51.  For example, in the course of our English study, there is a new word that we didn't learn ago , but we can guess its mean according to our learning knowledge.

52.  Hence, we can know its mean .

53.  For example, in the English learning, you want to master a word, first you must read it no and then, on the other hand you must understand its uses .

54.  The industry which has accelerated its development requires more and more water.

55.  In my opinions, first, we should quite aware of the shortage of the fresh water and preserve its source.

56.  Fresh water is so limited that some scientists have alermed us of its serious shortage.

57.  And now, we have lost many sources of water because of its pollution.

58.  People think that freash water can not be in its end and there are plenty of water on the earth.

59.  And its great demand of water, and the worse pullution , you'll see that to some extent .

60.  First, we should aware of the increase of population and make rules to prevent its increasing .