Question

  The world is not hungry,but it’s thirsty. It seems strange that nearly 3/4 of the earth is covered with water but we say we are short of water. Why? Because about 97% of the water on the earth is sea water which we can’t drink or water plants directly. Human beings can only drink and use 3% of the water that comes from rivers and lakes. And we can’t even use all of that,because some of it has been polluted.

Now more water is needed. The problem is how we can avoid a serious water shortage in the future. First,we should find out ways to reuse it. Scientists are making study in this field. Today,in most large cities water is used only once and then runs to the sea or rivers,actually it can be used again. Even if every large city reuses its water,the water will still not be enough. What could people do next?

The sea seems to give us the best answer. There is a lot of water in the sea. All that need to be done is to get the salt out of the sea water. This will be expensive，but it has already been used in many parts of the world. Scientists are trying to find out a cheaper way of doing it. So you see，if we can find out a way，we’ll be no longer in danger of drying up.

根据材料内容选择最佳答案。

(   ) 51. From the passage,what percent of the  earth  is  covered with land?

A. 25%.  B.30%.  C.35%.  D.45%.

(   ) 52. Which of the following is NOT true according  to  the passage?

A. We can drink the sea water or use it directly.

B. Some water from rivers and lakes is polluted.

C. In large cities,water can be reused.

D. If we can find a cheaper way of getting the salt out of the sea water,we’ll not need to worry about water shortage.

(   ) 53. To solve the water problem,what should we do?

A. We should use all the water directly.

B. We should find out ways to reuse the     water.

C. We should get the salt out of the sea     water in  a cheaper way.

D. Both B and C.

(   ) 54. To avoid the serious water shortage,which of the following  is  the  most  important?

A. Save water and try to make good use of the water in rivers     and  lakes.

B. Don’t pollute water and keep all rivers and lakes clean.

C. Make dirty water clean and then reuse it.

D. Try to find a cheaper way to get the salt out of the sea water.

(   ) 55. What is the best title of the passage?

A. The Sea Water     B. How to Save  Water

C. The Thirsty World     D. The Polluted  Water

Answer 1

51. A   根据第一句中  3/4 of the earth is covered with water.…可知。

52. A   根据第一段+…we can't drink or water plants directly.可知。

53. D 

54. D   根据最后两句Scientists are trying to find out

a cheaper way of doing it. So you see,if we can find out a way,we'll be no longer in danger of drying up.可知 

55. C 

紧缺和如何把不能莨接使用的水资源转换成可直接使用的水资源的问题，排除了A,B和D.