听第二篇短文,回答第16~20小题。
(
B
)16. What's the climate like in deserts?
A. It's cold and dry. B. It's awful. C. It's windy and rainy.
(
C
)17. What are scientists trying to do?
A. To plant more trees.
B. To bring water to the desert.
C. To make the desert into field land.
(
A
)18. Who can't change the desert in a short time?
A. Scientists. B. Farmers. C. Students.
(
C
)19. Why is more and more land becoming desert?
A. Because the earth is polluted.
B. Because the ecosystem is changed.
C. Because people are doing bad things to the earth.
(
A
)20. What's very important to dry places?
A. Small green plants and grass.
B. Small animals and grass.
C. A bit of rain.