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.

    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.

    We're sitting too much and it's dangerous. Most Americans spend more than seven hours sitting 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 few blocks away from the office each morning and walk to work.

    This allows you to start off your mornings actively and be ready to take on the work. If you take the bus, get off one stop earlier to take some light exercise before 8 a.m.

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

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

    Ask questions and discuss questions face to face.

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

    Use your lunch break to move around outside.

    So many Americans today work during their lunch break. When possible, take advantage of this time to walk outside and enjoy the nice weather. Fresh air can make you keep a clear mind.

Feb. 17 should have been the start of the spring semester for many middle and primary schools in China. However, to control the spread of the COVID-19, many schools had delayed the start of the semester, following instructions from the Ministry of Education (MOE). But students in China were still studying.

Instead of having classes at school, many students in Beijing and Guangzhou began their first day of online classes on Feb 17. Students in Shanghai started online classes on March 2. "In the morning, I have English class, followed by Chinese and math, " Liu Bo, a Junior 3 student from Beijing, told Xinhua. "I have also learned about epidemic(流行病) prevention. "

According to the MOE, students were mainly taking classes to review previous knowledge rather than taking new classes during the online study period. Online courses were required to include contents about epidemic prevention, psychological health (心理健康) and educational activities (教育活动).

"Online courses are only temporary measures (暂时的措施) taken during the epidemic, so when the new semester begins, schools should not replace(替代) classroom teaching with online classes, " Lu Yugang from the ministry told China Daily.

The ministry also called on schools not to increase their students' schoolwork burden(负担). Schools should not ask students to study online for long periods of time or study things beyond( 超出) their curriculum(课程). Students must have enough time to rest, the ministry added. Also, it stressed that protecting students' eyesight must be a priority(优先).

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.

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.