题目内容：

    Like many other animals, swallows will fly south when the days turn cold and the leaves from trees begin to fall. They travel many miles to find a warmer________This type of travel is called migration (迁徙).

Birds are animals that like to migrate a lot when it is ________. About 600 out of 9,000 kinds of birds do it.They ________ in autumn and come back during the warm spring months.

Many birds don't like the cold. They need ________, but plants die and insects (昆虫) hide in winter. So,they'll only come home the next year, when there will be plenty of food for them to eat.But the________is often hard and not safe. Many birds fly in groups and make noises. Cranes (鹤) fly in groups like the________ “V”, or in a row. Others travel in pairs ________alone.

Some can travel a very ________ way. They fly between lands. For example, the Arctic tern (北极燕鸥) can travel 20,100 kilometres. They________a home near the North Pole, go to the Antarctic in autumn, and then come back in spring.Birds never________ .How do the birds find their way? They look at things like the sun, moon and stars. They are very clever,aren’t they?

1.A.winter B.summer C.autumn

2.A.hot B.dry C.cold

3.A.live B.leave C.harvest

4.A.water B.clothes C.food

5.A.trip B.time C.day

6.A.post B.word C.letter

7.A.but B.or C.and

8.A.dark B.long C.hard

9.A.look B.build C.decorate

10.A.get lost B.grow up C.give up