题目内容：

The earth’s valuable rain forests are in danger. They are getting smaller and the situation is becoming worse. This problem influences the whole world.

Rain forests are the natural habitat for many rare and beautiful animals, birds and insects. There’re various plants as well. For example, the Amazon rain forest in Brazil has a richer plant life than anywhere else on the earth. Some of the plants there are important for medical science. Aspirin, a drug which reduces fever and kills pain, is made from tree bark. Cough medicine can be produced from tree resin. Perhaps they may help us cure disease such as cancer and AIDS one day.

It is a great pity that the rain forests are disappearing.             There are two reasons. In many countries the trees have been cut down because the land is needed for animals and crops. In other parts of the world the trees are cut down because their wood is wanted. This wood is used by local people for firewood, or is sold to Japan, Europe and North America. It is used for buildings or made into furniture there.

The soil in the forests is indeed very thin. Without trees and plants, it is easily washed away by the rain or blown away by the wind. Soon nothing can be grown on it and the rain forests then become useless. In addition, the forests cannot produce O2 or absorb CO2. This leads to the greenhouse effect(温室效应), which makes the earth hotter and hotter.

When the forest is destroyed, it is not only the trees that are lost, the homes of millions of animals are destroyed too. Also kinds of animals are in danger—fish, reptile, birds, mammals, insects and shellfish—as well as thousands of plants. If we do not act immediately to save our rain forests, some of them will be gone.

1. The rain forests are in danger because ______.

A. a lot of medicine and furniture factories are built there

B. the greenhouse effect increases the earth’s temperature

C. the trees and the land are often destroyed for some reasons

D. large numbers of animals and plants there are disappearing

2.Which is the best sentence for the blank in Paragraph 3?

A. Why is it a pity?

B. How do they take place?

C. Why is this happening?

D. How are they disappearing?

3.The underlined word “this” refers to the fact that ______.

A. the earth in rain forests is actually poor

B. nothing can be grown in the rain forests

C. the earth is washed away or blown away

D. the forests fail to make O2 or take in CO2

4.The best title for this passage is ______.

A. Save the rain forest

B. Rain forests on the earth

C. Make full use of rain forests

D. Situations in the rain forest