Nearly all our food comes from the soil. Some of us eat meat, of course, but animals live on plants. If there were no plants, we would have no animals and no meat. So the soil is very necessary for life. The top of the ground is usually covered with grass or other plants. There may be dead leaves and dead plants on the grass. The waste matter(粪) from animals also falls on it.

    All soil needs food. If we do not give it any, the plants will be weak. Farmers found that animals' waste is the best food for the soil, but chemical fertilizers(化肥) are also very useful. The same crop（庄稼）should not be grown in the same place every year; it 's better to have a different crop. A change of crop and the use of a good fertilizer will keep the land good.

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

阅读短文回答问题。

    Drinking water is good for your health. There are some scientific ways of drinking water.

    ⒈It is the best medicine to drink two glasses of water in the morning.

    ⒉Drink clean water.

    ⒊Drink the water that has not been boiled.

Many people think boiled water is safe and good for people's health. In fact, it is not true. The boiling point of water is 100 ℃. By boiling it, most bacteria(细菌) in water can be killed. In the past, the water was less polluted, so boiling was a good way to make clean water. But heavy metals and other dangerous things in today's water are much more terrible than bacteria. Boiling doesn't solve that problem. And boiling water may give us more dangerous things in our glass.

    ⒋Never use soft drinks to take the place of water.

    ⒌Water is also needed in winter.

    ⒍Drink water at the right time.

    1) After getting up in the morning, you have less water in your body, because you weren't drinking for the whole night .So you should drink some water to keep your health after getting up in the morning. That can prevent high blood pressure(血压), cerebral hemorrhage(脑溢血) and so on.

    2) Drinking water at about 10 a. m. helps your body keep enough water.

    3) Drinking water at about 3 p. m. can clean the wastes out in your body.

    4) About eight o'clock in the evening is the best time to drink water. Your blood gets thicker when you sleep. Water will make your blood less thick.

    Besides, we should drink 2L of water every day. Water is so important in our life. We should drink water often.

    There are some easy things you can do to protect the environment and the earth. Choose ideas from' the list or come up with a few of your own.

    Plant flowers, grass and trees.

    Whenever you visit a park or a beach, take away what you bring there-keep rubbish in a bag until you can put it in a dustbin.

    Turn off the lights and TV sets when you leave the room. This saves a lot of electricity.

    Turn off the tap when you brush your teeth. You can save some water by not letting it run also, use a glass cup instead of a paper cup because this saves paper.

    Keep the doors and windows closed in winter to keep warm air in.

    Give your old books and magazines to a library instead of throwing them away.

    Give your old clothes to poor children you know instead of throwing them away.

    Use both sides of paper,

    Stop pouring dirty water into the rivers or lakes nearby.

    Encourage all your friends to do the same things you do to help protect the earth.

    You don't have to wait until Earth Day to do these things. Make every day Earth Day.

    If everyone makes a contribution to protecting the environment, the world will become much more beautiful.