Hands play an important part in our daily life. But do you know which of your two hands you use more? Very few people use both hands equally well. Most of us are right-handed. Only about five people out of a hundred are left-handed. New-born babies can take hold of things with either of their hands, but in about two years they usually use their right hands. Scientists don't know why this happens.

Monkeys are our close relatives in the animal world. Scientists have found that monkeys like to use one of their hands more than the other, but it can be either hand. There are as many right-handed monkeys as left-handed ones. Next time you visit a zoo, watch the monkeys carefully, you will see that some of them will use their right hands and others will use their left hands. But most of the people use their right hands better and this makes life difficult for those left-handed people. We live in a right-handed world.

    Can you imagine astronauts' everyday life in space? They also need to eat,  1 , exercise and relax. They do the same things as us, but they do2 differently.

    On Earth, we put food on a plate and water in a glass. Gravity(重力) holds the food down and keeps the water in the glass.  3 there is almost no gravity in space, so food can float(漂浮) away, and astronauts must eat and drink4  .

    Sleeping is very different in space. Some astronauts like to float in the air, but most like to be in a 5bag. They tie the bag to a wall 6 they won't float away at night. Exercise is very important in space. On Earth, your legs 7 your body, but in space, astronauts float. So they do not use their legs often. This is very  8their legs, so they must exercise for thirty minutes every day.

    After a day's work, astronauts relax. They may listen to music, read, watch films, play games, or talk to their friends and families  9  the radio. Sometimes they just enjoy 10 in the air.

    When US student Olivia Priedeman, 17, woke up one morning, she thought she had had a dream about making plans with a friend.

    But it wasn't a dream. Her phone showed that during the night, Priedeman had read a text message from her friend. She did it while she was fast asleep.

    Reading and sending text messages while asleep called─ "sleep texting"─ is an unusual sleep behaviour, similar to sleep walking. It's also a growing problem among doctors: young people can't live without their cell phones.

    One in three teenagers sends more than 100 text messages a day, according to the Pew Internet & American Life Project. And at least four out of five teenagers said they sleep with their phone on or near their bed.

    Elizabeth Dowdell, a professor at Villanova University in Pennsylvania, has studied sleep texting. She said that having a phone nearby all night is a big part of the problem.

    Andrew Stiehm, a sleep medicine researcher with Allina Health in Minnesota, agrees. It's possible for the part of the brain that controls skills to wake up, while the part of the brain that controls memory and judgment(判断) may be still asleep. That's why some people can perform basic movements-such as walking, talking, texting or even driving while they're sleeping. Some of Dowdell's students said that they're disturbed by their nighttime texting behaviour. But because sleep texting is unconscious, it's a difficult habit to break. Dowdell said she knows of some students who wear socks on their hands to keep themselves from texting.

    Marjorie Hogan, a doctor at Hennepin County Medical Centre in Minneapolis, Minnesota, suggests keeping all electronic products outside the bedroom.

    National Eye Care Day on June 6th is a good chance for us to improve our eye health. What are common eye problems we have today? How can we protect our eyes? Read on to find out the answer.

    Eyes are important in our everyday life. We use them to read books, see colors and view the wonders of the world. But sometimes, we use them too much and it hurts them.

    In the past , nearsightedness（近视）was a common eye problem among children . This is mostly because of their bad eye habits, such as watching TV too long and reading books in bed .

    However , today's technology is changing the way we live . Children spend more time working and playing in front of computers , smart phones and iPads . US children spend more than 42 hours a week in front of electronic screens（电子屏幕）, US'ABC news reported .

    This has caused a new problem for our eyes : digital（数字的）eyestrain（眼疲劳）. People with digital eyestrain may get headaches , dry and red eyes , eye pain , watering and other eye problems .But don't worry . The following tips can help you protect your eyes . Try them out .

Screen advice :

⒈ When you are watching electronic screens , keep them at least 30 cm from your eyes . Try not to use your smart phone in direct sunlight .

⒉ Blink（眨眼）more often when you are looking at the screen . This can help to stop dry eyes .

⒊ Remember to take a 20-20-20 break : every 20 minutes , take a 20second break and look at something 20 feet ( about 6 meters ) away .

⒋ Spend less time in front of screens . One to two hours a day is OK for your eyes .

    Today, I am going to talk about life in the future. 1 will life be like in the future? No one can answer this question. Today, 2 in space can take photos of places billions of light years (光年) 3 the Earth. Science is developing very fast and people know more about space. 4 the help of science, we may also visit those places. We may have to 5 the Earth to live in space because the Earth will not hold so many people 6.

    In the future, we will travel very fast by 7. Our spaceship will be 8 a city, and every ship will carry 9 10, 000 people. There are also many buildings in our ships 10 hospitals, schools, shops and cinemas.

    Obesity (肥胖症) is becoming a problem in our busy society, almost one in three American adults is now considered to be obese. Children obesity is also at an all-time high.

    Obesity means being very overweight. If you are obese, you have too much body-fat. If you eat more food than your body can use, this will make you put on weight. Food that your body does not need will be stored (储存) as fat by your body.

    The following are the major factors (因素) that increase the risk of obesity.

    What you eat plays a major role in weight gain. Eating a lot of fattening food such as hamburgers, sweet drinks, ice creams and other sweet food can increase the risk of becoming obese.

    If you do not do enough exercise, you will put on weight as the food you eat is not being used to make energy for physical activities.

    The chances of your being obese are greater if your parents are obese.

    There are many psychological (心理的) factors that cause people to eat too much. People who are worried, unhappy or bored will often eat to make themselves feel better. This is known as comfort eating.

    Age is another factor, as you tend (趋于) to be less active when you get older. When you get older, you need to eat less, and if you do not eat less, you will put on weight.

    Obesity can cause many health problems such as heart problems, high blood pressure and many other serious medical conditions.