Although the word is hungry， it is even thirstier． While nearly 3/4 of the earth is （1）c　　with water， we are short of drinking water． This is because about 97% of the water on the earth is sea water．

    How can we （2）a　　a serious water shortage？ First， we should save water and not waste it． Then， we should protect our water resources and not pollute them． Lastly， we should discover ways to reuse water． Scientists have got some achievements in this field． But people's need for water is increasing day by day． We （3）s　　don't have enough water． What else can we do？

    The sea seems to have the best answer． There is （4）p　　of water in the sea， but we need to take the salt away from the sea water． This is very expensive． If scientists can find （5）c　　 ways to do it， we can solve the problem of the shortage of water．