51.  And these water resources are never used up, so we can use fresh water without any trouble .

52.  And these years, population has increased quickly, and fresh water is used by more and more people.

53.  Third, we should use water economically so that less water is wasted.

54.  So most of us don't think that there is any problem in using fresh water, and frequently some people waste plenty of fresh water in their daily life.

55.  So I think that we should be more careful when we use fresh water.

56.  And factories especially the big factories should use fresh water more economical and be careful not to pollute it.

57.  People always think fresh water won't be used to an end .

58.  So people think fresh water can be used for ever.

59.  More and more factories came out to use water, and the demand of water is rising.

60.  Second, we must confine the industry using water and guide the factories to saving water as far as possible.