2 . As most people know, in the last few years, sandstorms have swept across many cities and areas of North China, polluting the air and disturbing daily lives of human beings. People look dirty and suffer many kinds of illnesses, such as breath difficulty. The sandstorm is such a serious problem that it has not only weakened the industrial and agricultural development of our country but also caused a lot of trouble to the living conditions of the Chinese people.

Therefore, effective measures should be taken as soon as possible to stop its happening. So how should we deal with the frightening sandstorms?

Some experts offer practical advice as follows: For one thing, more money ought to be put into tree planting and forest protection in order to keep more water on the Earth. For another, government of all countries should make laws on environment protection. For example, banning the use of throw-away chopsticks and punishing illegal tree cutting. Scientists should also study and find ways to lower the grade of its destruction and to improve the environment. As for some schools, education about sandstorms should be spread properly and timely to make more and more people attach great importance to this problem.

How people look forward to sunny days with soft wind touching their faces now and forever! The golden days can come back so long as we try our best to protect the natural environment from today on. And the fact is that what I expect is not just a dream. There are some sweet fruits from the early efforts.

3 . Yosemite is a national park in California. It is very beautiful and big. The park includes more than 760,000 acres in the California Mountains. Most of the park is wilderness.

The part of Yosemite that everyone likes is Yosemite Valley. It is a tiny valley that is 7 miles long and less than 1 mile wide. It has tall rock walls and streams that splash down in waterfalls. More than two million visitors come to the valley each year.

One ranger (守护人) says the number of visitors is more than the land can handle. The valley has 4,500 camping spots. It has a hotel that can hold 4, 000 families. This is still not enough to handle all of the visitors. The valley has grown so big that it has a lot of traffic and crime.

A worker says the park is trying to keep the beauty of the park and let everyone visit. Some areas have been fenced off from people and planted with seeds to try to keep them beautiful.

A former worker thinks Yosemite should get more money to take better care of the park. He would also like to teach people what the park service is trying to do.

Some people are trying to save Yosemite Valley. A plan has been made to get rid of some buildings. There will be fewer cars allowed inside the park. More buses will help get people around.

4 . It is the year 3000. I come to a place where I can’t see any water, plants or animals but black clouds in the sky and sand everywhere. It’s very dry so I drink some water that I carry with me. A native sees what I do and asks “What is it?” I pour some water and tell him it’s called water. “Oh, I’m so lucky that I can see water!” the man shouts in an excited voice. “You have never seen water? But how can you live without water?” I ask.

“Harry, get up, it is 7 o'clock, or you will be late!” a voice comes to my ears. “Oh! What a strange dream I dreamed just now!”

In class, I always think of that dream. And I also think of the fresh air, clean water, blue sky, green plants and animals in our world nowadays. How beautiful our life is!

But in order to make more money, people have built more and more factories. These factories send out waste smoke and water with chemicals which are harmful to the environment. The pollution is becoming worse and worse, and as a result, some animals and plants die out. With the development of agriculture, farmers spray aerosol (喷雾) and fertilizer, which also pollute the water and air. In the street the cars and buses are sending out heavy smoke which pollutes the air badly. Even tourism is harmful to the environment. When some tourists travel somewhere, they throw the plastic bags and rubbish onto the ground.

These behaviors are polluting the environment and the environment will become the greatest problem of the world. We shouldn’t pollute the environment any more. Otherwise more and more animals and plants will disappear. And maybe my dream will come true in the future.