21.  On the other hand, we shall try to use sea water instead of fresh water or get fresh water from sea.

22.  For instance, when it rains we have plenty of fresh water, and we can get fresh water from river or the ice on mountain .

23.  People alway think that there have a lot of fresh water on the earth, we can get fresh water from river well rain etc. so people ofter waste it, we can see this every where .

24.  Then the side effects of the water pollution made fresh water hard to get.

25.  As a result, many people take it for granted that fresh water can be got whenever and it can not be run out of .

26.  People always think that they can get fresh water from rain water and river water.

27.  We can get fresh water from rain, wells, rivers and so on.

28.  We can get fresh water from slat water because the water in the sea will never be used up.

29.  Man can get freash water from rivers, lakes, wells etc.

30.  It seems impossible that freash water will be used up.