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

    To grow,  plants need several 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) everywhere are almost not covered by trees or grass.

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

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

    What will happen if we try to make things grow on the sandy beach? A few plants, such as beach grass, will grow in sand, but most plants won't. Even if 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 plant food.

A

      There are too many cities around the world. And each city needs water in many ways. Water on Earth falls mainly as rain. So the rainfall (降雨量) is important to each part of the world. And it is different from one city to another. The following chart shows the average (平均的) rain fall in four different cities in July and January.

      Mobile phones are very popular with people. They are becoming smaller and more convenient.

Now the scientists in Canada made a smartphone (智能手机）from electronic paper. The PaperPhonc is flexible. People can control it by bending it or writing on it with a pen.

      Though the PaperPhone is only millimeters (毫米）thick, people can do many things with it. For example, people can use it to make phone calls, read books, watch movies and play music. So many people use it as a computer.

The scientists think there will be no paper in the office. And people can store what they want in the PaperPhone.

The scientists from Queen's University in Kingston, Canada said the PaperPhone would be in style in the future. It may be the end of paper and printers.

To make people be interested in this kind of mobile phones, the scientists will make it more beautiful. People will see the PaperPhone on May 10th this year.

    Noise pollution is doing much harm to our health now. Noise，in fact，is unwanted sound and is a kind of invisible (无形的) killer. More and more students enjoy listening to music very much. When they listen to MP3 players, they like to turn up the volume (音量). Some people love listening to loud music. Furthermore, while watching TV, they keep the volume up. But they haven't realized that the noise is weakening their hearing. In fact, the noise not only influences each member in the family, but also makes a difference to the comfort of neighbors.

    Noise pollution is a source of increasing misery (痛苦) to people in our society. If people are often disturbed by it, they may feel uncomfortable or upset. What's worse, the noise can make people mad sometimes. If a worker works in a printing factory for too long, his/her hearing loss is much faster than a common person working in a quieter environment. So everybody must pay more attention to noise pollution. Generally speaking，the following four types of noise should be watched out for：

    Noise in the street

    Construction site (建筑工地) noise

    Noise at work

    Transportation noise

    I think the local department (部门) should take measures to control the noise levels, but it's everybody's duty to keep a quiet environment.