Scientists are trying to make the desert into good land (陆地) again. They want to bring water to the desert, so people can live and grow food. They are learning a lot about the desert. But more and more of the earth is becoming desert all the time. Scientists may not be able to change the desert in time (及时). Why is more and more land becoming desert? Scientists think that people make desert. People are doing bad things to the earth. Some places on the earth don't get much rain. But they still (仍然) don't become desert. This is because (因为)green plants are growing there. Small green plants and grass () are very important to dry places. Plants don't let hot sun make the earth even drier (更干燥) . Plants don't let the wind blow the dirt (小土) away. When a little bit of rain falls, the plants hold the water. Without plants, the land can become desert much more easily.

1.[单选题]Scientists are trying to make ______ into good land again.
  • A.rivers
  • B. lakes
  • C.desert
2.[单选题]They want to bring ______ to the desert.
  • A.trees
  • B.animals
  • C.water
3.[单选题]Scientists think that ______ make desert.
  • A.people
  • B.plants
  • C. animals
4.[单选题]Some people on the earth don’t get much ______.
  • A.sun  
  • B.wind
  • C.rain
5.[单选题]Without ______, the land can become desert much more easily.
  • A.sun
  • B.wind
  • C.plants
参考答案: C,C,A,C,C