Pollution

    Hundreds of years ago, life was much harder than it is today. People didn't have modern machines. There was no modern medicine, either.

    Life today has brought new problems. One of the biggest is pollution （污染）. Water pollution has made our rivers and lakes dirty. It kills our fish and polluted our drinking water. Noise pollution makes us talk louder and become angry more easily. Air pollution is the most serious kind of pollution. It's bad to all living things in the world.

    Cars, planes and factories all pollute our air every day. Sometimes the polluted air is so thick that it is like a quilt over a city. This kind of quilt is called smog（烟雾）.

    Many countries are making rules to fight pollution. Factories must now clean their water before it is thrown away, they mustn't blow dirty smoke into the air.

    We need to do many other things. We can put waste things in the dustbin and not throw it on the ground. We can go to work by bus or with our friends in the same car. If there are fewer people driving, there will be less pollution.

    Rules are not enough. Every person must help to fight pollution.

    With the development of science and technology, our daily life is becoming more colorful and more convenient .

    Rubbish is a major kind of environmental pollution. Each person produces about 2kg of rubbish a day. We are making waste products faster than nature can break them down. And we are using up resources(资源)faster than they can he replaced(取代).

    This adds up to trouble for the environment. Where does all that rubbish go? What can be done to help dispose of(处理)rubbish? How can we make less rubbish?

    Rubbish isn't just the smelly rotting fruits, vegetables or meat that we throw away(抛弃) in our homes Those are only a small part of all tile stuff we throw away. We create other kinds of waste, in construction, mining and in our factories.

    Did you ever wonder what happens to your rubbish? Most is burned(燃烧)or buried in landfills(垃圾填埋场). Less than a quarter of our waste is recycled(回收).

    With a population of 1.3 billion(十亿), rubbish is a big problem for China. Chinese city create around 148 million tons of rubbish every year. The amount is growing at around 10 percent each year.

    Once we used about 3 billion plastic shopping bags everyday in China. The result was a great waste of resources and serious pollution. So we did something about that. Now we use more cloth bags and shopping baskets when we shop.

    In the coming years China will build waste-to-energy plants in cities to clean up the rubbish. But there's a lot more that needs to be done. And you can play a role.

    We live on Earth. It's our home. But how much do you know about it? Let me tell you something about our Earth.

    The Earth is like a huge ball. Like the other seven planets, the Earth is running around the sun. It's the third nearest one to the sun. It takes the Earth about 365 days to run around the sun. At the same time, the Earth is going around itself. If you are in space, you can see lots of white clouds over the surface of the Earth. Through the clouds, you can see the blue colour of the oceans, and the brown colour of the land. About 70% of the Earth is covered(覆盖)with water.

    Why do we have day and night? When the half of the Earth is facing the sun, it's daytime. As the Earth turns, and this half is away from the sun, night is coming. And it's daytime(白天) for the other half.

    Scientists think that there has been life on earth for millions of years. However, we haven't found life on other planets yet. The earth is a planet and it goes around the sun. And there are seven other planets that also go around the sun. The sun and its planets are called the solar system. The solar system is a small part of the universe.

    Scientists have launched many spaceships to explore other planets in the solar system. Some spaceships have gone beyond the solar system. However, no one has discovered any life in space yet.

    Why has no one from other planets sent us a message? Have they tried to send information to us? With so many stars in space, are we alone, or is there life on other planets in space?