Question

　　Have you ever 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, but birds can't 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 themselves. Bears, wolves and other beasts move quietly through forests. They are usually invisible to the eyes of hunters, because they have the colour much like the barks（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.

(1) This passage mainly talks about ________.

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A．the change of colour in locusts

B．the protective colouration of animals and pests

C．how a certain sea fish protects itself

D．animals or pests can dye themselves different colours

(2) Locusts are ________ but they aren't easily wiped out by their enemies because ________.

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A．animals;they are powerful enough

B．beasts;they are dangerous to their enemies

C．pests;they take on the same colours as crops

D．birds;they fly very fast

(3) The pests that have different colours from plants usually appear at night because ________.

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A．their enemies can easily find them and eat them

B．they have the habit of coming out in darkness

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

D．birds take their rest when night comes

(4) Bears and wolves have the same colours as the barks of trees because ________.

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A．they fear other beasts

B．they like brown or grey colours

C．they enjoy walking through forest quietly

D．the colours help prevent themselves from being noticed

Answer 1

答案：B;C;D;D
解析：

(1) 据短文叙述的细节可知：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，故本题选B。 (2) 根据文章第二段：“…birds can't easily catch locusts because locusts change their colours together with the change of the colour of crops.”可知，鸟类很难抓到飞蝗是因为飞蝗能够随着庄稼颜色的改变而改变自己的颜色。所以答案为C。 (3) 文章第二段的“Some other pests with different colours…and appear only at night”得知，这样的虫子若在白天出来活动，易被鸟类捉住，故它们只好在晚上出来，此题选D。 (4) 根据文章第三段：“Bears, wolves and other beasts move quietly through forests. They are usually invisible to the eyes of hunters…”可知：熊和狼有着和树皮一样的颜色，是因为这些颜色能够帮助它们不被猎人注意到。所经答案为D。