Most people around the world are right-handed. This also seems to be true in history. In 1799, scientists studied works of art made at different times from 1,500 B.C. to the 1950s. Most of the people shown in these works are right-handed, so the scientists guessed that right-handedness has always been common through history. Today, only about 10% to 15% of the world’s population is left-handed.

 Why are there more right-handed people than left-handed ones? Scientists now know that a person’s two hands each have their own jobs. For most people, the left hand is used to find things or hold things. The right hand is used to work with things. This is because of the different work of the two sides of the brain. The right side of the brain, which makes a person’s hands and eyes work together, controls the left hand. The left-side of the brain, which controls the right hand, is the centre for thinking and doing problems. These findings show that more artists should be left-handed, and studies have found that left-handedness is twice as common among artists as among people in other jobs.

 No one really knows what makes a person become left-handed instead of right-handed. Scientists have found that almost 40% of the people become left-handed because their main brain is damaged when they are born. However, this doesn’t happen to everyone, so scientists guess there must be another reason why people become left-handed. One idea is that people usually get right-handed from their parents. If a person does not receive the gene (基因) for right-handedness, he/she may become either right-handed or left-handed according to the chance and the people they work or live with.

 Though right-handedness is more common than left-handedness, people no longer think left-handed people are strange or unusual. A long time ago, left-handed children were made to use their right hands like other children, but today they don’t have to.

 We have known for a long time that flowers of different plants open and close at different time of day. Yet no one really understands why flowers open and close like this at particular times. It is not as simple as we might think, as new experiments have shown. In one experiment, flowers were kept in darkness. We might expect that the flowers, without any information about the time of the day, did not open as they usually do. In fact, they continued to open at their usual time. This shows that they have some mysterious (神秘的) way of knowing the time.

    Their sense of time does not depend on information from the outside world; it is, so to speak, inside them, a kind of “inner clock”. This discovery may not seem to be very important. However, it was later found that not just plants but also animals including man have this “inner clock” which controls working of their bodies and their activities.

Human beings, then, are also controlled by this mysterious power. Whether we wish it or not, it affects such things in our life as our need for sleep, our need for food. And our ability to concentrate(集中).

What will the weather be like? Some people say they can know what the weather will be like from birds. They kook at birds. When they see birds fly high out to the sea, they say it will be a nice day. For birds donˈt like to fly out when it could rain. When the weather will be bad, sea birds turn back and stay on shore.

A big wind may come with a rain. Birds do not like to fly in a big wind. They may sit in a tree when rain is on the way.

Some people look at different animals on a farm. Other animals can alsotellthe weather. A chicken may make a big noise when rain is on the way. It may run here and there. A frog can show the weather, too. A frog will make a big noise when rain is on the way. It will stay in the water. On a nice day, it will come out up high out of the water.

“Life is speeding up. Everyone is getting unwell.”

This may sound like something someone would say today. But in fact, an unknown person who lived in Rome in AD（公元） 53 wrote it.

We all love new inventions. They are exciting, amazing and can even change our lives. But have all these developments really improved the quality of our lives?

Picture this. You’re rushing to finish your homework on the computer. Your mobile phone rings, a QQ message from your friend appears on the screen, the noise from the television is getting louder and louder. Suddenly the computer goes blank and you lose all your work. Now you have to stay up all night to get it done. How happy do you feel?

Inventions have speeded up our lives so much that they often leave up feeling stressed and tired. Why do you think people who live far away from noisy cities, who have no telephones, no cars, not even any electricity often seem to be happier? Perhaps because they live simpler lives.

One family in the UK went “back in time” to see what life was like without all the inventions we have today. The grandparents, with their daughter, and grandsons Benjamin, 10 and Thomas, 7, spent nine weeks in a 1940s house. They had no washing machine, microwave（微波炉）, computer or mobile phones.

The grandmother, Lyn, said, “The more things you have, the more difficult life becomes.” The boys said they fought less. Probably, they said, because there was less to fight over, such as their computer. Benjamin also noticed that his grandmother had changed from being a “trendy（赶时髦的）, beer-drinking granny”, to one who cooked things.

根据短文内容，选择正确答案。

A kind of little cars may take the place of (取代)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.

根据短文内容，选择正确答案。

Many people think that the hump* of the camel is full of water. They think this is the reason that camels do not have to drink very often in the desert*, but they are not right. A camel’s hump is not full of water. It is fat*. The camel’s body can use the fat later when it is hungry, but it does not help the camel go for a long time without* drinking. A camel can do this because it does not sweat* very much.

When people and most other animals get hot, they sweat. Sweat is mostly water from the body. So when people sweat, they lose water and soon have to drink. If they don’t drink water, they die. When a camel gets hot, it does not sweat very much, so it does not lose much of the water in its body. It does not need to drink very often.

LONDON—Scientists have found an unusual way to prevent our planet from overheating: move it to a cooler spot. All you have to do is to send a few comets (彗星) in the direction of Earth, and its orbit (轨道)wil l be changed. Our world will then be sent moving into a safer older part of the solar system.

This idea for improving our climate comes from a group of US NASA (美国航空航天局) engineers and American astronomers. They say their plan could add another six billion years to the useful lifetime of our planet—hopefully doubling its working life.

The plan put forward by Dr. Laughlin, and his colleagues Don Korycansky and Fred Adams, needs carefully directing a comet or asteroid (小行星) so that it passes close by our planet and sends some of its gravitational energy (重力势能) to Earth.

“Earth’s orbital speed would increase as a result and we would move to a higher orbit away from the sun,” Laughlin said.

Engineers would then direct their comet so that it passed close to Jupi ter(木星) or Saturn (土星). The comet would pick up energy from one of these giant planets. Later its orbit would bring it back to Earth, and the process would be repeated.

In the short term, the plan provides an ideal way to worldwide warming, although the team was actually worried about a much greater danger. The sun is certain to heat up in about a billion years and so “seriouslycompromise” our biosphere (生物圈)—by cooking us.

That’s why the group decided to try to save Earth.

The plan has one or two worrying sides, however. For a start, space engineers would have to be very careful about how they directed their asteroid or comet towards Earth. The smallest miscalculation (误算)in orbit could fire it straight at Earth—with deadly results.

There is also the question of the moon. As the present issue of Scientific American magazine points out, if Earth was pushed out of its present location, it is “most likely the moon would be stripped(剥离)away from Earth,” it states. This would greatly change our planet’s climate.

  We have heard about people who have special memories. Recently there has been a report about a woman from Australia who can remember almost every detail (细节) of all the events in her daily life.

    Rebecca Sharrock, 25, is one of just 80 people worldwide who have been identified(确定) as having Highly Superior Autobiographical Memory ( HSAM,超级自传体记忆症). It means she can remember every small event-which most people would forget with in (在......以内) days-as if it had happened just minutes ago.

    "I remember my mum putting me in the driver's seat of a car and taking a picture of me when I was 12 days old,” she said. " That's my earliest memory. I remember every day since then. I can't tell all the dates exactly because I was too young to understand calendars, but I remember what I did that very day, what the weather was like and so on.”

     Rebecca can also re-experience taste. If she's eating something that she doesn't like, she thinks about Black Forest cake, her favorite food, and the memory will be so strong that she can nearly "taste” it.

     However, sometimes her memories prove (证明) to be painful. Because they're not just events that she remembers. "When I relive（再体验) memories, the feelings return, too,” Rebecca said. "For example, I remember falling over when I was three at my grandparents' house and hurting my left knee. Talking about it now, I feel painful in my left knee. "

     "At night, I have to sleep with the radio/recorder and a soft light on,n she added. "1f it's too dark or quiet, my mind would be filled with all these memories and I can't sleep. "

More and more people like bicycling and it is no surprise. It is fun, healthy and good for the environment（环境）. Maybe that’s why there are 1.4 billion bicycles and only 400 million cars on roads worldwide today. Bikes can take you almost anywhere, and there is no oil cost!

Get on a bicycle and ride around your neighborhood. You may discover something new all around you. Stopping and getting off a bike is easier than stopping and getting out of your car. You can bike to work and benefit（受益）from the enjoyable exercise without polluting the environment. You don't even have to ride all the way.

Folding（可折叠的）bikes work well for people who ride the train. Just fold the bike and take it with you. You can do the same on an airplane. A folding bike can be packed in a suitcase. You can also take a common bike with you when you fly. But be sure to look for information by getting on airline websites. Not all airlines are bicycle-friendly to travelers.

Health Benefits of Bicycling:

It helps to prevent heart diseases.

Bicycling helps to control（控制） your weight.

A 15-minute bike ride to and from work three times a week burns off five kilos of fat in a year.

Bicycling can improve your mood（心情）.

Exercise like bicycling has been shown to make people feel better, more relaxed and self-confident.

Bicycling is healthier than driving.

A workmate of mine lives in the same street as me. He drives about 5 kilometers to work every day while I cycle the same distance almost every day. I must say that I ocassionally(偶尔)take the car if the weather is bad, or I ‘m very tired or in a hurry. Imagine my surprise when I cycled to work one day, went for a shower in the sports center and saw my neighbour in the gym on the cycling machine after driving to work! I share an office with another workmate who lives near to me, she drives to work every day, and the end of the day, she drives to a gym. I don’t see the logic(逻辑). It would be much easier to cycle to work so that you have some exercise every day as part of your daily routine.

  I try to advise them to cycle to work, so I did some research about the benefits of cycling to work. Of course, cycling has some advantages over driving. It’s cheaper and it’s better for the environment, and you don’t have to find a parking space. The point about parking space is an important one as the car parks are often full. I know that my workmate sometimes spends 15 minutes looking for a parking space! It’s true that cycling is a little slower than going by car, but at rush hour it doesn’t make much difference. The time it takes to cycle is generally easier to predict than the time it takes to drive. When there is heavy traffic, people on cycles can get past, while people on cars have to wait.

  There are clear health benefits to cycling. According to one expert, if you cycle regularly you should be as fit as a younger person. I ‘m 47 and I still play football in a team, so I would say that his opinion is true. As well as being good for your health, cycling can reduce your stress. I also find that when I can’t solve a problem at work, the answer often comes to me when I’m cycling. Sometimes the harder you think about a problem, the harder it is to find the solution. And you really need to pay less attention to the problems. Cycling relxes the mind.

  I am going to say to my workmates—“two wheels good, four wheels bad” every day until they get on their bikes!