51.  I think the following three points are important: First, we must be fully aware of that fresh water is limited and we are facing a serious problem.

52.  A large of quantily of factories and firms are built they need plenty fresh water .

53.  For people's living, we must realize the global shortage of fresh water at first; The second one, we must control the use of the fresh water reasonablly ; The third one, also the important one, we must protect the sourse of fresh water in any way .

54.  But there is only 3 percent of all the water on the earth we can make use of because 97 percent is sea water or salt water.

55.  In fact fresh water is very short of.

56.  So what we can make use of become less and less.

57.  Second pollution of water should be Decreased or got rid of.

58.  Even , we have many rivers to be made use of.

59.  Every one of us should do from himself, do from now , saving a drop of water .

60.  As you know, the population of would increased quickly.