Unit6 五年高考练
I.阅读理解
（2019天津，C）
How does an ecosystem（生态系统）work？What makes the populations of different species the way they are？Why are there so many flies and so few wolves？To find an answer, scientists have built mathematical models of food webs, noting who eats whom and how much each one eats.
With such models, scientists have found out some key principles operating in food webs. Most food webs，for instance，consist of many weak links rather than a few strong ones. When a predator（掠食动物）always eats huge numbers of a single prey（猎物），the two species are strongly linked；when a predator lives on various species，they are weakly linked. Food webs may be dominated by many weak links because that arrangement is more stable over the long term. If a predator can eat several species, it can survive the extinction(灭绝) of one of them. And if a predator can move on to another species that is easier to find when a prey species becomes rare, the switch allows the original prey to recover. The weak links may thus keep species from driving one another to extinction.
Mathematical models have also revealed that food webs may be unstable, where small changes of top predators can lead to big effects throughout entire ecosystems. In the 1960s, scientists proposed that predators at the top of a food web had a surprising amount of control over the size of populations of other species-including species they did not directly attack.
And unplanned human activities have proved the idea of top-down control by top predators to be true. In the ocean, we fished for top predators such as cod on an industrial scale, while on land, we killed off large predators such as wolves. These actions have greatly affected the ecological balance.
Scientists have built an early-warning system based on mathematical models. Ideally, the system would tell us when to adapt human activities that are
pushing an ecosystem toward a breakdown or would even allow us to pull an ecosystem back from the borderline. Prevention is key，scientists say，because once ecosystems pass their tipping point（临界点），it is remarkably difficult for them to return.
1.What have scientists discovered with the help of mathematical models of food webs？
A. The living habits of species in food webs.
B. The rules governing food webs of the ecosystems.
C. The approaches to studying the species in the ecosystems.
D. The differences between weak and strong links in food webs.
2. A strong link is found between two species when a predator _____.
A. has a wide food choice
B. can easily find new prey
C. sticks to one prey species
D. can quickly move to another place
3. What will happen if the populations of top predators in a food web greatly decline
A. The prey species they directly attack will die out.
B. The species they indirectly attack will turn into top predators.
C. The living environment of other species will remain unchanged.
D. The populations of other species will experience unexpected changes.
4. What conclusion can be drawn from the examples in Paragraph 4
A. Uncontrolled human activities greatly upset ecosystems.
B. Rapid economic development threatens animal habitats.
C. Species of commercial value dominate other species.
D. Industrial activities help keep food webs stable.
5. How does an early-warning system help us maintain the ecological balance
A. By getting illegal practices under control.
B. By stopping us from killing large predators.
C. By bringing the broken-down ecosystems back to normal.
D. By signaling the urgent need for taking preventive action.
Ⅱ.七选五
（2019课标全国Ⅱ）
Imagine a child standing on a diving board four feet high and asking himself the question: “Should I jump ” This is what motivation or the lack of it can do. Motivation and goal setting are the two sides of the same coin. 1 Like the child on the diving board，you will stay undecided.
2 More than that，how should you stay motivated to achieve the goal First，you need to evaluate yourself，your values，your strengths，your weaknesses，your achievements，your desires，etc. Only then should you set your goals.
You also need to judge the quality and depth of your motivation. This is quite important，because it is directly related to your commitment. There are times when your heart is not in your work. 3 So，slow down and think what you really want to do at that moment. Clarity（清晰）of thoughts can help you move forward.
Another way of setting realistic goals is to analyze your short and long term objectives，keeping in mind your beliefs，values and strengths. Remember that goals are flexible. 4 They also need to be measurable. You must keep these points in mind while setting your goals.
Your personal circumstances are equally important. For example，you may want to be a pilot but can’t become one because your eyesight is not good enough. 5 You should reassess your goals, and motivate yourself to set a fresh goal.
You will surely need to overcome some difficulties，some planned，but most unplanned. You cannot overcome them without ample motivation. Make sure that you plan for these difficulties at the time of setting your goals.
A. This can affect your work.
B. So how should you motivate yourself
C. However, this should not discourage you.
D. So why should we try to set specific goals
E. They can change according to circumstances.
F. Motivation is what you need most to do a good job.
G. Without motivation, you can neither set a goal nor reach it.
1. ______ 2. ______ 3. ______ 4. ______ 5. ______
Ⅲ.语法填空
（2017课标全国Ⅲ）
She looks like any other schoolgirl，fresh-faced and full of life. Sarah Thomas is looking forward to the challenge of her new A-level course. But unlike her school friends，16-year-old Sarah is not spending half-term 1 (rest). Instead，she is earning 6，500 a day as 2 model in New York.
Sarah 3 (tell) that she could be Britain’s new supermodel，earning a million dollars in the next year. Her father Peter，44，wants her to give up school to model full-time. But Sarah， 4 has taken part in shows along with top models，wants 5（prove）that she has brains as well as beauty. She is determined to carry on with her 6 （educate）.
She has turned down several 7 (invitation) to star at shows in order to concentrate on her studies. After school she plans to take a year off to model full-time before going to university to get a degree 8 engineering or architecture.
Sarah says, “My dad thinks I should take the offer now. But at the moment, school 9 (come） first. I don’t want to get too absorbed in modeling. It is 10 （certain) fun but the lifestyle is a little unreal. I don’t want to have nothing else to fall back on when I can’t model any more.”
1. _____ 2. _____ 3. _____ 4. _____ 5. _____
6. _____ 7. _____ 8. _____ 9. _____ 10. _____
参考答案：
Ⅰ.语篇解读：本文为说明文，主题语境为人与自然，主题语境内容为自然环境。地球上的生态系统是如何运转的呢？物种之间有的关系非常紧密，有的关系疏远，科学家用数学模型来弄清生态系统运转的奧秘。本文有助于培养学生的思维品质。
1. B 细节理解题。本题题干意为：在食物网数学模型的帮助下科学家们已经发现了什么？第二段第一句话（利用这种模型，科学家们已经发现了一些在食物网运行过程中的关键原则）与B项（影响生态系统食物网的规则）相符，故选B项。A：在食物网中物种的生活习惯。C：研究生态系统中物种的方法。D：食物网中关系疏远和关系紧密的区别。
2. C 细节理解题。本题题干意为：当一个捕食者______，我们会从两个物种之间找到一个紧密的关系。第二段第三句话（当一个捕食者总是大量吃一种猎物的时候，这两个物种之间就建立起了紧密的关系）与C项（坚持吃一个物种的猎物相符，故选C项。A：有广泛的食物选择。B：能很容易找到新的猎物。D：能很快迁徙到另一个地方。
3. D 推理判断题。本题题干意为：如果食物网顶端的捕食者数量大量减少，会发生什么事？根据第三段第一句（数学模型也揭示出食物网可能不稳定，顶端的捕食者的小小变化都会给整个生态系统带来巨大影响）可知，当食物网顶端的捕食者数量大幅度减少时，食物网中的其他物种的数量会受到意想不到的影响，故选D项。A：它们直接捕食的猎物物种会灭绝。文中没有提及会灭绝，排除A项。B：它们不直接捕食的物种会变成顶端捕食者。C：其他物种的生活环境会保持不变。
4. A 推理判断题。本题题干意为：从第四段的例子中我们可以得出什么结论？第四段中以人类在海洋中捕食顶端捕食者鳕鱼和在陆地上大量杀死顶端捕食者狼为例来解释说明第一句话。结合 These actions have greatly affected the ecological balance.可知A项（不受控制的人类活动极大地打乱了生态系统）与此相符，故选A项。B：快速的经济发展威胁到了动物的栖息地。C：具有商业价值的物种控制了其他物种。D：工业活动有助于保持食物网稳定。这三项文中均没有信息提及。
5. D 推理判断题。本题题干意为：一个早期的警报系统会如何帮助我们保持生态平衡？根据最后一段的描述：这套预警系统可以告诉我们什么时候调整将生态系统推向崩溃的人类活动或甚至能将生态系统从崩溃边缘拉回。预防是关键，一旦生态系统超过了临界点那就非常难恢复了。D项（这套系统通过发出紧急信号来让我们采取预防措施）与此相符，故选D项。A：通过控制非法行为。B：通过阻止我们捕杀大型捕食者。这两项文中没有信息提及。C：通过把遭到破坏的生态系统拉回到正常状态。预警系统本身不能做到这一点，它只能给人类发出信号。
Ⅱ.语篇解读：本文是说明文。主题语境是人与自我，主题语境内容为认识自我，完善自我。文章从介绍动机和目标开始，告诉我们如何确立正确的动机和目标对我们更有益。本文旨在培养学生科学认识自我、激励自我、辩证看待问题、合理解决问题的能力。
1. G 过渡句。句意：若没有动机，你既不能设定目标，也不能达成目标。由设空处上句话 Motivation and goal setting are the two sides of the same coin.（动机和目标的设定是一件事情的两个方面。）可知，动机是很重要的。根据设空处下句 Like the child on the diving board，you will stay undecided.知，中间需要加一个表示转折的句子：若没有动机……。故选G。
2. B 主旨句。句意：那么，你应该如何激励自己呢？该题中，设空处位于文章第二段开头，可能会是该段的主旨句。设空处后面的 how should you stay motivated to achieve the goal也是引出该段话题或是对主旨句的进一步说明。另根据句子结构一致的原则，可找到与此问句结构一致的选项B：So how should you motivate yourself？故选B。
3. A 过渡句。句意：这可能会影响你的工作。根据设空处前面的句子 There are times when your heart is not in your work.（有时你的心会不在你的工作上。）可知，接下来会说这样做的后果（影响你的工作）。设空处后面介绍正确的做法。故选A。
4. E 细节句。句意：它们可以根据情况来改变。设空处前面的句子提到 Remember that goals are flexible.（要记得目标是灵活的。），接下来可能会接着解释它们会改变。选项E中的They与上句话中的 goals指代一致。故选E。
5. C 过渡句。句意：然而，这不应该使你泄气。由设空处上句话中的 you may want to be a pilot but can’t become one because your eyesight is not good enough（你可能想成为一名飞行员，但因为你的视力不够好而不能成为一名飞行员）可知，接下来会告诉我们解决这个问题的办法。根据设空处下句话中的 You should reassess your goals（你应该重新评估你的目标）可知，选C项。
Ⅲ.语篇解读:本文为记叙文。Sarah现在是一名在校生，她还是一名兼职模特。她的父亲建议她放弃学业做一名专职模特，但她却做出了不同的选择。
1.resting 考查非谓语动词。固定结构 spend some time（in） doing sth花费时间做某事。
2.a 考查冠词。句意：相反，她现在在纽约作为一名模特，每天挣6，500英镑。mdel为可数名词，此处表示泛指，故填冠词a。
3. has been told/was told 考查时态和语态。句意：Sarh被告知她可以成为英国的一名超模新星，第二年就可以有一百万美元的收人。根据语境可知 Sarah与tell之间为被动关系，故用被动语态。此处既可以用一般过去时态表示过去发生的动作，也可以用现在完成时态，表示过去发生的动作对现在的影响。
4.who 考查定语从句。设空处引导非限制性定语从句，先行词为 Sarah，故填关系代词who。
5.to prove 考查非谓语动词。want to do sth，想要做某事。
6.education 考查词性转换。形容词性物主代词后面跟名词，故填 education。
7.invitations 考查名词复数。根据 several可知，此处应该填复数形式。
8.in 考查介词。a degree in...指“某专业的学位”，专业前用介词in。
9.comes 考查动词时态。由上下文语境以及时间状语at the moment可知，此处应该为一般现在时态，主语为第三人称单数，故填comes。
10.certainly 考查副词。设空处在句中作状语修饰形容词fun，故填副词。

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