Most cars run on gas. Gas cars work verywell. But there is a problem. Cars that run on gas make the air dirty. Thedirty air is not good for people, animals or trees. Gas cars make the air dirtyfor all living things. What can we do? We can drive electric cars!

    Electric cars do not use gas. These cars donot make the air dirty. These cars have batteries that power their motors (马达). The batteries can be charged (充电) manytimes. They can be used again and again. This makes electric cars great.

    But electric cars have problems too. Theyare slower than gas cars. They are also very quiet. This means that some peoplecan't hear them when they go by. They may not think a car is coming. So theyhave to be careful.

    People are finding ways to make electriccars better all the time. Maybe one day all cars will be electric. That wouldbe much better for the world.

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.

In China, very few children make pocket money(零花钱).1 , in western countries, most kids make pocket money by themselves. They make money in many different 2 .

When kids are very young, their parents help them sell the fruits of their own trees to neighbors. Kids may also help their 3 do housework to make money at home. When they 4 sixteen, they can make money by sending newspapers or by working in fast food restaurants, 5 during the summer holidays.

 There are many advantages (优点) of making pocket money by kids 6 . First of all, they 7 the value (价值) of money by working hard so that they will not waste any. Secondly, they learn to 8 money to buy things they need or want, such as books, pencils, movies and even clothes they like. Thirdly, they learn to 9 the daily life problems by helping their parents or others. Making pocket money is 10 for children when they grow up. That is why parents encourage their kids to make pocket money.

Sometimes when the rain falls hard and fast on you, it might hurt a little. But what happens when it hits a mosquito(蚊子)?

In 2012, David Hu, a scientist at Georgia Tech, became interested in this problem and decided to do a research. He used a high- speed camera so that he could watch the mosquitoes in very slow motion and find out what they' re doing when they' re out in the rain.

What he found is that when a raindrop falls on a mosquito, it's like when a bus hits a person. Besides, the little insect(昆虫) is hit by a raindrop about once every 20 seconds. So why don't we see many dead mosquitoes after it rains?

A mosquito is as big as a raindrop, but it is much lighter—0.002g only. This saves its life in raindrop hits. Because the mosquito is so light, when it is hit by a raindrop, it won't experience a force that is strong enough to kill it.

The study also found that when a mosquito is hit by a raindrop, the insect is pushed by the raindrop and falls together with it. But the mosquito doesn't get wet easily because it is covered with hairs which keep off water. After dropping about 6 cm, it will roll off the raindrop and fly away.

However, this trick isn't always successful. If the mosquito flies too low when it is hit by the raindrop, it won't have time to fly off. Then it will hit the ground and meet its death.

①A tidy desk helps you find things easily and is good for your study. But how can you keep your desk tidy?

②First, only put things you need on your desk. For old books, you can put them in the bookcase. Get a box for small things you don't need every day, and you can put your pens and pencils in a pencil box.

③Second, don't put food or drinks on your desk, because they can make your desk dirty. Go to the kitchen when you want to eat.

④Third, put important(重要的)things next to you. Then it is easy for you to get them.

⑤Fourth, clean your desk every day. If you do it every day, you can have a new day with a tidy room the next morning.

提示：

1. 很多人浪费水；

2. 有些人出门不关灯；

3. 人们每天制造很多垃圾；

4. 很多资源被浪费，资源短缺；

5. 呼吁人们不要浪费资源，回收利用废物。