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't 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 earth's surface. But most of that is sea water. We can't use it for very many things. Fresh water covers only 1% of the earth's surface.
You probably feel lucky that your life isn't as hard as Napoga's. But that doesn't mean you don't 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't 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 you'll be just as clean.
●When you wash dishes，don't let the water run.
●Only wash clothes when you have a lot to wash. If your washing machine isn't full，you're  wasting water！
【小题1】On the earth，_______.

Why do plants grow in some places and not in others? Why does some land have so much growing on it, while other land has almost no plants growing on it at all?

To grow, plants need several things. One is warmth. In very cold places almost nothing grows. Plants also need water. In very dry parts of the Earth only a few unusual plants can grow. That's why dry deserts everywhere are almost not covered by trees or grass.

Plants must also have a place in which to put down their roots and grow. They find it difficult to grow on hard land. The town is built on hard land. The plants here have only the soil found between the cracks of the stones to grow in.

Another thing plants must have before they can grow is food.

    What will happen if we try to make things grow on the sandy beach? A few plants, such as beach grass, will grow in sand, but most plants won't. Even if the weather is warm enough and we water the plants each day, many of them will die because the sand on this beach has almost no food for plants.

1.   According to the passage, plants need ______ things to grow well.

   A. two                    B. three                   C. four                          D. five

2. What does the underlined word "cracks" mean in the text?

   A. 缝隙                B. 表面                  C. 夹层                        D. 底部

3. From the passage, we can know it is           for plants to grow in dry places.

   A. easy                 B. difficult               C. impossible                 D. important

4. The reason why most plants can't grow on the sandy beach is that _______.

   A. there isn't enough sunlight                 B. there is too much water

   C. it is too crowded there                      D. it has little food for plants

6.   The passage can most probably be found in a ______book.

   A. science               B. history                     C. travel                       D. math

Many years ago，there were lots of trees on earth，because summer lasted a whole year．What was the forest like? It is not difficult to see，because parts of that ancient（古老的）forest still stand．It is the rainforest．Here，even in a sunny day water drops through the leaves．

Today's largest rainforest is in South America．It covers about a million square miles．All the trees are very tall；the young trees are nearly sixty feet high．But it is not easy for some to grow higher because very little sunlight leaches them．

Many trees are about 60 to 120 feet high．Some are even taller．The tallest trees can be 200 feet high．

In this forest of tall trees，plant life is rich，animal life is rich，too．At different heights live different animals and many different noises can let you know where they are．

根据短文内容，选择最佳答案。

1．There were lots of trees on earth many years ago because of the _________．

A．cold weather          B．largest forest          C．warm weather               D．rainforest

2．A rainforest has enough _________．

A．trees                    B．rainfall（雨量）      C．forest                    D．leaves

3．There is rainforest _________．

A．only in South America                              B．only in the old days

C．in some parts of the world                          D．below the sea

4．Young trees share little sunlight because _________．

A．tall trees are above them                           B．there isn't enough sunlight

C．they needn't much sunlight                          D．it is summer the whole year

5．You can always find different animals by _________．

A．their colors                                             B．the noises they make

C．climbing the trees                                       D．watching them carefully