Question

阅读理解 　　We know that many animals do not stay in one place．Birds, fish and other animals move from one place to another at a certain time．They move for different reasons：most of them move to find food more easily, but others move to get away from places that are too crowded． 　　When cold weather comes, many birds move to warmer places to find food．Some fishes give birth in warm water and move to cold water to feed．The most famous migration(迁移)is probably the migration of fish, which is called “salmon”．This fish is born in fresh water but it travels many miles to salt water．There it spends its life．When it is old, it returns to its birthplace in fresh water．Then it gives birth and dies．In northern Europe, there is a kind of mouse．They leave their mountain homes when they become too crowded．They move down to the low land．Sometimes they move all the way to the seaside, and many of them are killed when they fall into the sea． 　　Recently(近来)，scientists have studied the migration of a kind of lobster(龙虾)．Every year, 　　when the season of the bad weather arrives, the lobsters get into a long line and start to walk 　　across the floor of the ocean．Nobody knows why they do this, and nobody knows where they go． 　　So, sometimes we know why humans and animals move from one place to another, but at other 　　times we don’t．Maybe living things just like to travel． (1) Most animals move from one place to another at a certain time to ________． [　　] A． give birth B． enjoy warmer weather C． find food more easily D． find beautiful places (2) The fish called “salmon” spends a long time in ________． [　　] A． salt water B． rivers C． fresh water D． its birthplace (3) The mice in northern Europe move when ________． [　　] A． they give birth B． the place gets too crowded C． the weather is bad D． they haven’t enough food (4) The lobsters move ________． [　　] A． to the fresh water B． at a certain time C． to the undersea D． to find more food (5) What is the main idea of the passage? [　　] A． Animals move to find food more easily． B． The migration of the fish called “salmon” is the most famous migration． C． Living things move from one place to another because they like to travel． D． Sometimes we know why and how living things move from one place to another, but sometimes we don’t．

Answer 1

答案：1．C;2．A;3．B;4．B;5．D;
解析：

(1)	起初一看，四个选项好像都在文中叙述过，但仔细分析题干中的“most animals”这一关键词语，便可排除其它选项．在第一段最后一句中可找到答案的出处．
(2)	有关“salmon”的情况在第二自然段中作了叙述．这种鱼出生在淡水中，后不到咸水地区居住，在那里度过一生中绝大部分时光．到老了以后又回到它出生之时的淡水之中．仔细分析题干中的“spend a long life”和短文中的关键句“There it spends its life．”便可断定答案为A．
(3)	“they leave their mountain homes when they become too crowded．”一句是答案的出处．
(4)	该题答案的出处是文章的第三自然段．文中说，龙虾是在海底成群结队游动的时间是每年天气不好的季节，目的及它们到哪里去谁也不知道，余项与文章叙述不符．
(5)	文中第二自然段叙述了“salmon”和北欧的一种老鼠迁移方向和原因；第三自然段叙述了龙虾的游动情况，但原因不知道．最后一段开头一句正是对本文主题的概括． 　　这篇短文讲述了某些生物的迁移这一自然现象，并分析了迁移的原因．科学家们最近又研究了龙虾海底成群结队迁移的现象．它们选择在每年天气不好的季节里进行迁移，其中的原因及迁移的目的，科学家尚未弄清楚．