（) a car on an icy road, the brake must be used gently.

people to see the animals, but small cage is not a good place for an animal to live in.

Today zoos keep animals in different kinds of cages. The cages are very big and open. They usually have plants and a little lake. The cages look like the animals' habitats.

Zoos help to protect all kinds of animals. They protect animals in the zoo and they protect animals in the wild. How do they do this? Zoos teach people how animals live in the wild. Zoos want people to help protect the animals' wild habitats.

Many plants and animals are going extinct. Mammoths, which are related with Asia elephants, are now extinct. There are no mammoths in the world today. Scientists say that seventy-four different kinds of living things go extinct every day!

Zoos are working together to stop animals from going extinct.

36. Zoos kept animals in small cages so that people can _____.

A. protect them

B. see them better

C. feed them

D. save them

37. Today, zoos keep animals _____.

A. in bigger cages

B. at home

C. in smaller cages

D. in the forest

38. To protect animals, zoos _____.

A. are trying to keep all kinds of animals

B. are trying to free the animals

C. teach people more about animals

D. want people to feed the animals

39. A mammoth is a kind of _____ that has gone extinct.

A. plant

B. bird

C. animal

D. tree

40. An animal or a plant that is going extinct _____.

A. has more and more living members

B. comes into this world soon

C. becomes very dangerous

D. has fewer and fewer living members

A.with

B.of

C.in

D.by

out English, but maybe he can't speak English.

If you want to know how to swim, you must get into the (32)and if you want to be a football (33), you must play football.

So you see, you can learn English only by (34) it. You must listen to your teacher in class. You must read your lessons every day. You must speak English to your classmates and also you must write something sometimes. Then one day, you may find your English very (35).

A. river B. good C. player D. using E. learn

A.got stuck on

B.got stuck for

C.got stuck in

D.got stuck to

A.When

B.At

C.In

D.On

此题为判断题(对，错)。

A.没有任何作用

B.提高传输速度

C.降低信号干扰的程度

D.降低成本

A.网络

B.广播

C.电视

D.印刷术

A.传输媒体是数据传输系统中在发送器和接收器之间的物理通路;

B.双绞线只能用于数字传输而不能用于模拟传输;

C.光纤系统的传输带宽远远大于其它媒体的带宽;

D.卫星通信具有较大的传播时延。

A.误码

B.端到端时延

C.线路故障

D.网络拥塞