Model 10 The Global Shortage of Fresh Water
Most people believe that the supply of fresh water on the earth is inexhaustible. City dwellers are used to having as much clean water as they want coming out of the kitchen tap. And if you go into the countryside in most places you will see a wide variety of sources of water—rivers，wells，and even glaciers. It seems that they could never be used up.
But the truth is that the world is short of fresh water. The rapid growth of the rural population，the rising demand for water by industry and the increasing rate of pollution of water sources means that there is a global threat of massive water shortages. Already in some major cities there is not enough fresh water to satisfy the daily needs of their inhabitants.
Therefore，it is an urgent task for us to find new ways to save water.First，we should be careful not to waste water. Second，scientists should be encouraged to improve methods of desalinating seawater and purifying polluted water. And third，industry must make extra efforts to reduce the use of fresh water.