25. Necessity is the mother of invention.
IV.下面是几则学生的作文，首先修改文中的语言错误，然后提出内容修改意见。
1. Adventure is very popular in the West Country， but there are few people love adventure in China. Many people think adventure is too dangerous， but I think adventure is a spirit of conquering the nature. Succeeded adventures need luck and spirit brave. If you are weak， I think you will never succeed. Just with the spirit adventure， many famous scientist invented many things. In our lives， we just poor in the spirit adventure， if we have spirit adventure， I think we will live happier.
2. There is a kind of people in the world. They doesn"t wanted quiet and comfortable life. They enjoy the adventure and unique experience. So， they always try to conquer all kinds of danger. This is a spirit of never satisfied with what he has achieved. One can"t make a progress if one is afraid of difficulties. Only adventure can defeat the difficulties. We are youth of over the century. We must dare to face the difficulties and defeat it. So， we must learn how to adventure.
3. Watching TV too much is bad for our eyes. We use the eyes to watch TV. If we watch TV too long， our eyes might tire. So it is bad for our eyes if we watch TV too much. If you want to watch TV more， you must spend more time for it. So you might have no time， or have not enough time for studying. Then you might fail in exam. So watch TV too much is disadvantageous.
4. My father is very strict with his children， especially me. He won"t let men out of the house unless I"ve done all my homework. Frankly， I don"t care whether I go to school or not. School is such a waste of time. There aren"t any good jobs， anyway. My mother doesn"t agree with my father. They quarrel a lot. Sometimes I wish they would get a divorce， but then who would I live with？
5. Watching TV has many advantages， but paying too much time on TV would have many disadvantages. Watching TV can help us receive many important information. For example， watch TV news， and it may improve our study. But if you pay too much time on TV set， it occupies most of your time， then， your time for study is not adequate， and this would influence your study. I propose that first we should have adequate time for study and then we can watch TV， this would bring us more advantages.
V. Read the following paragraphs and find out what details the authors use to support their topic sentences．
1. Warm water freezes more quickly than cold． Sir Francis Bacon stated that almost four hundred years ago． But few people believed him-till 1970． In that year， Canadian scientist George Kell proved the English scholar right． Dr． Kell filled an open pail with cold water． He filled another with warm water． He exposed both to the same low temperature． The warm water froze first．
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2. There is a relationship between your blood type and your nationality. Among Europeans and people of European ancestry， about 42 percent have type A while 45 percent have type O. The rarest is type B．Other races have different percentages．For example，some American Indian groups have nearly 100 percent type O．
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3. Although thousands of people have been killed by sudden eruptions，volcanoes also benefit man，Tin，tungsten， gold and other metals have been brought closer to the earth"s surface. Chemicals in the ash have enriched farmland．When solid，lava is agood building material. And in Italy，steam from active volcanoes supplies heat and power to surrounding areas．
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