The best-known (最熟知的) vegetable in the world is the potato. It grows in many places and does not need rich soil(土壤) like many other crops. But until four hundred years ago, the Europeans(欧洲人) began to know the potato. But today it's one of the main foods in Europe(欧洲). About half of the world's potatoes are grown in Europe.

    In France the potato was not grown for a long time .Here is story about Louis. In 1778 he saw some potato flowers for the first time .He liked them so much that he picked one and put it in his buttonhole. He was interested in the flowers not the potatoes themselves.

      Astronauts are not like pilots, who fly into sky. They need some special trainings. They will fly into space. First they go to the Johnson space center in Houston Texas. They are tested there. Space doctors want to know how strong and smart they are.

      First of all, their hearts are tested. The people walk or run. Next, the space doctors see how fast their hearts are beating.

      Then it is another important test. In this test the person must curl his body up in a ball. And when he is in that position, he will be put into a round cloth bag. The doctors don't tell him how long he will have to stay in the bag. If a spaceship broke down in space, the astronauts would get into bags like these. Then they would have to wait, curled up in darkness, until they are saved. You can know that an astronaut must not be afraid of tight spaces or darkness.

      After these tests, scientists only choose the best people to start astronaut training in a training center. They will learn many other things in training. They will learn how to jump out of moving airplane, to blow up a lifeboat and get into it while they are in the ocean.

They also have to learn how to get lifted out of the ocean by a helicopter.

      When they finish training, the astronauts go on to work. They stay in good situation by running and doing exercise. They read about the special jobs. In that way they will be able to learn new facts about space travel.

      Finally, the astronaut is told to go to work on a flight into space. The members begin to know each other first. Then they can learn which jobs each will do.

    There will be a kind of new cars in the future. People will like this kind of small cars better than the big ones. The car is as small as a bike. But it can carry two people in it. Everybody can drive it easily, just like riding a bike. Even children and old people can drive them to schools or parks.

    If everyone drives such cars in the future, there will be less pollution in the air. There will be more space for all the cars in cities, and there will also be more space for people to walk in the streets.

    The little cars of the future will cost less money to buy and to drive. These little cars can go only 65 kilometers an hour, so driving will be safer. The cars of the future will be fine for going around the city, but they will not be useful for a long trip.

    This kind of cars can save a lot of gas. They will go 450 kilometers, then they have to stop for more gas. They are nice cars, aren't they?

    Inventions usually make a big difference to people's lives. Do you have any great inventions at home? Do they help you a lot in your life or bring you much fun? Here are some of the most useful inventions in families according to a survey.

    Everybody hates rats. But rats may soon be man's new good friends. What happens after an earthquake? We send in rescue dogs. Why? Because they can smell people. Dogs save lives. They help rescuers to find living people. But dogs are big and they can't get into small spaces. So now a new research project is using a smaller animal to save lives: the rat.

    How does it work? First, the rat is trained to smell people. When this happens, the rat's brain gives a signal. This is sent to a small radio on its back, and then the rescuers follow the radio signals. When the rat's brain activity jumps, the rescuers know that someone is alive. The rat has smelled that person.

    Although there are already robots which can do this job, rats are better. Robots' noses don't work well when there are other smells around. Rats are good at that. Rats can also see in the dark, they are cheaper and quicker to train than dogs, and unlike robots, they don't need electricity!

    The "rat project" is not finished. But a scientist says, "It would be great. A rat could get into any place we couldn't get to, and a rat would get out if it wasn't safe." Perhaps for the first time in history, people will be happy to see a rat in a building (but only after an earthquake, of course).