91.  The polluted water can't be used by people.

92.  So the water is used for people's drinking is not enough .

93.  Industry also need lots of water and the anomt of using water is increasing.

94.  Many lakes and rivers are pulluted , so we can't use the water in these lakes or rivers.

95.  We must develop our science to use water in oceans.

96.  When they are using water, they never have the idea that they should be care of the "inexhaustable " blood of nature.

97.  So they use some water to produce.

98.  Such as use the water many times through circle in some factories.

99.  So you can use fresh water as you want.

100.  The first, we should use fresh water little.