Question

  The earth is about 4. 6 billion years old. We humans 1      (live) on the earth for a long time,and we have changed our planet a lot in many ways. Some things we've done are very good for the earth 2        some are bad.

  Fewer trees All over the world,people have cut down 3       (million) of trees. When it rains or when the wind blows,the earth 4       (take) away. Forests have become deserts. So more and more sorts of animals and plants are disappearing.

  Traffic and factory pollution In big cities,cars and buses have polluted the air. Now many people in cities have health problems. Factories have also polluted the land and the water. As a 5       ,many rivers and lakes are now dead.

  The ozone layer (臭氧层) Around the earth,there's a special kind of oxygen (O₂) 6       (call) "ozone" (O₃) . It's important to the earth. But now air pollution is destroying it and that has made a very big hole in the ozone layer. Too much harmful radiation (辐射) from the sun passes 7        the hole and reaches the earth directly. This is very dangerous because this kind of radiation 8        cause cancer.

  More carbon dioxide (C0₂) Carbon dioxide in the air has increased a lot. It 9       (main) comes from burning oil,coal and wood. This has formed a "blanket" around the earth. The heat from the sun can't escape so the temperature is rising. That is called "the greenhouse effect (温室效应) ". 10       causes the level of the oceans to rise and the climate (气候) of the earth to change.

All these problems are very serious,so we must do something now.

1.        2.        3.        4.        5.         

6.        7.        8.        9.        10.       

Answer 1

1. have lived考查时态。人类在地球上已经生存了很长时间。

2. while考查连词。while在此处表示对比，可译为"而"。

3. millions考查数同。million表示不确切的数字时用复数且和of连用。

4. is taken考查被动语态。句意：下雨或刮风时，泥土被带走。

5. result考查固定短语。as a result意为"结果"。

6. called过去分词作后置定语，表示被动意义，表示"被称为"。

7. through 考查介词。从内部穿过用through。

8. can考查情态动词。句意:这很危险因为这种辐射会导致癌症。

9. mainly考查副词。mainly修饰动词come。

10. It考查代词。it在此处代替"温室效应"。