题干
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. 【小题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.
【小题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）.【小题3】 This is very dangerous because it can cause cancer.
Carbon dioxide （CO2） in the air has increased a lot. 【小题4】 It has formed a"blanket （毛毯）”around the earth. 【小题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.
根据材料内容,从下面六个选项中选出能填入文中空缺处的最佳选项。使短文意思通顺,内容完整。| 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．Around the earth there's a special kind of oxygen （O2） called "ozone" （O2）. |
| D．Some things we've done are very good for the earth while some are bad. |
| E．It mainly comes from different kinds of burning materials. |
| F．We get the heat from the sun. |
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