked coronary artery.
搭桥手术则让血液绕过阻塞的冠状动脉。
Bypass surgery sends blood around the blockage, and it is an accepted answer here.
搭桥手术让血液绕过阻塞处，这是可接受的答案。
A transplant or an artificial heart is for severe heart failure, not for every stent that fails.
心脏移植或人工心脏用于严重的心力衰竭，而不是每一次支架失败。
Match each problem to its own mechanism: a narrowed artery, a faulty valve, or a problem with the rhythm.
每种问题都要对应它自己的机制：动脉变窄、瓣膜缺陷，或心律问题。
Define health, for one mark.
给健康下定义，一分。
Then give one way a physical illness can affect mental well-being.
然后说出身体疾病影响心理健康的一种方式。
Include both physical and mental well-being, and give a specific interaction.
定义要包括身体和心理两方面，并举出一种具体的相互影响。
Pause and try it.
暂停并试着回答。
Health is the state of physical and mental well-being.
健康是身体和心理都良好的状态。
The two interact: a severe physical illness can contribute to depression.
二者相互影响：严重的身体疾病可能导致抑郁。
Diet, stress and life situations affect well-being too, so being free of disease is not a full definition.
饮食、压力和生活处境也会影响健康，所以没有疾病并不是完整的定义。
Diseases can interact.
疾病之间会相互影响。
A defect in the immune system makes infections more likely.
免疫系统缺陷使人更容易受感染。
Some viruses living in cells can trigger cancer.
某些寄居在细胞中的病毒可能引发癌症。
An immune reaction after an infection may trigger allergies.
感染后的免疫反应可能引发过敏。
And a severe physical illness may lead to depression.
严重的身体疾病可能导致抑郁。
An interaction is a connection between conditions, not just a list of diseases.
相互影响是指病症之间的联系，而不只是疾病的清单。
Diet, smoking and lack of exercise raise the risk of cardiovascular disease.
饮食、吸烟和缺乏运动会增加心血管疾病的风险。
Obesity is a risk factor for Type 2 diabetes.
肥胖是二型糖尿病的风险因素。
Alcohol affects the liver and the brain.
酒精影响肝脏和大脑。
Smoking causes lung disease and lung cancer.
吸烟导致肺部疾病和肺癌。
Smoking and alcohol in pregnancy can harm the unborn baby.
孕期吸烟和饮酒会伤害胎儿。
Carcinogens and ionising radiation cause cancer.
致癌物和电离辐射会导致癌症。
A risk factor raises the chance of disease; it does not make it certain.
风险因素增加患病的可能性，但并不意味着一定会患病。
Two questions that run in opposite directions.
两道方向相反的问题。
First, name a proven risk factor for Type 2 diabetes.
第一，说出二型糖尿病的一个已被证实的风险因素。
Second, name a disease linked to obesity.
第二，说出一种与肥胖有关的疾病。
Pause and try both.
暂停并试着回答这两题。
For the first: obesity is an established risk factor for Type 2 diabetes.
第一题：肥胖是二型糖尿病公认的风险因素。
For the second: Type 2 diabetes is a disease linked to obesity, and Type 1 is not accepted.
第二题：二型糖尿病是与肥胖有关的疾病，一型糖尿病不被接受。
Not everyone with obesity develops Type 2 diabetes, and not every case has the same causes.
并不是每个肥胖的人都会患二型糖尿病，每个病例的原因也不尽相同。
A risk factor is not a diagnosis.
风险因素不等于诊断。
Real exam data from seven countries: the mean sugar intake in grams per person per day, and an obesity rate.
这是七个国家的真题数据：人均每天摄入的平均糖量（克），以及肥胖率。
Notice the obesity rate is in arbitrary units, not a percentage.
注意肥胖率用的是任意单位，而不是百分比。
Country G has the highest sugar intake, one hundred and ninety-two grams, and the highest obesity, thirty-two.
G国的糖摄入量最高，为一百九十二克，肥胖率也最高，为三十二。
Complete the scale and the axis label, plot the points for countries C to G, and draw a line of best fit.
补全刻度和坐标轴名称，描出C到G国的点，并画出最佳拟合线。
What belongs on each axis?
每条坐标轴应该标什么？
Should every point be joined in order?
是否应该按顺序把每个点连起来？
Read the units before plotting.
描点前先看单位。
Pause and try it.
暂停并试着做。
Two scatter graphs, redrawn for this lesson.
两幅为本课重新绘制的散点图。
The left one uses the seven-country exam table, and the right one uses the practice data on towns.
左图使用七国的真题表格，右图使用关于城镇的练习数据。
The dashed lines show the fitted trends.
虚线表示拟合的趋势。
Put mean sugar intake, in grams per person per day, on the horizontal axis, and the mean obesity rate, in arbitrary units, on the vertical axis.
横轴为人均每天平均糖摄入量（克），纵轴为平均肥胖率（任意单位）。
Plot one point per country, on even scales that include every value.
每个国家描一个点，刻度要均匀并包括所有数值。
Then draw the overall trend: do not join the points country by country, or force the line through the origin.
然后画出总体趋势线：不要逐个国家连点，也不要强迫直线经过原点。
Practice data from three towns: the percentage of adults who are obese, and the number of people with diabetes per thousand.
三个城镇的练习数据：成年人肥胖的百分比，以及每千人中的糖尿病患者人数。
Town A: twelve percent and fourteen per thousand.
A镇：百分之十二，每千人十四人。
Town B: twenty-one percent and thirty-one per thousand.
B镇：百分之二十一，每千人三十一人。
Town C: thirty percent and forty-eight per thousand.
C镇：百分之三十，每千人四十八人。
Describe the relationship in the town data.
描述城镇数据中的关系。
Is it right to say the diabetes rate roughly doubles from town A to town C?
说糖尿病发病率从A镇到C镇大约翻了一倍，对吗？
Name both variables and the direction, then compare forty-eight with fourteen, using their units.
说出两个变量及变化方向，再带着单位比较四十八和十四。
Pause and try it.
暂停并试着回答。
The rate is about 3.4 times as high; the increase is 34 per 1000, not 34 percentage points.
发病率约为3.4倍；增加34/1000，不是34个百分点。
Explain whether obesity is a cause of Type 2 diabetes.
解释肥胖是否是二型糖尿病的原因。
What can this table, on its own, establish?
仅凭这张表能得出什么结论？
Separate established scientific knowledge from this one data set, and think about other ways the towns might differ.
把公认的科学知识与这一组数据区分开，并想一想这些城镇在其他方面可能有什么不同。
Pause and try it.
暂停并试着回答。
From prior knowledge: obesity is an established risk factor that causes Type 2 diabetes.
根据已有知识：肥胖是导致二型糖尿病的公认风险因素。
But this table of three towns only shows an association; it cannot isolate obesity's contribution.
但这张三个城镇的表格只显示了相关性，无法单独分离出肥胖的作用。
Age, diet, activity and sampling might differ between the towns, and a known mechanism does not rule those out.
各镇的年龄、饮食、活动量和抽样方式可能不同，已知的机制并不能排除这些因素。
A survey is used to claim that an energy drink causes heart disease.
有人用一项调查来宣称某种能量饮料会导致心脏病。
Give two checks you would make, each with a reason.
说出你会做的两项核查，并各给出理由。
How were the groups chosen and compared?
各组是如何选取和比较的？
Could another factor explain both the drinking and the disease?
是否有另一个因素能同时解释饮用和患病？
Pause and try it.
暂停并试着回答。
First, check the comparison: account for age, smoking, diet and exercise, which could explain both the drink choice and the disease risk.
第一，核查比较：要考虑年龄、吸烟、饮食和运动，这些因素可能同时影响饮料选择和患病风险。
Second, check the sampling: a small or biased sample could mislead.
第二，核查抽样：样本太小或有偏差都可能产生误导。
Each check earns a mark, and its linked reason another, so two pairs make four marks.
每项核查得一分，对应的理由再得一分，两对共四分。
Timing, independent repeats and a tested mechanism are other valid checks.
时间顺序、独立重复研究和经过检验的机制也是有效的核查。
An association shows two variables change together, but not which causes which, or how.
相关性表明两个变量一起变化，但不能说明谁导致谁，也不能说明机制。
A plausible mechanism suggests how an effect could happen, but not that this survey isolated it.
合理的机制说明效应可能如何发生，但不能说明这项调查已把它单独分离出来。
Repeated controlled comparisons rule out competing explanations, though not with certainty for every person.
反复的对照比较能排除其他解释，但不能保证对每个人都适用。
Peer review gives independent scrutiny of the methods, but does not prove cause by itself.
同行评审对方法进行独立审查，但它本身不能证明因果关系。
Look for evidence that converges.
要寻找相互印证的证据。
Give two differences between benign and malignant tumours.
说出良性肿瘤与恶性肿瘤的两个区别。
Compare whether each stays contained or invades, then compare whether it spreads to other parts of the body.
先比较它们是局限在一处还是侵入周围，再比较是否扩散到身体其他部位。
Size alone does not identify a malignant tumour.
仅凭大小不能判断肿瘤是否恶性。
Pause and try it.
暂停并试着回答。
A benign tumour stays in one area, usually inside a membrane, and does not invade other parts of the body.
良性肿瘤局限在一个区域，通常包在一层膜内，不会侵入身体其他部位。
A malignant tumour invades neighbouring tissues, and its cells can spread in the blood to form secondary tumours.
恶性肿瘤会侵入邻近组织，它的细胞可以随血液扩散，形成继发性肿瘤。
Cancer comes from changes in cells that cause uncontrolled growth and division.
癌症源于细胞的变化，导致不受控制的生长和分裂。
Explain how smoking can cause lung cancer, naming the substances involved.
解释吸烟如何导致肺癌，并说出其中涉及的物质。
Name the carcinogens, then link a change in DNA to the loss of control over cell division.
先说出致癌物，再把DNA的改变与细胞分裂失控联系起来。
Pause and try it.
暂停并试着回答。
Cigarette smoke contains carcinogens.
香烟烟雾中含有致癌物。
They can damage or mutate the DNA in lung cells.
它们会损伤肺细胞中的DNA或使其突变。
Changes that affect the control of cell division can lead to uncontrolled division, and to malignant tumours.
影响细胞分裂控制的改变，可能导致细胞不受控制地分裂，形成恶性肿瘤。
Not every mutation causes cancer, and some cancers also involve inherited risk factors.
并不是每个突变都会致癌，有些癌症还与遗传风险因素有关。
A model of a leaf in cross-section, not to scale.
叶片横切面的模型，没有按比例绘制。
The dots in the palisade cells are chloroplasts.
栅栏细胞中的小点是叶绿体。
The stoma is the pore between two guard cells, on the lower surface.
气孔是两个保卫细胞之间的小孔，位于叶片下表面。
A leaf is an organ: its tissues work together.
叶片是一个器官：各种组织协同工作。
The epidermis is the outer covering, with a waxy cuticle that protects the leaf and reduces water loss.
表皮是外层覆盖，表面有蜡质角质层，保护叶片并减少水分散失。
Palisade mesophyll has many chloroplasts for photosynthesis.
栅栏叶肉有许多叶绿体，进行光合作用。
Spongy mesophyll has air spaces between its cells, so gases can move.
海绵叶肉细胞之间有空隙，气体可以流动。
Guard cells control the width of the pores, balancing gas exchange against water loss.
保卫细胞控制气孔的大小，在气体交换和水分散失之间取得平衡。
Name three tissues: the one with the most chloroplasts, the one with many air spaces, and the tissue that can differentiate throughout the plant's life.
说出三种组织：含叶绿体最多的组织、有许多空隙的组织，以及在植物一生中都能分化的组织。
Give tissue names, in the order asked, not the names of single cells.
按题目顺序写出组织名称，而不是单个细胞的名称。
Pause and try it.
暂停并试着回答。
Palisade mesophyll has the most chloroplasts, for photosynthesis.
栅栏叶肉含叶绿体最多，进行光合作用。
Spongy mesophyll has the air spaces for gas movement.
海绵叶肉有供气体流动的空隙。
Meristem tissue, at the tips of roots and shoots, makes new cells that can differentiate throughout the plant's life.
分生组织位于根尖和茎尖，产生在植物一生中都能分化的新细胞。
Do not confuse meristem with mature xylem.
不要把分生组织和成熟的木质部混淆。
Why can water enter a root hair cell by osmosis, while some mineral ions need active transport?
为什么水可以通过渗透作用进入根毛细胞，而某些矿质离子需要主动运输？
Name what moves in each case, and compare the concentrations of the ion inside and outside.
说出每种情况下移动的是什么，并比较这种离子在细胞内外的浓度。
Pause and try it.
暂停并试着回答。
Water enters by osmosis, through a partially permeable membrane, from a dilute solution towards a more concentrated one.
水通过部分透性膜，以渗透作用从稀溶液进入较浓的溶液。
But a mineral ion may have to move from a lower concentration in the soil to a higher one in the cell.
但矿质离子可能要从土壤中的低浓度移向细胞内的高浓度。
That active transport uses energy released by respiration, and the root hair's large surface area helps uptake.
这种主动运输利用呼吸作用释放的能量，根毛的大表面积也有助于吸收。
Osmosis is the movement of water, not of ions.
渗透作用是水的移动，而不是离子的移动。
Xylem cells are dead and hollow, with no cytoplasm, while phloem sieve tubes are living, with some cytoplasm.
木质部细胞是死的、中空的，没有细胞质；而韧皮部筛管是活的，有少量细胞质。
Xylem walls are strengthened with lignin; phloem has end walls with holes, called sieve plates.
木质部细胞壁由木质素加固；韧皮部的端壁有孔，叫做筛板。
Xylem carries water and mineral ions, from the roots up to the stems and leaves.
木质部把水和矿质离子从根向上运到茎和叶。
Phloem carries dissolved sugars from where they are made to where they are used or stored, up or down.
韧皮部把溶解的糖从产生的地方运到利用或储存的地方，可以向上也可以向下。
These are the transpiration stream and translocation.
这分别叫蒸腾流和转运。
Compare xylem and phloem in structure and in function, for six marks.
从结构和功能两方面比较木质部和韧皮部，共六分。
Give paired structural differences, then compare what each carries and in which direction.
先成对写出结构上的区别，再比较各自运输的物质及方向。
A top answer covers both structure and function.
高分答案要同时包括结构和功能。
Pause and plan it.
暂停并构思。
Cells: xylem cells are dead and hollow, while phloem sieve tube cells are living and keep some cytoplasm.
细胞：木质部细胞是死的、中空的，而韧皮部筛管细胞是活的，保留少量细胞质。
Walls: xylem has lignin for strength, and phloem has end walls with holes, the sieve plates.
细胞壁：木质部有木质素加固，韧皮部有带孔的端壁，即筛板。
And one similarity: both form tubes for transport through the plant.
一个相同点：二者都形成管状结构，在植物体内运输物质。
Hollow xylem lets water flow, and lignin stops it collapsing under the pull.
中空的木质部使水能流动，木质素使它在拉力下不会塌陷。
Substances: xylem carries water and mineral ions; phloem carries dissolved sugars.
物质：木质部运输水和矿质离子；韧皮部运输溶解的糖。
Direction: xylem flows from the roots to the stems and leaves; phloem moves sugars from where they are made to where they are growing or stored, up or down.
方向：木质部从根流向茎和叶；韧皮部把糖从产生的地方运到生长或储存的部位，可以向上也可以向下。
Names: the water flow is the transpiration stream, and sugar transport is translocation.
名称：水的流动叫蒸腾流，糖的运输叫转运。
The sugar concentration is higher in the phloem than in a neighbouring cell, cell X.
韧皮部中的糖浓度高于相邻的细胞X。
Explain how structures inside the cells help move sugar into the phloem.
解释细胞内的结构如何帮助把糖运入韧皮部。
Start with mitochondria and respiration, then link the energy released to movement from low to high concentration.
从线粒体和呼吸作用讲起，再把释放的能量与从低浓度到高浓度的移动联系起来。
Pause and try it.
暂停并试着回答。
Cell X contains mitochondria.
细胞X含有线粒体。
Aerobic respiration in them releases energy.
线粒体中的有氧呼吸释放能量。
The sugars must move from a lower concentration to a higher one, against the gradient.
糖必须从低浓度移向高浓度，逆着浓度梯度。
So active transport uses that energy to load the sugars into the phloem.
所以主动运输利用这些能量把糖装入韧皮部。
This is loading; translocation is the movement of sugar through the tissue afterwards.
这是装载过程；转运是之后糖在组织中的移动。
Liquid water evaporates from the moist walls of the mesophyll cells into the air spaces.
液态水从湿润的叶肉细胞壁蒸发到细胞间隙中。
The water vapour diffuses out through the stomata, down its concentration gradient.
水蒸气顺着浓度梯度，通过气孔扩散出去。
The water lost draws more liquid water up the xylem, from the roots through the stem.
失去的水分把更多液态水从根经茎沿木质部向上拉。
Liquid water does not diffuse into the outside air; water vapour does.
扩散到外界空气中的是水蒸气，而不是液态水。
A higher temperature usually raises the transpiration rate, because evaporation is faster.
温度升高通常使蒸腾速率加快，因为蒸发更快。
More air movement raises it, because humid air is swept away from the leaf.
空气流动增强使速率加快，因为潮湿的空气被从叶片周围吹走。
Brighter light raises it, because stomata usually open wider.
光照增强使速率加快，因为气孔通常开得更大。
Higher humidity lowers it, because the water vapour gradient is smaller.
湿度升高使速率减慢，因为水蒸气浓度梯度变小。
Each holds with the other conditions controlled and enough water available.
这些结论都要在其他条件受控、水分充足的情况下成立。
Why does more air movement increase transpiration?
为什么空气流动增强会使蒸腾作用加快？
Give a three-step explanation.
分三步解释。
What is removed from just outside the stomata, and how does that change the gradient?
气孔外面的什么被带走了？ 这如何改变浓度梯度？
Pause and try it.
暂停并试着回答。
Moving air sweeps away the humid air from just outside the stomata.
流动的空气把气孔外潮湿的空气带走。
That keeps the water vapour concentration gradient steeper.
这样水蒸气的浓度梯度保持得更陡。
So water vapour diffuses out faster, and the transpiration rate increases.
于是水蒸气扩散得更快，蒸腾速率加快。
Air movement changes the gradient outside; it does not supply energy.
空气流动改变的是外部的浓度梯度，并不提供能量。
Which combination of conditions gives the greatest transpiration rate?
哪种条件组合下蒸腾速率最大？
Choose one.
选出一项。
Then think of two conditions that would decrease the rate.
然后想出两种会使速率降低的条件。
Warm with low humidity: evaporation is faster, and the vapour gradient is steeper.
温暖且湿度低：蒸发更快，水蒸气梯度更陡。
Higher humidity, a lower temperature, still air or dimmer light can all decrease the rate.
湿度更高、温度更低、空气静止或光照较弱，都会使速率降低。
Do not reverse the effect of humidity.
不要把湿度的影响弄反。
These are the usual effects under controlled conditions; a plant short of water may close its stomata.
这些是受控条件下的一般效果；缺水的植物可能会关闭气孔。
This exam graph shows the width of stomata over a day, not the rate of water loss.
这幅考题图显示一天中气孔的宽度，而不是失水速率。
The solid line is the normal pattern; the dashed line is for low carbon dioxide in the air.
实线是正常情况，虚线是空气中二氧化碳浓度低时的情况。
Why is the normal pattern of opening, shown by the solid line, an advantage to the plant?
为什么实线所示的正常开闭模式对植物有利？
Link closing at night to saving water, and opening at midday to carbon dioxide and photosynthesis.
把夜间关闭与节约水分联系起来，把中午张开与二氧化碳和光合作用联系起来。
Pause and try it.
暂停并试着回答。
At night there is little or no light, so photosynthesis is limited, and nearly closed stomata reduce water loss.
夜间光照很弱或没有光，光合作用受到限制，几乎关闭的气孔减少水分散失。
At midday the light supports photosynthesis, and wider stomata let more carbon dioxide in.
中午光照充足，有利于光合作用，张大的气孔让更多二氧化碳进入。
Remember the graph measures the mean width of the stomata, in arbitrary units, not the transpiration rate.
记住，这幅图测量的是气孔的平均宽度（任意单位），而不是蒸腾速率。
How does the response shown by the dashed line help the plant survive when there is little carbon dioxide in the air?
虚线所示的反应如何帮助植物在空气中二氧化碳很少时生存？
Compare both how wide the stomata open and for how long, and name the process that needs carbon dioxide.
比较气孔张开的宽度和持续时间，并说出需要二氧化碳的过程。
Pause and try it.
暂停并试着回答。
In low carbon dioxide, the stomata open wider and stay open for longer.
在二氧化碳浓度低时，气孔张得更大，张开的时间也更长。
That lets more carbon dioxide in for photosynthesis, despite the low concentration outside.
这样即使外界浓度低，也能让更多二氧化碳进入，用于光合作用。
But opening wider and for longer can also increase water loss.
但张得更大、时间更长也会增加水分散失。
Opening changes the plant's access to carbon dioxide, not the concentration in the air.
张开气孔改变的是植物获得二氧化碳的机会，而不是空气中的浓度。
Suggest why having fewer stomata on the upper surface of a leaf is an advantage.
说明为什么叶片上表面气孔较少是有利的。
Think about exposure and water loss, then explain how gas exchange can still happen.
想一想暴露程度和水分散失，再解释气体交换如何仍能进行。
Pause and try it.
暂停并试着回答。
The upper surface is often more exposed to sunlight, heat and wind.
叶片上表面通常更多地暴露在阳光、高温和风中。
Fewer pores there limit water loss from that exposed surface.
那里气孔较少，可以减少从暴露表面散失的水分。
The stomata on the lower surface still let carbon dioxide in for photosynthesis, with less exposure.
下表面的气孔仍能让二氧化碳进入，用于光合作用，而且暴露较少。
The pattern varies with the species and how the leaf is held.
这种分布会因物种和叶片的朝向而不同。
This graph plots the total water lost against time.
这幅图表示失水总量随时间的变化。
What shows the volume lost, and what shows the rate at midday?
什么表示失去的体积？ 什么表示中午时的速率？
Read the label on the vertical axis, and use a tangent for the gradient at one moment.
读纵轴的名称，并用切线求某一时刻的斜率。
A running total need not peak when the rate does.
累计总量不一定在速率最大时达到峰值。
Pause and think.
暂停并想一想。
This plot shows only the given tangent line, drawn for this lesson, not the original measured curve.
这幅图只画出了题目给出的切线，是为本课绘制的，而不是原来的实测曲线。
Read its two marked points carefully.
仔细读出切线上标出的两个点。
Find the rate of water loss at midday, in cubic centimetres per minute and in standard form.
求中午时的失水速率，单位用立方厘米每分钟，并用科学记数法表示。
The tangent passes through one hundred and ninety cubic centimetres at eight o'clock and two hundred and thirty at three o'clock in the afternoon.
切线经过上午八点一百九十立方厘米，以及下午三点二百三十立方厘米这两点。
Subtract the volumes and the times, and convert hours to minutes.
分别求体积差和时间差，并把小时换算成分钟。
Pause and try it.
暂停并试着计算。
The change in volume is the second volume minus the first.
体积变化等于第二个体积减去第一个体积。
Two hundred and thirty minus one hundred and ninety is forty cubic centimetres.
二百三十减一百九十，得四十立方厘米。
The change in time is the second time minus the first.
时间变化等于第二个时间减去第一个时间。
Fifteen hours minus eight hours is seven hours.
十五点减八点，得七小时。
Use the tangent's points, not two points on the curved results line.
要用切线上的点，而不是曲线上的两点。
Seven hours times sixty is four hundred and twenty minutes.
七小时乘六十，得四百二十分钟。
Rate equals the change in volume over the change in time.
速率等于体积变化除以时间变化。
Forty cubic centimetres over four hundred and twenty minutes is zero point zero nine five two cubic centimetres per minute.
四十立方厘米除以四百二十分钟，得每分钟零点零九五二立方厘米。
In standard form, that is nine point five two times ten to the minus two.
用科学记数法表示，就是九点五二乘十的负二次方。
Why is the rate of water loss lower at midnight than at midday?
为什么午夜的失水速率比中午低？
Link stomatal opening to light or temperature.
把气孔开闭与光照或温度联系起来。
And would the total amount of water lost fall overnight?
另外，夜间失水总量会下降吗？
Pause and try it.
暂停并试着回答。
With less light and a lower temperature, the stomata are mostly closed.
光照减弱、温度降低时，气孔大多关闭。
Less water vapour leaves, so the rate of water loss is lower.
散失的水蒸气减少，所以失水速率较低。
The total keeps rising, just more slowly; water already lost does not come back.
总量仍在增加，只是增加得更慢；已经失去的水不会回来。
Always read the axis before explaining a graph.
解释图像之前，一定要先读坐标轴。
A potometer measures water uptake: in the same capillary tube, the distance the bubble moves in a given time compares uptake rates.
蒸腾计测量的是吸水量：在同一根毛细管中，气泡在一定时间内移动的距离可以比较吸水速率。
Use a sealed, water-filled apparatus, let the shoot adjust, change one factor, control the leaf area, time and everything else, and repeat.
装置要密封并充满水，让枝条先适应，只改变一个因素，控制叶面积、时间和其他因素，并重复实验。
But uptake is only a stand-in: the plant keeps or uses some water, so it is not exactly the water lost by transpiration.
但吸水量只是一个替代指标：植物会保留或利用部分水，所以它并不完全等于蒸腾失水量。
To get a volume, you also need the tube's cross-sectional area.
要得出体积，还需要知道毛细管的横截面积。
Final checklist. Order the organisation levels. Recite the enzyme table with sites and products, and explain lock and key and denaturing. Label the heart with all five vessels and double circulation. Give every blood component with its adaptation, and every CHD treatment with a benefit and a risk. Separate correlation from proven cause in risk data, and benign from malignant tumours. Name the plant tissues, contrast xylem with phloem, and list the four transpiration factors with directions.
最后清单：排出组织层级；背出酶表（部位、产物），解释锁钥与变性；标出心脏五条血管与双循环；每种血液成分配适应、每种治疗配利弊；风险数据区分相关与已证因果；区分良恶性；说出植物组织、对比木质部与韧皮部、列出蒸腾四因素及方向。