Our life has become easier and more colorful because of mobile phones and the Internet. However, a number of worrying problems have come along with them.

Many car accidents are caused by mobile phones. Some drivers use mobile phones to get on the Internet while driving. Looking at their mobile phones and not at the road, these drivers have become a danger to us all.

Many of the dangers of the Internet are well known. Children who visit websites without their parents‘' permission sometimes talk to elder people they don't know and put themselves in great danger. People with blogs sometimes post information of people they don't know on their websites without permission. Some people even use the Internet to get personal information that we do not want them to have.

    Mobile phone and the Internet safety tips：

Use a ‘hands-free' phone if you need to use a mobile phone when you drive.

     In difficult driving situations such as in rain or snow, do not use your phone at all.

     Do not make very important phone calls while driving. They take your attention (注意力) off the road.

     Tell your children not to talk with anyone they do not know on the Internet.

     In an embarrassing situation (尴尬场合), be careful with people around you.

Don't give out any personal information on the Internet.

    The earth is about 4,600 million years old. Modern man has lived on the earth for only 35,000 years, but during that time, we have changed our planet in many ways. Many of the things that we have done are good, but more are not good for the earth.

    Water pollution

    A lot of people, birds and fish die each day because of water pollution. Factories have polluted the land and the water. As a result, many river and lakes are now dead.

    Air pollution

    In big cities, factories, as well as cars, trucks and buses are the biggest cause of air pollution. Many people in cities now have bad health problems. For example, Mexico city used to be a beautiful sunny capital, but today it is almost covered by thick brown clouds.

    Soil pollution

    In order to have a good harvest, most of the farmers use chemicals too much on their fields. That's bad for the soil. But this kind of pollution is difficult to stop.

    Hope for the future

    These problems are very serious for our future, so all of us should do something to improve our environment. If we can stop pollution, our planet will become more and more beautiful and our health will be better. Let's be greener people.

    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.

    We can see walls everywhere in the world. But the Great Wall of China is the biggest of all. The Chinese call it "The Ten-Thousand-Li Great Wall". It is in fact more than 6000 kilometers long. It is 6～7 meters high and 4～5 meters wide. In most places, five horses or ten men can walk side by side along the top.

    When you visit the Great Wall, you can't help wondering how the Chinese people were able to build such a great wall thousands of years ago. Without any modern machines, it was really very difficult to build it. They had to do all the work by hand. It took millions of men hundreds of years to build it.

    The Great Wall has a history of over two thousand years. The men began to build the first parts of it around two thousand seven hundred years ago. Then QinShihuang had all the walls joined up. He thought that it could keep the enemy out of the country.

    Today the Great Wall has become a place of interest. Not only Chinese people but also people from all over the world come to visit it.