Life will be different in the future, because many changes will come. But what will the changes be? Let's have a look now.

    Children will not use pens or books in the future. Every student will have a computer at school. Just use their computers and they will find everything they are interested in.

    People will wear a kind of clothes. They are made of newspapers. People don't have to wash them because the clothes won't get dirty.

    People needn't work for eight hours a day. They will have more free time for sports, watching TV and family trips.

    Robots will help people to clean the room. What's more, they can play chess with people, play the piano and talk to people.

    I think we will live a happy and healthy life in the future.

    On June 26th, 2000, two scientists, called Francis Collins and Craig Venter, told the world that they could now read the whole “map” of the human body: DNA. DNA is something that all humans have, and it tells the body what to do. DNA is the reason that we look like our mother and father, because we get some of their DNA to make our own. Now we can read some of this “map”, and so we can find out more about how our bodies work.

    People have been trying to understand the human body for a long time. In 1860, Gregory Mendel discovered that there is a special reason why we look the same as other people in our family. It is because of small things called “genes” that we have in our body. In 1953, James Watson and Francis Crick made another discovery and found out that those small parts are really messages written in the DNA with a special language.

    In 1961, Marshall Nirenberg and Johann Matthaei found the first “word” that they could understand in that language, showing how DNA tells the cell to build its parts. This meant that one day we would be able to read all the messages that a human body gets from its parents' bodies. Scientists have now found all the words in DNA map, but we still do not understand what they all do. By understanding what just one “word” means, we can help save people from several diseases. So the more we understand, the more doctors will be able to do.

    Most people hope that this will help to make better medicine and help people who are very ill. Other people worry about that when we learn more words and find out lots of other information, we still use it in the wrong way, just to make people more attractive, or stop sick people getting jobs.

We've talked about snails (蜗牛) and their slow move. But much of the time snails don't move at all. They're in their shells —sleeping .

    Hot sun will dry out a snail's body. So at the least sign of hot sun, a snail draws its body into its shell and closes the opening with a thin cover. Then it goes to sleep. A snail will die in a heavy rain. So whenever it rains, it goes inside its shell house and goes to sleep. A snail can sleep for as long as it needs to. It can take a short sleep. Or it can sleep for days at a time. And it spends all the winter months in its shell, asleep.

    In spring the snail wakes up. Its body, about three inches long, comes out of from the shell. When hungry, the snail looks for food. It can't see very well. Its eyes, at the ends of the top feelers are very weak. But its sense of smell is very strong. It helps the snail to the new greens. Then the snail's little mouth goes to work.

    A snail's mouth is no longer than the point of a pin(针). Yet it has 256,000 teeth! The teeth are so small that you can't see them. But they do their work. If you put a snail in a hard paper box, it will eat its way out. And if a snail wears out its teeth, it will grow new ones.

    Mostly, a snail looks for food at night .But on cloudy days it eats in the daytime. It eats all day long. A snail can go on eating for hours and never feel full.

    One of the hottest places on the earth is Death Valley. It's a desert valley in North America. The animals in Death Valley don't use technology to keep cool. They have special abilities that help them live there.

    The kangaroo rat is one animal that lives in Death Valley. During the day in Death Valley, it gets hotter than 100°F. The kangaroo rat rests all day in a hole in the ground. It covers the hole with grass to keep out the heat. The kangaroo rat comes out at night when it is cooler. This little rat is also very good at conserving (节约) water. It gets all the water it needs from the food it eats. Some kangaroo rats never take a drink of water in their whole lives!

    The sun makes the desert sand very hot. Animals, like snakes, get too hot if they lie on the hot sand too long. One snake, called the sidewinder, can solve this problem. When it travels, the sidewinder bends (使弯曲) its body into a“W”shape. Then it uses the bottom (底部的) parts of the“W”like legs and walks sideways (向一侧). That way it touches only a little of the sand at a time, so the hot sand doesn't burn the snake. This strange way of moving is how the sidewinder got its name.

    A lot of water in the desert is too salty for most animals to drink. All water has some salt in it. As the desert heat dries up pools of water, the salt is left behind. The remaining water in these pools can be much saltier than the ocean. One kind of fish, the desert pupfish, can live in these salty pools because it can drink the salt water.

    How do animals communicate (交流) with each other? They have special "languages". In fact, they are using signals (信号). Different signals have different meanings.

    For example, when a bee (蜜蜂) finds food somewhere, it flies home quickly. It can't speak, but it can tell others by dancing. Other bees will know where and how far the food is.

    Some animals show their feelings by making sounds. For example, when a dog is angry, it barks (吠). At this time, you'd better stay away from it. Birds can make several sounds to show different meanings. Sometimes we humans show feelings by making sounds instead of by speaking. For example, when we feel painful (疼痛的), we cry "Oh!" or“Ouch!".

    We humans have languages and words. We can communicate face to face by speaking. We can write down what happened in order to remember clearly. We can also send (寄) messages to people far away. But animals can't.