阅读理解。根据短文内容，判断下列句子的正误。

        When we feel the ground moves suddenly, it means that an earthquake may come. Many of the earthquakes first come under the sea and then happen anywhere on the earth. Especially they often happen near the mountains and seas such as Wenchuan, Japan and Indonesia.

        When an earthquake happens, it's very easy to cause a tsunami (海啸). Houses fall down, many people are injured and even died.

        Now scientists are trying their best to study earthquakes. They make maps to show the “earthquake belts (地震带)”. So the houses there must be quite strong.

        We believe that scientists will be able to tell us when and where an earthquake will happen in the near future. Also, they can tell us what to do and how to do. People can even use earthquakes to do something for us humans.

    As space science develops, man has learned more and more about space. Space is not only amazing but also dangerous. While working in space, spacemen are facing danger as well as success.

    Scientists have found out that the radiation(辐射) is the greatest danger to spacemen in space. When spacemen are working in space, they are in danger of the radiation from the sun and other stars, which is bad for their health. The harm of the radiation won't be found until their children even grandchildren are born. Some special medicine may work a little, but no really effective medicine has been found so far. Space rubbish is also thought to be a great danger to spacemen. It's reported that there were 9,000 man-made things flying in space. About 30% of these are satellites, 10% are spaceships, and the rest are space rubbish. An explosion(爆炸) in space in 1999 made a cloud of 300,000fragments, each at least 4mm in size. A small piece of these even knocked a spaceship window and caused some damage(损坏).

    Scientists are watching and reporting any possible danger all the time. They are working to deal with space rubbish. Although space is really dangerous, it interests many people on the earth. In the near future, it may become possible for people to spend a few days in a space hotel. People may even choose to leave the earth and live in space in a few years. So scientists are doing everything they can to help improve the space environment.

①Eating good food and getting proper exercise are important to stay healthy. Getting enough sleep is important, too. Experts say that teenagers between the ages of 15 and 20 need 8 to 10 hours of sleep each night. 

②Your body needs to take a rest from all the activities it has done during the day. Your brain needs a rest, too. You are likely to get sick easier without enough sleep. 

③You have a "24-hour clock" inside your body that tells you when to be awake and when to go to sleep.  ▲  Blue light that comes from the Sun tells your brain to keep you awake during the day. When there is no blue light at night, the brain tells the body that it's time for sleep. 

④There are many things that stop the brain from telling your body when it's time to sleep. One of these is blue light at night. Today, people spend a lot of time watching television or looking at screens on computers or smart phones. These devices (装置) give off blue light. If you look at them at night, the blue light can trick your body into thinking it's daytime. Then it is more difficult to go to sleep.

⑤What should you do to get good sleep? Experts say that you shouldn't look at screens that give off blue light for at least one hour before going to sleep. 

⑥ Do not watch TV or use anything with a computer screen in bed. If you need to do something to fall asleep, it is better to read a book. Also, keep your bedroom as dark as you can. This will help you sleep well. 

Summer is coming and the weather is very hot. Many children want to go swimming. It's fun but dangerous at the same time. What do you need to do? Here are some good ideas.

Learn to swim first. Children over 5 years old need to take swimming lessons. You can learn some useful skills(必备技能) from the swimming lessons. These skills can save your life when you are in danger.

Keep away from some places with danger. Many children like going swimming in the rivers or the sea. But some of these places are very dangerous and aren't suitable for swimming. So don't swim in these places.

Make sure there is at least (至少) a partner around you. You can swim with your parents or your friends. And you should make sure that the partner is good at swimming and can keep you safe (安全的).

Always wear life jackets. When you are in the water or whenever you are near the water, don't forget to wear life jackets.