Haiyan is 7 years old. Her parents gave her an iPad as a gift for her birthday. A month later，her eyesight（视力）dropped to 300 degrees. This is serious for such a young child.

    Many children in China are facing the same problem: iPad using is bringing problems to their eyesight. The problem is so common that newspapers even call the iPad the "No. 1 killer of children's eyesight!"

    "There are about 30 shortsighted children coming every day, "said Hu Dali, an eye doctor at Guiyang Aier Eye Hospital. "Half of those children have poor eyesight because they have played with phones and iPads for too long. "

    Doctors and scientists say children's vision（视觉）is not yet fully developed and their eyes get tired more easily. The screen of an iPad uses very bright（明亮的）LED backlight. If children look at an iPad screen for a long time, their eyes do not have time to rest. This will make their eyesight worse over time.

    Doctors advise that users should hold their iPads between 40-60 centimeters（厘米）away from them. The brightness of the screen should be comfortable for children. Parents should also stop their children from using an iPad for more than one hour every day.

    Did you spend much time lying on the comfortable sofa at home during the summer vacation? How often did you do sports this summer? People across the world need to get moving, according to a new study by the World Health Organization (世界卫生组织).

    5% of adults do not get enough exercise, according to the study. This number hasn't changed from 2001. Because of this, about 1.4 billion people are close to deadly diseases (疾病) such as heart disease and cancer (癌症).

    People should do at least 2 and a half hours of "moderate intensity (中等强度)" exercise each week, such as dancing or swimming. They can also do 75 minutes of "vigorous intensity (高强度)" exercise, such as running or playing soccer, according to the WHO.

    As for how to exercise more, experts says that we don't have to go to the gym (健身房) every time For example, we can go up and down stairs (楼梯) a lot instead of taking the lift. If we can't go to a dancing class each week, standing on one leg for 30 seconds a day is very good too.

    The study also found that women are less active than men, 32% of women hardly ever take exercise, compared to (比较) 23% of men. Women spend more time at home taking care of children and doing housework.

    But unlike that in most other countries, men are less active than women in China, with 16.6% of men and 12% of women not getting enough exercise.

It is easy for many people to catch a cold in the springtime or fall. It makes us wonder if scientists can send a man to the moon, why can't they find a cure for the common cold? The answer is easy. There are actually different cold viruses out there. You never know which one you will get, so there isn't a cure for each one.

When a virus attacks your body, your body works hard to get rid of it Blood rushes to your nose and causes a block in it. You feel terrible because you can't breathe well, but your body is actually eating the virus. Your temperature goes up and you get a fever, but the heat of your body is killing the virus. You also have a runny nose to stop the virus from getting into your cells. You may feel very uncomfortable, but actually your wonderful body is doing everything it can to kill the cold.

Different people do different things to deal with colds. In the United States and some other countries, for example, people might have chicken soup to help them get over the cold. Some people take hot baths. Other people take medicine to stop different symptoms(症状)of colds.

There is one interesting thing to note一some scientists say taking medicine when you have a cold is actually bad for you. The virus stays in you longer because your body doesn't have a way to fight it and kill it Bodies can do an amazing job on their own. There is a joke, however, on taking medicine when you have a cold. It goes like this:

It takes about one week to get over a cold if you don't take medicine, but it takes only seven days to get over a cold if you take medicine.

    Water is the1of all the things we eat and drink. Not many people understand this but2quite true. The human body3go without food for a long time. We've got many examples for this. Yet two4three days without water can usually make people5. Man can't live6water.

    Many people don't understand how7water the human body needs8work well, and many people, especially young people, do not drink enough,9in very hot weather. Our body is mostly water, about 65% to 75%. That is to say about two thirds of our body is water. When we do sports, some of the water will get away from our body.10we don't drink some water, we won't have enough water. If we don't have enough water, we'll feel tired and many of us will get ill. So you know how important water is to us.

The weather is getting hotter and hotter. You are thirsty playing basketball or riding home from school. A cold drink may be just the thing. But be careful what you are drinking. Something that looks cool may not be good for your health.

There are plenty of "energy drinks" advertisement on TV. Most of them have beautiful colors and cool names. They tell you they are helpful to your health. Sounds great and lots of people believe them!

But after a careful check you may find that most energy drinks have lots of caffeine (咖啡因) in them. These drinks are especially aimed at young people, students, busy people and sports players. Makers sometimes say their drinks make you better at sports and can keep you awake. But he careful not to drink too much.

Caffeine makes your heart beat fast. Because of this, the International Olympic Committee has limited (限制) its use. Caffeine in most energy drinks is as strong as that in a cup of coffee or tea. Possible health dangers have something to do with energy drinks. Just one box of energy drink can make you nervous, have difficulty sleeping and can even cause heart problems. Scientists say that teenagers should be discouraged from taking drinks with a lot of caffeine in them.