A kind of little cars may take the place of today's big ones many years later. If everyone drives such cars in the future, there will be less pollution in the air. There will also be more space for parking in cities, and the streets will be less crowded.
      The little cars of the future will cost less. Driving will be safer, too, since these little cars can go only 65 kilometers an hour. The cars of the future will be fine for going around a city, but they will not be useful for a long way. Little cars will go 450 kilometers before they need to stop for more gasoline (汽油). If big cars are still used with the small ones, two kinds of roads will be needed in the future. Some roads will be needed for the big, faster cars and other roads will be needed for the small, slower ones.

    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.

    Have you ever imagined going to other countries without your paper Passport? That will soon come true. And your paper passport will become history. You may use their new kind of passport

    It's reported that Australia will be the first country to use the cloud passport. With the cloud passport, you don't have to take a paper passport with you all the time. The cloud passport will have your name, photos and other information. And if you go to other countries, you can just check the information on the computer.

    When you take a paper passport with you, you might lose it. But with the cloud passport, you don't have to worry about that.

    Do you think the cloud passport is a great idea? Perhaps you will have it in the future, too.

    When we can see well, we do not think about our eyes often. It is only when we can not see perfectly that we come to see how important our eyes are.

    People who are nearsighted can only see things that are very close to their eyes. Many people who do a lot of close work, such as writing and reading, become nearsighted. Then they have to wear glasses in order to see distant things clearly.

    People who are farsighted face just the opposite problem They can see things that are far away, but they have difficulty reading a book unless they hold it at arm's length. If they want to do much reading, they most get glasses too.

    Other people do not see clearly because their eyes are not exactly the right shape. This, too, can be corrected by glasses. Some people'8 eyes become cloudy because of cataracts. Long ago these people often became blind. Now, however, it is possible to operate on the cataracts and remove them.

    When night fails, colors become fainter to the eyes and finally disappear. After your eyes have grown used to the dark, you can see better if you use the side of your eyes rather than the centers. Sometimes, after dark, you see a small thing to one side of you, which seems to disappear if you turn your head in its direction. This is because when you turn your head, you are looking at the thing too directly. Men on guard duty sometimes think they see something moving to one side of them. When they turn to look straight at it, they can not see it any more, and they believe they were mistaken. However, this mistake happens because the center of the eye, which is very sensitive in daylight, is not as sensitive as the sides of the eye after dark.

A tornado (龙卷风) is a kind of strong storm with air which moves in a circle quickly. They can move over 200 miles per hour and cause a lot of damage (损坏). As they move across the land, they can easily pick up cars, trucks, and even houses, and then throw them very far. It is important to find a safe place if a tornado gets close.

A safe place could be a basement ( 地下室) or the lowest floor. If you are in a home without a basement, try to find a first-floor bathroom or a small room without windows in the middle of your house. You should curl up (蜷缩) into a ball and cover your head and neck with your hands.

But there are some people who actually want to get close to tornadoes. They are scientists who want to learn more about tornadoes. One of the best ways to do this is to get as close as possible to the tornado. They use special tools to measure (测量) what is happening in and around a tornado.

One special tool is called a tornado probe ( 探测仪). Inside the tornado probe, there are sensors (传感器) to measure wind speed, temperature, pressure, and direction.

Some probes even have cameras, so the scientists can see and understand what it's like to be in a tornado.

To be able to get these measurements, the scientists have to get a tornado probe near or into a tornado. Scientists will try to guess where a tornado will go next. Then they drive to that location and put down the probe. If they do not guess correctly, they pick up their probe and try another place. If they are right, the tornado will go near or even right over the probe. Then they take all of the measurements

from the probe and use them to predict where future tornadoes may form (形成) and travel. And they can give people some warning to keep away from a dangerous tornado.