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.

    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.

    We'resitting too much and it's dangerous. Most Americans spend more than seven hourssitting every day, and the more you sit, the weaker your body will be.Fortunately, there are simple changes you can make during the day—anywhere, even at the workplace—to improve your health.

    Park a fewblocks away from the office each morning and walk to work.

    Thisallows you to start off your mornings actively and be ready to take on thework. If you take the bus, get off one stop earlier to take some light exercisebefore 8 a.m.

    Get up andmove around the office once every 60~90 minutes.

    Whenyou're busy with work, it's easy to forget the time. Set the alarm to remindyou to get up and take a walk around the office. You can use this time to fillup your water bottle or go to the bathroom.

    Askquestions and discuss questions face to face.

    Go to yourco-workers' office to discuss questions face to face, rather than send an emailevery time you have a question. This gives you a good excuse to move.

    Use yourlunch break to move around outside.

    So manyAmericans today work during their lunch break. When possible, take advantage ofthis time to walk outside and enjoy the nice weather. Fresh air can make youkeep a clear mind.

    Maybe a lot of thin people will be worried about their health if the inside fat matters.

    Some doctors now think that the inside fat around important organs like the heart or liver could be as dangerous as the outside fat which can be noticed more easily.

    "Being thin doesn't surely mean you are not fat," said Dr Jimmy Bell at Imperial College. Since 1994, Bell and his team have tested nearly 800 people with MRI to create "fat maps" showing where people store fat.

    According to the result, people who keep their weight through the food they usually eat rather than exercise are likely to have major deposits (堆积物) of inside fat, even if they are thin.

   Even people with normal Body Mass Index (体重指数) scores can have surprising levels of fat deposits inside. Of the women, as many as 45 per cent of those with normal BMI scores (20 to 25) actually had too high levels of inside fat. Men were nearly 60 per cent.

    According to Bell, people who are fat on the inside are actually on the edge of being fat. They eat too many fatty and sugary foods, but they are not eating enough to be fat. Scientists believe we naturally store fat around the stomach first, but at some point, the body may start storing it elsewhere.

    Doctors are unsure about the exact dangers of inside fat, but some think it has something to do with heart disease and diabetes (糖尿病). They want to prove that inside fat does harm to the body's communication systems.

    The good news is that inside fat can be easily burned off through exercise or even by improving your eating habits. "If you want to be healthy, there is no other way. Exercise has to be an important part of your lifestyle," Bell said.

Better hygiene (卫生) habits can help you stay healthy

According to the World Health Organization, 60 percent of people's health problems are related(与…相关) to everyday hygiene habits. As the COVID-19 spreads across the world, governments and organizations in many countries have suggested that people should pay more attention to their daily hygiene practices.

In China, for example, people usually share dishes together at the dining table. But this habit has a high risk of spreading diseases through saliva(唾液). To fight against COVID-19, many cities in China, including Beijing, Shanghai and Guangzhou, have called on people to order separate(分开的)meals or use serving chopsticks(公筷) to take their food. Many people also suggest that Chinese should continue these habits after the outbreak.

In the US, the Centers for Disease Control and Prevention has asked people to develop healthy hygiene habits. For example, people should cover their mouth and nose with a tissue when they cough or sneeze.

    According to a survey by YouGov, a British market research company, many Americans have taken action to change their daily habits in the face of COVID-19.

Early to bed and early to rise makes a man healthy, wealthy (富有) and wise (聪明). This is an old English saying. It means that we should go to bed early at night and get up early in the morning. If we do, we shall be healthy. We shall also be rich and clever.

Is this true? Perhaps it is. The body must have enough sleep. Children of your age need ten hours' sleep every night. If you go to bed late, you can't have enough sleep. Then you can't think carefully and your homework will be wrong. You will not be wise and you may not become wealthy!

Some people go to bed late at night and get up late in the morning. This is not good for them. We should sleep at night when it is dark. The dark helps us sleep well. When the daylight comes, we should get up. This is the time for exercise. If the body is not used, it will become weak.

Exercise keeps it strong. Exercise helps the blood (血液) to move around inside the body. Blood takes nutrition (营养) to all parts of our bodies. The brains (大脑) in our heads also need blood. We think with our brains. If we keep our bodies healthy, and take exercise, we can think better!

Our bodies also need air to breathe (呼吸). Without air we will die. Get up early in the morning and we can have plenty of clean, fresh air. That will keep us healthy and happy.