Many people believe that the world’s supply of fresh water will never be used up. They think that fresh water comes from such a variety of sources that it is always sufficient for use. Such an opinion leads to a shocking waste of water.

　　As a matter of fact, the earth is short of fresh water. Furthermore, with the rapid growth of the world population, the rising demand for water by industry, and the serious pollution of our surroundings, the world is facing the ganger of running out of fresh water. Actually, in some big cities, fresh water can not meet the daily needs.

　　Therefore, to find new ways to save water is an urgent task. First, we should pass strict laws to control any waste of water. Second, scientists must work even harder to purify sea water, and try to find substitute to reduce the use of fresh water.