福建省莆田市第二十五中学2015-2016学年高一下学期第一次月考 英语试题
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，并在答题卡上将该项涂黑。
A
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 and 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 the 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 there. In northern Europe, there is a kind of mice. 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, scientists have studied the migration of a kind of lobsters（龙虾）. Every year, when the season of 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.
21. The mice in northern Europe move when __________ .
A. they give birth B. the weather is bad
C. the place gets too crowded D. they haven’t enough food
22. The lobsters move __________ .
A. to the fresh water B. to the sea floor
C. at a certain time D. to find more food
