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.

Eating lots of vegetables is good for our health. Different vegetables can help our bodies in different ways. Eating carrots is good for our eyes. Carrots can help us see better at night. Do you want to have strong teeth? If so, you can eat some peas(豌豆). Peas have vitamin(维生素) K in them. Vitamin K is helpful to your teeth. Do you like tomatoes? They look nice. Doctors call tomatoes "healthy vegetables", because they can help you not to get cancer(癌症). They also have a kind of special vitamin PP. It can keep our skin(皮肤) healthy. So it is important to eat some tomatoes. Don't forget about spinach(菠菜). The spinach leaves have vitamin A, vitamin C and vitamin E. They help our bodies make red blood cells (血红蛋白).Vegetables are very important to us, but we can't only eat vegetables. We also need to eat other kinds of food to keep healthy.

    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.

Feet are an important part of you. Without them, you couldn't stand up, walk or run around. Your feet work so hard that sometimes they get sweaty (出汗).

Think of a hot summer day when you have been walking around all afternoon. Your feet have been in those trainers for a long time! The moment you take off your shoes, you feel good and relaxed, but your feet smell bad. You may think it is because of the sweat. But in fact, sweat itself has no smell. It's the bacteria (细菌) on your skin (皮肤) that mix with it and gives off a bad smell.

Bacteria love dark and wet places like the inside of sweaty shoes. The sweatier you get, the more bacteria there will be. When you wear your shoes, bacteria will have a good meal on your feet. They eat dead skin cells from your skin and then leave a kind of waste called organic acids (有机酸). These organic acids smell bad. Things will become better if you wear cotton socks.

What would you do if you see someone hurt badly? The following will help you to learn some important skills to give casualty (伤员) first aid.

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The first and most important thing you must do is to make sure the place is not dangerous. Can you see anything that might not be helpful to you? Can you hear anything that could be dangerous?

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When you see someone has been hurt, you may feel scared. If you feel yourself starting to be nervous, try to calm yourself down. For example, talk to people you trust about what happened, and you'll be relaxed.

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When someone needs first aid, talking to him will help him to stay calm and feel safe. Even if he does not answer you, you should still tell him what you are doing. It will let him know that you are helping him.

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Sometimes, the casualty will need more help than you are able to give. The best thing you can do is to phone some people for help. They can give you some useful advice or offer you some help.

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There are also many other things to do. Try your best to help the casualty. Asking people around you for help is really better than waiting for doctors. Besides, you can also try to keep in touch with his families and friends.

You know an apple is healthier than candy. But how do you make changes and eat really healthy food all the time? Start here with these wonderful rules.

You can finish all of the work in less than ten minutes.

Rule 1: Eat two pounds of vegetables. Remember to eat many vegetables every day. One pound is cooked and one pound is raw. They really help you to fight against some discases(疾病) and protect your health.

Rule 2: Put an egg on your meal. The egg is a kind of wonderful food. As long as you have eggs in your fridge, you can make a healthy meal with a fried egg, or add an egg to a bowl of rice.

Rule 3: Eat a little junk food. Junk food is delicious but it is not good for our health. But it's so cheap that you may like eating too often Eating it a little can be possible.

Rule 4: Eat some desserts(甜点) every day, but not too much. Not all desserts can make you fat. Some of them are delicious and healthy. A chocolate is a kind of dessert. And it's good for you to eat a little chocolate. Be smart enough to choose some desserts and try to improve your health.