C
Look at the earth from space. Why does our planet look so blue? 20. Water is not just an important part of our planet. It is an important part of our body, too. More than half of our total body weight is water.
21. That's why we need to drink plenty of water every day. We drink water. We use it to cook and clean. Farmers use it to grow vegetables and crops like rice and corn. 22.
After the 1950s, people in the world need more and more water. 23. Scientists worry about it. They think there may not be enough water for us in the near future. What can we do to help? Use water wisely and stop polluting it.
Right now, ships and factories are putting wastes and even chemicals into seas, rivers and so on. It can make a lot of clean water dirty. 24. We must do something to stop it and let more people know about the importance of clean water. That's the best way to protect the earth, water and our future.
根据材料内容，从下面五个选项中选出能填入材料空缺处的最佳选项，使材料意思通顺、内容完整。
A. As we all know, our body loses water when we exercise or go to the toilet.
B. But there is not as much water as years before.
C. Because water covers almost 71% of the earth's surface.
D. It can also kill fish and other water-living lives.
E. Factories use it to make all kinds of things.

C
20. C 21. A 22. E 23. B 24. D