Air pollution(污染) is a big problem. It's bad for all 1 things on Earth，and it is not the only one kind of 2.Water pollution makes fishand pollutes our drinking water. Noise pollution makes us get3more easily.

Many countries are making rules(规定) to fight against pollution. They try to stop people 4 burning coal(煤)in the city and releasing(排放) dirty smoke into the5.And if people use 6fewer cars，the air will get 7.

    8earth is our home. We must protect it and not destroy it. That is to say, we should keep the land, water and air 9.At the same time, we had better plant more trees10they can provide a lot of things for us and make our earth beautiful.

    Water is very important in our life. We drink it every day and1it to cook and wash things. We cannot live2water. But how can we save water?

    There are several ways to save water. Firstly， take shorter showers and don't leave the tap3when we don't need to use water.4 ， try to reuse water. It's the most important way for us to save water. At last， we should not5water so that we will have6water for years and years.

    To protect water is to7our life. Some people think there's much water8the Earth. In fact， there is only9water for us to use now. If we don't save it， it will surely be used out some day.

    So we should save water in order to save10. Do you think so?

    Do you often drink bottled drinks? Of course 1  is so cool to get a cold one right out of the fridge, right? But all those plastic bottles use a lot of oil and  2 the environment. Americans buy 3 bottled water than any other nation in the world. In order to make all these bottles, 17 million barrels (桶) of oil  4up. That's enough oil to keep a million cars going for twelve months.

    Many people choose 5 the bottles away after having the bottled drinks. In fact, instead of going out with the trash, plastic bottles can be turned into carpeting for clothing. Remember this: Recycling one plastic bottle  6save enough energy to power a 60-watt light bulb for six hours.7 , for every six water bottles we use, only one is recycled. The rest are sent as garbage (垃圾). Or, even worse, they end up 8  trash on the land or in rivers and oceans.

    So why don't more people drink water from the kitchen? Some people drink bottled water 9 they think it is better for them, but that's not true. The chemicals in the bottles themselves may get into the water which can do harm to people.

    So next time when you have drinks or water, please  10 to use a glass at home or carry water in a steel bottle. And if you want to do something more, try to collect plastic bottles and send them for recycling.

    At the beginning of this century, medical scientists made a interesting discovery(发现). We are bulk not just of flesh (肉)and blood but also of time. They were1to show that we all have a body clock inside us, which controls the2and fall of our body energies. It can 3us different from one day to the next.

    The idea of a body clock should not be too4because the lives of most living things are controlled by the 24-hour-night-and-day cycle. We feel 5 and fall asleep at night and become 6 and energetic during the day. Most people will have a bad feeling 24-hour cycle is 7. For example, people who are not used to working at night can find that luck  (缺少)of sleep causes them to 8 badly at work.

    Besides (除了) the daily cycle of sleeping and waking, we 9 have other cycle which lasts longer than one day. Most of us would 10 that we feel good on some days and not so good on others. Sometimes our ideas seem to be so active, and at other times they are not.