A hobby can be almost anything that a person likes to do in his free time. Hobbyists raise pets, watch birds, paint pictures, play the piano and grow flowers. They also go to concerts, climb mountains, go fishing, skate and swim. They collect everything from books to butterflies and from boxes to stamps.

    People follow hobbies because these activities offer enjoyment, friendship，knowledge and relaxation. Sometimes they even make money by following a hobby. Hobbies help people relax after hard work, and provide a balance between work and play. Hobbies also offer interesting activities for persons who are retired. Anyone, rich or poor, old or young, can follow an interesting hobby.

Hobbies can also help a patient to keep healthy. Doctors have found that hobbies are useful in helping patients (病人) recover from illness. Hobbies give patients who can't move around something to do, and provide interests that keep them from thinking about themselves. Many hospitals treat (治疗) patients by having them take up interesting hobbies. Anyone, old or young, sick or well, rich or poor, can follow a good hobby, in spite of his age, health or money.

    In early times, most people were too busy making a living to have many hobbies. But some persons who had spare time did enjoy hobbies. People today have more time than ever before for hobbies. Machines have now reduced much time that people must spend on their jobs. More people retire at an earlier age than before. Those who have developed hobbies never need to worry about what to do with their newly-found free time hours.

    Sir William Osler, a famous Canadian doctor expressed the value of hobbies by saying, “No man is really happy or safe without a hobby. ”

B

    For many people of Norway(挪威), skiing(滑雪) is the best way to have fun in winter. Almost everyone can ski. Children learn to ski after they learn to walk. Long, long ago in Norway, there were no buses, trains or cars. People had to find a way to walk over the deep snow. Skis were the right answer!

    Although they love winter, the people of Norway are also happy to see summer come. They enjoy the out-door activities at any time of the year. In summer they swim and sunbathe near the beach. Some people go hiking and go mountain climbing. Sail-boating is also very popular during the warm sunny summer months.

    The Norwegians(挪威人), like people everywhere, find many in-door ways to have a good time. During the long winter they also enjoy movies. They like to read books from the libraries in all seasons. Family life is very important to the people of Norway.

    In some science fiction movies, evil robots refuse to die, no matter how hard people fight back.

    Now science fiction has become science fact. For the first time, scientists have made a robot that can take a beating (挨打) and keep on going. Scientists from Cornell University made the robot, which looks like a spider with four legs.

    Until now, even the most advanced (先进的) robot was almost certain to break down when it was damaged. That is because its computer inside simply doesn't know how to make the machine work after its shape has changed.

    To deal with this problem, the scientists put eight motors (发动机) and two sensors (传感器) that read how the machine is working. They all give signals to the machine's software. Using this information, the computer can then figure out the machine's shape at any moment.

    The new technology is a big advance in robot-making, scientists say, and it's far from scary. It may someday help scientists create better artificial (假的) arms and legs and give new freedom to people who lose them. It might also help scientists understand how people and animals figure out their own sense of place in space.

    “It has been difficult to design robots that can work well when the environment changes or when it's damaged,” says Olaf Sporns of Indiana University in US. “With this work, we are nearer to solving this problem.”

    A study of sleep in sparrows suggests the relationship between sleep and the ability to learn may be more complicated (复杂) than realized．

    Niels C. Rattenborg of the University of Wisconsin—Madison wanted to find out how the sparrows were able to deal with getting so much less sleep．He and his team brought eight wild birds into a lab and watched them for one year．They invented a game to check how well the birds could learn．In the game, the sparrows had to peck (啄) three buttons (按钮) in a certain order to get a food treat．The scientists discovered that the birds' ability to learn the right button order depended on (依靠) two things, the time of year and the

amount of sleep the birds had．

    During the migration (迁徙) season, the sparrows were restless at night and got much less sleep than usual．Even so, they were able to understand how to get the food quickly as if they'd had a regular night of sleep．Outside the migration season, they found the sparrows that got less sleep than usual had much more difficulty learning how to get the food treats than birds that had a regular sleep．

    The results show that the sparrows can deal with much less sleep during the migration season than usual．If scientists can find out why, they may learn from sparrows and find ways of helping people deal with getting much less sleep．Until scientists fully understand the relationship between sleep and learning, it's better to get plenty of sleep when preparing for an exam．

    People have understood that kindness is good for the person who receives help. For example, when we give food to a hungry person, he is lucky. However, scientists have recently begun to study the effect(影响)of the kindness on the person giving it. What they have found is that doing good is good for the doer(行为者).Acts of kindness can improve health, help a person reach goals and even add years to a person's life.

    The first study to show the connection between doing good and living a long life was a study on aging(衰老). Beginning in 1956, scientists studied a group of married mothers for 30 years. They thought the women with the most children would die first. But the number of children a woman had did not matter. Wealth did not matter. Education did not matter. What did matter was whether they volunteered. Women that volunteered had fewer diseases during their life.

    Many other studies have found the same positive(积极的)effects. Helping other people improves long-term health. The gains are the same for men, women, old people and the young. Those who volunteered had fewer serious diseases than those who did not volunteer. This included diseases such as heart attack, cancer and stroke.

    Scientists are studying many possible causes. One possible cause is an increase in antibodies(抗体)，which help fight against disease. One study showed the body produces more antibodies after an act of kindness.

    Another one is an increase in Oxytocin(催生素)，it is a chemical that fights the effects of stress from life. Scientists have found a link between being kind to people and an increase in the chemical oxytocin.

    The world uses about a thousand million (百万) tons of water a day. Water is a human right and everyone should have their share. Yet more than 700 million people around the world have trouble getting clean, safe water.

    Treating wastewater is a good way to provide fresh water for us. And it also helps the environment by keeping waste out of rivers and oceans. 80% of wastewater around the world is not treated at all, and it is running into oceans. But now we have got the technology to treat and reuse the wastewater.

    While 75% of our planet is covered with water, only about 2% is fresh water—that comes from rivers, lakes, ice and snow. The rest, 98% of the water, is in seas and oceans. It is too salty to drink. Then desalination businesses come in. More than 19,000 factories have been built around the world, mostly in coastal countries. They process (加工) more than 92 million tons of water every day. But the technology they use requires a lot of energy.

    Scientists are working to create a less costly technology. They want to produce 20 times more clean water and make sure everyone has enough. But for now, the world still faces each day with not having enough water for everyone.