[单选] A Water is the root（根本）of our life． No one can live without water． On the one hand， although about seventy-two percent of the world is covered with water， about ninety-seven percent of it is sea water or salt water， so the water we can drink is really limited． On the other hand， because the number of people in the world is becoming larger and larger， more and more drinking water is needed． We should do something to save water in our everyday life． Try to fix broken taps or leaky（漏的） toilet at your home． Turn off the tap as much as you can-don"t use running water to wash your hands， wash vegetables and so on． Never pour away waste water because you can use it to do other things， such as watering a plant or a garden． Do not often water your lawn（草坪）． As a general rule， lawns only need watering every 5 to 7 days in summer and every 10 to 14 days in winter． Stop taking long baths and have short showers．1．People can only drink about（）of the water on the earth．