根据短文内容，从短文后的选项中选出适当的选项补全短文。 The earth is about 4,600 million years old. We humans have liv

根据短文内容，从短文后的选项中选出适当的选项补全短文。
The earth is about 4,600 million years old. We humans have lived on the earth for only 35,000 years, but during this period we have changed our planet a lot in many ways. 1
All over the world, people have cut down millions of trees, so more and more kinds of animals and plants are disappearing. In big cities, cars and buses have polluted the air. Factories have also polluted the land and the water.
2 It is important to the earth. But now air pollution is destroying it and that has made a very big hole in the ozone layer (臭氧层). 3 This is very dangerous because it can cause cancer.
Carbon dioxide (CO2) in the air has increased a lot. 4 it has formed a blanket (毛毯) around the each. 5 This makes our earth become warmer and warmer. Therefore, this causes the level of the ocean to rise.
All these problems are very serious. We must do something to stop our earth from being polluted anymore.
A. The heat from the sun can' t escape, so the temperature is rising.
B. Too much harmful light from the sun passes through it and reaches the earth directly,
C. Some things we've done are very good for the earth while some are bad.
D. Around the earth, there’s a special kind of oxygen (O2) called ozone (O3).
E. It mainly comes from different kinds of burning materials.

解析：短文属于说明文。短文介绍了对地球造成破坏的两在问题：臭氧层被破坏和温室效应这，提倡大家保护地球。【小题1】综合理解题。承接上一句的“have changed our planet a lot in many ways.”，有积极影响和消极影响。【小题2】综合理解题。从下一句“a very big hole in the ozone layer”可和这里要介绍的是“臭氧层”。【小题3】综合理解题。承上启下，这里所说的是臭氧层被破坏的结果。【小题4】综合理解题。上一句提到CO2的增加，接着讲增加的原因及后果。【小题5】综合理解题。后一句讲“温室效应”，那么本句谈它形成的原因。

这下我知道了