There are many wetlands in China and some of them have become the world's important wetlands. The Chinese Yellow Sea Wetlands are among them. They are in Yancheng, Jiangsu Province. They are home for many different kinds of animals. The world's largest Milu Deer Nature Reserve is in them. More than 700 Milu deer live freely there. There are not many red-crowned cranes in the world, but every winter you can see some in the Red-crowned Crane Nature Reserve in the Yellow Sea Wetlands.

The temperature in the wetlands is usually neither too high nor too low. There is a lot of rain and sunshine, too. They are really good places for wildlife. Offering(提供) food and home for some special kinds of animals is not the only reason why we need to protect wetlands. Wetlands are important because they also prevent flood. But some people want to change the wetlands to make more space for farms and less space for wildlife.

    Luckily, more and more people are beginning to realize the importance of wetlands and wildlife. Every year, on February 2nd, many activities are held to tell people more about wetlands.

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    Imagine the situation. You are driving along a desert or on a mountain. You have no idea where you are. You passed the last house two hours ago. Then your car breaks down. It is night and it is cold. You have no mobile phone. What do you do? Well, next time take a GPS with you. This invention may be able to help you. It is a device(装置) which uses satellites (卫星) to find the user's position(位置). It can find your position to within 20 metres. A GPS cannot start your car, but at least you will know where you are.

    GPS, which means Global Positioning System, is a small radio receiver. It looks like a mobile phone. You can hold it in your hand, or put in your pocket. It is sometimes put into a watch or a telephone. We also find GPS devices in cars, planes, or boats. Some of these devices have electronic maps, so you know where you are. For example, in a city they can tell you the name of the street.

    There are three parts to the Global Positioning System. The first part is the receiver. You can hold it in your hand, or have it fixed into your car, plane, etc. The second part is a group of satellites orbiting the Earth. The receiver contacts at least four of the satellites and calculates(计算) its position. The third part of the system is a network of ground stations. They are all over the world. They control the satellites and make sure they are working well.

    Some people think that in the future the GPS will be as common as the mobile. They are becoming cheaper and more and more accurate(精确的). There are also new uses for the GPS. Perhaps they will become like watches. Everyone will have one and you will never be lost again.

    Canada Geese are large blue and white birds. When autumn comes, they have to fly south where the weather is warmer. The winters are so cold in Canada that the birds will die if they stay there.

Last spring, Bill Lishman found sixteen young Canada Geese on his farm. They had lost their parents. Bill thought, "These young birds won't know what to do in the autumn." He had a small plane and he decided to teach the birds to fly by following him. All through the summer, he went on short trips in his plane and the young geese flew after him.

When the cold weather arrived in the autumn, Bill flew to Virginia in the United States——600 miles South of his home in Canada. The geese followed him all the way. Bill left the geese in Virginia and he returned home.

    This spring, Bill was waiting for the birds to come back. They didn't arrive, so Bill flew to Virginia to get them. He looked for them for two weeks but he couldn't find them. When he arrived back home, he found the geese waiting for him. They had found their way home without him!

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    Can dolphins (海豚) talk? Maybe they can not talk with words, but they can talk with sounds. They show their feelings with sounds. Dolphins travel in a group. We call a group of fish a "school". They do not study, but they travel together. Dolphins are mammals (哺乳动物), not fish, but they swim together like fish in a school. Dolphins talk to the other dolphins in the school. They give information to the others. They talk when they are happy, sad or afraid. They say "welcome" when a dolphin comes back to the school. They talk when they play.

    They make some sounds above water. They make many more sounds under water. People cannot hear these sounds because they are very, very high. Scientists make tapes of the sounds and study them. Sometimes people catch dolphins for a large aquarium (水族宫). People can watch dolphins in a show. Dolphins do not like to be away from their school in an aquarium. They are sad and lonely. There are many stories about dolphins. They help people. Sometimes they save somebody's life. Dolphins' meat is good, but people do not like to kill them. They say that dolphins bring good luck. Many people believe this.