Unit 2 Working the land第卷第一部分听力(略)第二部分阅读理解(共两节，满分40分)第一节(共15小题；每小题2分，满分30分)阅读下列短文，从每题所给的四个选项(A、B、C和D)中，选出最佳选项。AHave you wondered why different animals or pests have their particular colours？Colours in them seem to be used mainly to protect themselves.Birds，especially seagulls are very fond of locusts (蝗虫)，but birds cant easily catch locusts because locusts change their colours together with the change of the colour of crops.When crops are green，locusts look green.But when crops are ripe，locusts take on exactly the same brown colour as crops have.Some other pests with different colours from plants are usually easily found and eaten by their enemies.So they have to hide themselves in terror for lives and appear only at night.If you study the animal life in any part of the world，you will find the main use of colouring is to protect them.Bears，wolves and other beasts move quietly through forests.They are usually invisible (cant be seen) to the eyes of hunters，because they have the colour much like the bark(树皮) of trees.An even more strange act remains to be noticed.A kind of fish living in seas can send out a kind of very black liquid when it faces danger.While the liquid is over，its enemies cannot find it，and it quickly swims away.Thus，it has existed up to now though it is not powerful at all.21.This passage mainly talks about .A.the change of colour in locustsB.animals or pests can dye(染色) themselves different coloursC.how a certain sea fish protects itselfD.the protective colour of animals and pests 答案D解析主旨大意题。本文主要讲述了动物有效地避免天敌伤害的办法就是其外表的颜色随周围环境的变化而变化，呈现出一种保护色。故选D。 22.Locusts are pests but they arent easily wiped out by their enemies because .A.they change colours with the cropsB.they are dangerous to their enemiesC.they fly very fastD.they are powerful enough答案A解析细节理解题。根据第二段第一句“.but birds cant easily catch locusts because locusts change their colours together with the change of the colour of crops.”可知，鸟类很难抓到蝗虫是因为蝗虫能够随着庄稼颜色的改变而改变自己的颜色。故选A。23.The pests that have different colours from plants usually appear at night because .A.their enemies can easily find them and eat them B.they have the habit of coming out in darknessC.its easy for them to destroy plants in darknessD.birds take their rests when night comes答案A解析细节理解题。根据第二段最后两句“Some other pests with different colours from plants are usually easily found and eaten by their enemies.So they have to hide themselves in terror for lives and appear only at night.”可知，这样的虫子若在白天出来活动，它们的敌人会很容易发现并吃掉它们。故选A。24.A certain fish living in seas has lived through millions of year because .A.it is the most powerful in the sea B.no other fishes can swim as fast as it canC.it can send out a kind of liquid which makes its enemies unable to find itD.the liquid it sends out can kill its enemies答案C解析细节理解题。根据最后一段可知，这种鱼可以放出一种液体，这种液体可以让敌人找不到它们。故选C。BWhat will man be like in the futurein 5,000 or even 50,000 years from now? We can only make guesses，of course，but we can be sure that he will be different from what he is today，for man is slowly changing all the time.Let us take an obvious example.Man，even five hundred years ago，was shorter than he is today.Now，on average，men are about three inches taller.Five hundred years is relatively a short period of time，so we may assume that man will continue to grow taller.Again，in the modern world we use our brains a great deal.Even so，we still make use of only about 20% of the brains capacity.As time goes on，however，we shall have to use our brains more and more，and eventually we shall need larger ones! This is likely to bring about a physical change to the head，in particular the forehead，will grow larger.Nowadays our eyes are in constant use.In fact，we use them so much that very often they become weaker and we have to wear glasses.But over a very long period of time it is likely that mans eyes will grow stronger.On the other hand，we tend to make less use of our arms and legs.These，as a result，are likely to grow weaker.At the same time，however，our fingers will grow more sensitive because they are used a great deal in modern life.But what about hair? This will probably disappear from the body altogether in course of time because it does not serve a useful purpose any longer.In the future，then，both sexes are likely to be bald.Perhaps all this gives the impression that future man will not be a very attractive creature to look at! This may well be true.All the same，in spite of all these changes，future man will still have a lot in common with us.He will still be a human being，with thoughts and emotions similar to our own.25.Which of the following serves as the evidence that man is changing?A.Mans hair is getting thinner and thinner.B.Man has got stronger eyes now than he ever had.C.Man has been growing taller over the past 500 years.D.Mans arms and legs have become lighter and weaker.答案C解析细节理解题。根据第