71.  Firstly, overpopullation has caused the fact that there are more and more people who will need much fresh water year by year.

72.  Worst of all, the water pollution make much water not be used .

73.  Increasing population, serious pollution, and much water used in industry lead to the present result.

74.  Much fresh water source is made dirty that it is unfit for drinking or using by the factories, so we have not enough fresh water actuarily .

75.  Last , pollution becomes serious and much water from the polluted rivers can't be used.

76.  In addition, someone thinks there is much under-ground water.

77.  Third, water pollution leads to the fact that much water is greatly polluted and they can no more be used.

78.  What's more, water pollution makes much water unfit to use any more.

79.  There are much water in rivers, lakes and so on.

80.  They think such a fact that there are many rivers and much rain in the world.