Reading comprehension. 阅读理解.

　　Scientists are trying to make the deserts (沙漠) into good land again. They are learning a lot about them, but more and more land is becoming deserts all the time. Scientists may not be able to change the deserts in time.

　　Why is more and more land becoming deserts? People make deserts. They are doing bad things to the earth.

　　There isn't much rain in some places on the earth, but still they don't become deserts. Why? Because some green plants and grass are growing there and they are very important to dry places. Plants can let the hot sun not make the land even drier and let the wind not blow the land away. When a little rain falls, the plants hold the water. Without plants, the land can become a desert more easily.

Choose the best answer. 选择最恰当的答案, 用A, B, C或D表示, 填入括号内.

(1) Deserts ________.

[　　]

A．can get very little rain

B．never have any plants or animals in them

C．can all be turned into good land soon

D．are good places for people to live in

(2) Green plants are very important to dry places because ________.

[　　]

A．they don't let the sun make the land even drier

B．they make the deserts beautiful

C．they let the wind blow the land away

D．they can keep the water

(3) Land is becoming desert all the time because ________.

[　　]

A．plants can't grow there

B．there is not enough rain

C．people are doing something wrong to it

D．both B and C

(4) Which is the main idea of the first paragraph?

[　　]

A．Scientists know nothing about the deserts.

B．Land is becoming desert faster than people can stop it.

C．Scientists have changed all the deserts into good land.

D．It's easy to change desert into land.

(5) After reading the passage we will know that ________.

[　　]

A．plants can stop dry land from becoming desert

B．it is good to cut down all the plants in the desert

C．all places without much rain will become desert

D．it is better to grow crops on dry land than to grow grass