问题补充：
Napoga is a 12-year-old girl in Ghana(加纳)，Africa. It is hard for her family to get clean water. Every morning，she leaves home at half past five to get clean water for her family in a village far away. It takes her six hours to get enough clean water for daily cooking and drinking. She has no time to go to school or to play with her friends. Millions of people in the world are like Napoga. They can get enough clean water to keep healthy.
Earth Day is April 22. But on all other days，we must also remember it. The water we use is the most important natural resource(自然资源) on the earth.
Water covers 70% of the earths surface. But most of that is sea water. We can use it for very many things. Fresh water covers only 1% of the earths surface.
You probably feel lucky that your life isn as hard as Napogas. But that doesn mean you don have to worry about water. We all face serious water problems. One of them is water pollution. All kinds of things from cars，factories，farms and homes make our rivers，lakes，and oceans dirty. Polluted water is very bad for people to drink. And dirty water is bad for fish，too. Now, 34% of all kinds of fish are dying out.
How do cars and factories make our water dirty？First，they pollute the air. Then，when it rains，the rain water comes down and makes our drinking water dirty. Dirty rain，called acid rain(酸雨)，is also bad for plants，animals and buildings.
Scientists say that in 30 years，more than half of the people in the world won have enough clean water. We have to learn how to save more water for ourselves and our children. Here is some advice for saving water：
●Turn off the water while you brush your teeth. You can save as much as 450 liters(升) each month.
●Leaky taps(漏水的龙头) waste a lot of water. Fix them right away！
●You can easily cut your 10-minute showers in half----and youll be just as clean.
●When you wash dishes，don let the water run.
●Only wash clothes when you have a lot to wash. If your washing machine isn full，you e wasting water！
【小题1】On the earth，.A．sea water is more widely(广泛地) used than fresh waterB．there is very little water for our livingC．there is 71% of fresh waterD．we don need to worry about water【小题2】Acid rain .A．is only bad for living thingsB．can be produced in factoriesC．doesn do harm(伤害) to people，but its bad for plants，animals and buildingsD．doesn just do harm to human beings but to animals，plants and buildings【小题3】Which of the following wastes water？A．We need ten minutes if we want a clean shower.B．We should put in enough clothes when we wash them in washing machines.C．You can keep yourself clean by having a shower for five minutes.D．Don let the water run when we brush our teeth and wash dishes.【小题4】Whats the main idea of the passage？A．Something must be done to prevent water from being polluted.B．Clean water means much to human beings and living things around us.C．Its time to take care of the water we use.D．Water is the most important natural resource on the earth.B
答案：
(答案→)B
解析：
【小题1】根据文章内容“ Water covers 70% of the earths surface. But most of that is sea water. We can use it for very many things. Fresh water covers only 1% of the earths surface.”可知答案为B
【小题2】根据文章内容“the rain water comes down and makes our drinking water dirty. Dirty rain，called acid rain(酸雨)，is also bad for plants，animals and buildings.”可知答案为D
【小题3】根据常识内容可知答案为A
【小题4】根据文章大意可知答案为C
