Why do plants grow in some places and not in others? Why does some land have so many plants growing on it, while other land has almost no plants growing on at all?

    To grow, plants need some things. One is warmth. In very cold places, almost nothing grows, Plants also need water. In very dry parts of the Earth, only a few unusual plants can grow. That's why dry deserts(沙漠）almost don't have trees or grass.

    Plants must also have a place in which to put down their roots（根）and grow. They find it difficult to grow on hard land. The town is on hard land. The plants here can only grow in the soil（土壤）between the cracks of the stones.

    Another thing plants must have before they can grow is food.

    What will happen if we try to make things grow on the sandy（有沙的）beach? A few plants, such as beach grass, will grow in sand, but most plants won't. Even if（即使）the weather is warm enough and we water the plants each day, many of them will die because the sand on this beach has almost no food for plants.

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    Rivers are one of our most important natural resources(资源). Many of the world's great cities are located on rivers, and almost every country has at least one river through it that plays an important part in the lives of its people.

    Since the beginning of history, people have used rivers for transportation. The longest one in the United States is the Mississippi. The lifeline of Egypt is the Nile. To the people of India, the Ganges is great, but it is also important for transportation. Ships can travel along it for a thousand miles. Other great rivers are the Congo in Africa and the Mekong in southeastern Asia. The greatest of all for navigation(航海), however, is the Amazon in Brazil. It is so wide and so deep that large ships can go about two thousand miles up it.

    Besides transportation, rivers give food, water to drink, water for crops, and chances for fun and recreation for the people who live along their banks. In order to increase the supply of water for crops, engineers sometimes build a dam(坝) across a river and let a lake form behind the dam. Then people can use the water not only to irrigate(灌溉) their fields but also to make electricity for their homes and industries.

    However, large cities and industries that are located on rivers often cause problems. As the cities grow in size and industries increase, the water in the rivers becomes polluted with chemicals and other materials. People are learning the importance, however, of doing more to keep their rivers clean if they want to enjoy the benefits of them.

    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. "

The Chinese language differs from Western languages in that, instead of an alphabet (字母表), it uses characters which stand for ideas, objects or deeds. Chinese words are formed by putting together different characters. In many cases, a single character can also make up a word. As one kind of the most ancient characters, Chinese characters have played an important role in the development of Chinese culture.

   ①    Chinese writing began thousands of years ago. According to an ancient story, a man named Cang Jie invented Chinese writing. One winter day while he was hunting, he saw the footprints of animals in the snow and noticed that the appearance of each one was different. Then he had the idea that he could use different shapes to represent different objects. The first Chinese characters were drawings of physical objects. Some characters have been simplified (简化) and others have been made more difficult over time.

   ②    However, as a whole, the characters have developed from drawings into standard forms. The character for a mountain was at first three mountaintops together. This became one mountaintop and three lines, and over time turned into the character used nowadays.

  ③     Sometimes to express ideas, some characters were made by combining two or more characters together. For example, "休" was made up of the characters for a man and a tree. The character "囚" was formed with a "man" inside a square. Other characters were developed for directions and numbers. It is easy to distinguish (区别) their meanings by looking at them, for example, the characters for "up" and "down", which are opposites of each other.

   ④    Though these kinds of characters indicate meanings, one of their shortcomings is that they do not show how they should be pronounced. Therefore, a method was developed to have one part of a character represent the meaning and the other suggest the pronunciation. Many Chinese characters used today were made this way.

In the 1950s, the Chinese government introduced simplified Chinese characters in the hope to make learning to read and write more understandable to the general population, which would increase literacy (读写能力) across the country. And now they have widespread use in China's mainland.

Hi, I'm Cindy. We know doing sports and eating good food can help us keep healthy. Do you have good eating habits? Now let me tell you what I eat every day. In the morning, I always have eggs. I eat baozi or mantou. I also eat porridge（粥）. My breakfast helps me start a day well. I have rice and vegetables for lunch. I eat ice-cream, too. But I don't eat too much, because I don't want to be fat. My favorite fruit is the apple. I usually eat an apple after lunch. In the evening, my mother cooks soup（煲汤）, fish and vegetables for our family. I like vegetables best because they can keep me healthy. Before I go to bed, I drink a glass of milk. It's good for my sleep. I also drink much water in the day. It's important（重要的） for me. There are few（很少的） calories（卡路里） in water. So I'm not fat now. 

The sad but beautiful music Erquan Yingyue is very popular in the world, as it could touch the hearts of people. Actually, music brings in more {#blank#}1{#/blank#} in life, and is very important to teenagers. Here are a lot of reasons. First, it helps teenagers express themselves well, and allow {#blank#}2{#/blank#} to connect with their emotions, thoughts, and experiences. Music also {#blank#}3{#/blank#} a sense of identity and belonging, as teenagers often use it to make friends with their peer groups. Besides, music is a source of entertainment to teenagers and helps them feel {#blank#}4{#/blank#}. It can keep them away from the stresses of daily life. In addition, music can inspire and motivate teenagers to influence their feelings and behaviors. It can even work as a way for teenagers to experience different cultures, widen their understanding {#blank#}5{#/blank#} the world. In all, music plays an important role in the lives of teenagers, providing with a sense of connection, creativity, and joy.