My dear Teachers,fellow students and friends: Good afternoon. As we all know, the earth is a planet almost covered by water,and it is water made every thing on the earth lively.Water is also one of the important part of our environment.Though,is there really so much water for us to clean,to produce many things,to play with? how much water are there on the earth then? Most of (共 2909 字) [阅读本文] >>