Have you ever wondered why different animals or pests have their particular(特定的) colors? Colors in them seem to be used mainly to protect themselves.

　　Birds, especially seagulls, are very fond of locusts, but birds cannot easily catch locusts because locusts change their colors together with the change of the color of crops. When crops are green, locusts look green. But when crops are ripe, locusts take on exactly the same brown color as crops have. Some other pests with different colors from plants are usually easily found and eaten by their enemies. So they have to hide themselves in terror(驚慌地) 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 coloring is to protect themselves. Bears, wolves and other beasts move quietly through forests. They are usually invisible to the eyes of hunters, because they have the color much like the barks of trees.

　　An even stranger 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 spreads over, its enemies cannot find it, and it immediately swims away. Thus, it has existed(存活) up to now though it is not powerful at all.

　　問題：

　　1.This passage is mainly about .

　　A.the protective coloration of animals and pests

　　B.how a certain sea fish protects itself

　　C.animals or pests can dye themselves different colors

　　D.the change of color in locusts

　　【參考答案】A

　　[考點(diǎn)]主旨大意題

　　【精析】A 文章開篇以問句“Have you ever wondered why different animals or pests have their particular colors?(你是否曾好奇為什么不同的動(dòng)物或害蟲有它們特定的顏色?)”引入主題，第一段第二句“Colors in them seem to be used mainly to protect themselves.”點(diǎn)明了主旨，即動(dòng)物或害蟲身上的顏色似乎主要是用來保護(hù)它們自己的，接下來以鳥類、蝗蟲、熊和狼等動(dòng)物為例證明了這一觀點(diǎn)。另外，第三段第一句“…the main use of coloring is to protect themselves.”再次呼應(yīng)主旨。故選A。

　　2. Locusts are but they are not easily wiped out by their enemies because .

　　A.beasts; they are dangerous to their enemies

　　B.pests; they take on the same color as crops

　　C.birds; they fly extraordinarily fast

　　D.animals; they are powerful enough

　　【參考答案】B

　　[考點(diǎn)]推理判斷題

　　【精析】B 根據(jù)第二段第一句“…but birds cannot easily catch locusts because locusts change their colors together with the change of the color of crops.”和第四句“Some other pests with different colors…”可知，鳥兒不容易抓到蝗蟲，因?yàn)榛认x會(huì)隨著莊稼的顏色而改變自己的顏色。一些和植物顏色不同的其他害蟲通常很容易被敵人發(fā)現(xiàn)并吃掉。此處是在對(duì)比蝗蟲(locusts)與其他和植物顏色不同的害蟲，根據(jù)常識(shí)也可推知蝗蟲是一種害蟲(pest)。故選B。

　　3. The pests that have different colors from plants usually appear at night because .

　　A.they have the habit of coming out in darkness

　　B.it's easy for them to destroy plants in darkness

　　C.birds take their rest when night comes

　　D.their enemies tell them to do so

　　【參考答案】C

　　[考點(diǎn)]推理判斷題

　　【精析】C 根據(jù)第二段最后兩句“Some other pests with different colors 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，一些和植物顏色不同的害蟲通常很容易被敵人發(fā)現(xiàn)并吃掉，所以為了生存它們不得不惶恐地藏起來，只在晚上出沒。由此可推知，和植物顏色不同的害蟲選擇在晚上出沒的原因是敵人(鳥兒)晚上要休息。故選C。

　　4. Bears and wolves have the same colors as barks of trees because .

　　A.they like brown or grey colors

　　B.they enjoy walking through forests quietly

　　C.the colors help prevent themselves from being noticed

　　D.they fear other beasts

　　【參考答案】C

　　[考點(diǎn)]事實(shí)細(xì)節(jié)題

　　【精析】C 根據(jù)第三段最后兩句“Bears, wolves and other beasts move quietly through forests. They are usually invisible to the eyes of hunters, because they have the color much like the barks of trees.”可知，熊、狼和其他野獸在森林中安靜地移動(dòng)，獵人的眼睛通常是看不到它們的，因?yàn)樗鼈兊念伾蜆淦な窒嗨?。故選C。

　　5. The fish mentioned in the last paragraph can survive up till now because .

　　A.it can run faster than its enemies

　　B.it can send out black liquid

　　C.it can change its skin colors

　　D.it is powerful

　　【參考答案】B

　　[考點(diǎn)]推理判斷題

　　【精析】B 根據(jù)最后一段最后三句“A kind of fish living in seas can send out a kind of very black liquid when it faces danger. While the liquid spreads over…though it is not powerful at all.”可知，一種生活在海洋中的魚在遇到危險(xiǎn)時(shí)可以釋放出一種很黑的液體，當(dāng)這種液體擴(kuò)散時(shí)，敵人就找不到它了，它就會(huì)馬上游走。盡管這種魚一點(diǎn)兒都不強(qiáng)大，但是它存活到了現(xiàn)在。由此可推知，這種魚之所以能存活至今是因?yàn)樗茚尫乓环N黑色的液體。故選B。