1）如何保护环境已成为世界最大难题之一；

2）各种污染破坏环境，损害健康；

3）不要乱倒垃圾，乱排废水；

4）我们应该保护环境，使我们的家园更加美丽。

—_______. We don't have the same topic.

—He _______ for nearly twenty years.

A

    Air pollution is one of the most common types of pollution in the world nowadays. It is quite serious in many places, especially in big cities. It can do great harm to our environment such as making the earth warmer, causing acid rain or destroying the ozone layer. As for human beings, air pollution causes all kinds of breathing problems.

    There are several reasons for air pollution. Firstly, many cities have a lot of factories and there we need to make food, clothing and other things. Every year these factories pour millions of tons of smog into air. Secondly, power factories can also give out harmful air. For example, in 1986 there was a bad accident at a nuclear power station in Russia. A cloud of radiation crossed the whole Europe. It is said that 125,000 people died in Russia as a result of illnesses caused by this accident. Thirdly, there are more cars in cities now. Once they are out in the streets, they will take in fresh air and give out dirty gas. Besides, smoking cigarettes also makes air pollution worse as will as damaging(损害) our health.  

A: Hello, Kate! You look so happy. What happened?

B: Hi, Paul. I've got good news for us!

A: What is it?

B: Our teacher said she  take us to go on a school trip tomorrow.

A: Really? Where shall we go?

B: To the lake in the south of our town.

A: Oh, no. That's not a good place for a school trip.

B: Why do you say that?

A: Because the water in the lake  terrible. I went there last weekend.

B: I can  believe it. It used to be a beautiful place with flowers and grass, and the water in the lake was very .

A: But now everything has changed. There is only rubbish .

B: How terrible! Let's tell our teacher about it.

A: OK. Let's go.

提示：1、你周围的环境受到了哪些污染？2、它们都造成了什么后果？3、我们应该如何解决这些环境污染问题？

B

    All over the world in the twenty-first century, people can get new energy in many ways.

    Energy from the wind. People use the power of the wind．It is a clean source(来源) of energy, and there is lots of it. However, if the wind does not blow, there is no wind energy.

    Energy from the water. When water moves from a high place to a lower place, it has the power to make electricity. Waterpower produces enough energy for 40, 000 people in a town. Waterpower gives energy without pollution. However, people have to build dams(大坝) to use this energy, and building dams is very expensive.

    Energy from the earth. There is heat in the rocks under the earth. Scientists use the heat to make geothermal(地热的) energy. San Francisco gets half of the energy from geothermal power. This kind of energy is cheap, but it is only possible in a few places in the world.

    Energy from the sun. Solar panels(太阳能电池板) on the roofs of houses and buildings can turn energy from the sun into electricity. These panels can create enough energy to heat the whole house during winter. Solar power is clean and plentiful(丰富的), but when the weather is bad, it can't produce power．

—He asked Maria _______.