阅读下面的短文，将文中划线句子译成汉语。
Water，like air and sunshine，is very important for life（生命）．All animals and plants need water．① Without water，there can be no life on the earth（地球）．
Man（人类）also needs water．He needs it to drink，to cook and so on．It even makes up（占）the GREater part of his body．For example，the adult human（成年人）body is about 75％water，with up to 85％of brain cells（脑细胞）liquid（液体）；even teeth are 10％moisture（水分）．② The body needs a constant（经常）supply（供给）of clean water to keep healthy．
Water is almost（几乎）everywhere．③ Around 71％of the earth is covered（被覆盖）with water in the seas，the rivers and the lakes．Even in the driest places of the world， there's water in the air．
However（然而），most of water on the earth is seawater．We can not drink or useit．④ We can only drink or use less than 1％of the fresh water．
⑤ Now we are living in a thirsty world and we must keep the water clean．
Key:．
1．没有水，地球上可能就没有生命。
2．人体也需要经常供给干净的水分以保持身体健康。
3．地球表面约有71％被海水、河水以及湖水覆盖着。
4．我们唯一能饮用的淡水不到1％。
5．目前，我们正生活在一个干渴的世界里，所以我们必须保持水的纯净。
