The world is not only hungry,but also thirsty for water.About 97%of water on the earth is sea water,or salt water.Man can only drink or use the other 3%fresh water which comes from rivers,lakes,and underground.On the other hand,because the number of people in the world is becoming larger and larger,more and more fresh water is needed.So water shortage becomes a big problem.
How can we work out this problem?Scientists have found some ways to turn salt water into fresh water.One important way is to boil sea water with high heat until vapor rises,leaving the salt.In this way,a lot of fresh water can be made quickly.
But heating is not the only way to get fresh water.Other ways are tried,such as digging deep wells,keeping rain water and preventing rivers from being polluted.
Which way is the best?To get the most fresh water for the least money is the best.
1. The best title for this passage is()
ADifferent Ways of Making Water in Different Places
BHow to Use Fresh Water in Our Daily Life
CThe Importance of Saving Water
DThe Ways to Get Fresh Water