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We've all heard of mermaids. They are the beautiful half-human, half-fish creatures(生物). They have the head and body of a human and the tail of a fish. We also know that mermaids only exist in fairy tales. But where did all the stories about these creatures come from? If you have ever seen a manatee, then you might have an idea.
Manatees, which are also called sea cows, are mammals(哺乳动物) that live in the sea. Since they are mammals, they have to swim up to the surface to breathe air. Many people believe that the story of the mermaid began with the ancient sailors who saw the manatees putting their heads out of the water to breathe. Because manatees are upright when they do this, it looks like they are standing. If a sailor saw a manatee doing this from far away across the sea, it is possible that the sailor would mistake the manatee for a creature that is half-human, half-fish.
Mermaids are described as having very long hair. This is probably because manatees like to swim up to the surface of the water in areas where there is sea grass. Manatees eat all kinds of plants in the sea, including sea grass. The sea grass around the manatee's head when they eat could create a picture of long hair.

Manatees also have powerful tails that are very similar to the fish-like tail of a mermaid. The sailors probably watched manatees come up for air and then swim back below the surface, using their paddle-shaped tails. This would explain why the sailors thought mermaids had fish-like tails.

    The world itself is becoming much smaller by using modern traffic and modern communication equipment(通讯设备). Life today is much easier than it was hundreds of years ago, but it has brought new problems. One of the biggest is pollution. To pollute means to make things dirty. Pollution comes in many ways. We see it, smell it, drink it and even hear it. Man has been polluting the earth. The more people, the more pollution. Many years ago, the problem was not so serious because there were not so many people. When the land was used up or the river was dirty in one place, people moved to another place. They are slowly polluting the whole world.

    Air pollution is still the most serious. It's bad for all living things in the world but it is not the only one kind of pollution. Water pollution kills our fish and pollutes our drinking water. Noise pollution makes us angry more easily.

Many countries are making rules to fight against pollution. They stop people from burning coal in houses and factories in the city, and from putting dirty smoke into the air.

Pollution by SO₂ is now the most dangerous kind of air pollution. It is caused by heavy traffic. It is sure that if there are fewer people driving, there will be less air pollution.

    The earth is our home. We must take care of it. That means keeping the land, water and air clean. And we must take care of the rise in population at the same time.

    Smog(雾霾) is a big problem in many Chinese cities. But it seems that besides wearing a mask, few of us know what has caused the smog and what to do to beat it. Chai Jing, a former news hostess with China Central Television, discussed the questions in her documentary Under the Dome.

    The 103 - minute film was published on major Chinese video - sharing websites on Feb 28. In the film, Chai visits polluted places and talks to officials and scientists. She comes to the conclusion that burning too much coal and oil are the main causes of PM2.5 and smog.

    To make things worse, according to Chai, the coal and oil we are burning is of poor quality and don't meet the standards for environmental protection. Therefore they have produced more harmful gas to pollute the air.

    To solve the problem, Chai suggests that we should clean our coal and oil or replace them with cleaner energy such as natural gas. In her film, Chai also pointed out that ordinary people can do something to help control smog too. For example, we live a greener life by using more public traffic. Or if we see things that could harm the environment, we can try to stop it. In one scene from the film, Chai sees a dirt mound in a building site exposed in the air, and asks the person in charge to cover it. When she sees a restaurant cooking without any suitable filter facilities, she calls the hotline 12369. The restaurant installed the filter a week later.

    Chen Jining, the new minister of environmental protection, praised Chai. "This film encourages ordinary people to care about the environment. This is what we need in the future. "

    We each have memory(记忆力).That's why we can still remember things after a long time. Some people have very good memories and they can easily learn many things by heart, but some people can only remember things when they say or do them again and again. Many of the great men of the world have got surprising memories.

    A good memory is a good help in learning a language. Everybody learns his mother language when he is a small child. He hears the sounds, remember them and then he learns to speak. Some children are living with their parents in foreign countries. They can learn two languages as easily as one because they hear, remember and speak two languages every day. In school it is not easy to learn a foreign language because the students have so little time for it, and they are busy with other subjects, too. But your memory will become better and better when you do more and more exercise.

    To protect the environment, we are on the way. Here are a few things we can do.

    Unwanted gifts? Give them away!

    Have you ever received a gift that you didn't like? Did you throw it away? If so, you can have another choice now. Two British companies hopes people will give away their unwanted gifts to them. And they will resell the gifts to raise money for the poor. In this way, the gifts can be refused and have a future life. And people can make a difference to the world.

    Wear the trousers that reduce(减少) pollution!

    A chemistry scientist and a fashion designer(时装设计师) have created a new kind of trousers. The trousers are made of a new material which can help reduce air pollution around us. Scientists have tested the material. The result shows that it isn't harmful to human. This new kind of trousers may appear at the market in two years. Professor Ryan said, "If thousands of people wear the trousers, the air quality will be improved."

    Plant trees with Felix

    Felix Finkbeiner, a 14-year-old German boy, is not famous as a child actor but an environment hero. At the age of 9, Felix got the idea that children could do something to protect the environment. So he started a club. Felix soon got support from children all over the world. Some of them have become his good friends. The club has an aim of planting 212 million trees. They have planted over 3.5 million trees all around the world. Felix said, "The answer to controlling global (全球的 ) warming is trees-lots of trees!”