Water has three states----liquid, solid and gas. When its temperature gets lows than 0'C, it will freeze intoice and become a solid. And when water is heated to 100'C, it will form steam and become a gas. Therefore ice is the solid form of water and steam is water in the form of gas.
Water is very important to living things. Without water there could be no life on the earth. All animals and plants need water. Man also needs water. 65 percent of our body is water, and 85 percent of our blood is water, too. Maybe we could live 80 days without food. But we could live only ten days without water.
Unfortunately, water has now been polluted by rnan. Poisonous chernicals and industrial waste have been dumped into river, lakes and oceans, making water dirty everywhere in the world. Although about 70 percent of the earth are covered with water, there are many places in the world still running out of water. As the famous lines goes:
Water, water, everywhere, No any drop to drink.
So we should take drastic measures to deal with this problem so as to avoid a serious worldwide water shortage in the future.