The world is not only hungry, but it is also thirsty for water. This may seem strange to you, since nearly 70 percent of the ear

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问题     The world is not only hungry, but it is also thirsty for water. This may seem strange to you, since nearly 70 percent of the earth’s surface is covered with water. But about 97 percent of this huge amount is sea water , or salt water. Man can only drink and use the other 3 percent fresh water from rivers, lakes, underground , and other sources. However we cannot even use all of that, because some of them are in the form of icebergs and glaciers(冰川). Even worse, some have been polluted.
    However, as things stand today, this small amount of fresh water is still enough for us. But our need for water is increasing rapidly almost day by day. Only if we take steps to deal with this problem now can we a-void a severe worldwide water shortage later on.
    We all have to learn how to stop wasting our valuable water. One of the first steps is to develop ways of reusing it.
    Today in most large cities, water is used only once and then sent out into a sewer system. From there it returns to the sea or runs into underground storage tanks. But it is possible to pipe used water to a purification(净化)plant. There it can be treated with chemicals so that it can be used again, just as if it were fresh from a spring.
    But even if every large city purified and reused its water, we still would not have enough. All we’d have to do is to make use of the vast reserves of sea water in the world and is to remove the salt. If we take these steps we’ll be in no danger of drying up.
The world is thirsty for water because we can only use______percent of the water covering the surface of the earth.

选项 A、3
B、more than 3
C、less than 3
D、97

答案C

解析 推理判断题。由文章第一段,人类只能利用3%的水,但是我们还不能完全利用这3%,因为一些是冰用,最糟糕的是一部分被污染了。
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本试题收录于: 英语题库普高专升本分类
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