4、Water is very important to living things. Without water there can be _ _ _ 21 _ _ _ life on earth. All animals and plants need water. Man need water, too. We need water to drink, to cook our food and to clean _ _ _ 22 _ _ _ .
Water _ _ _ 23 _ _ _ almost everywhere. Even in the driest part of the would there is some water in the air. You can not see it or feel it when it is part of the air. The water _ _ _ 24 _ _ _ seas and rivers is a liquid. The water in the air is not a liquid but a gas.
Clouds are made of water. They may _ _ _ 25 _ _ made of very small drops of water. Water, you have found,is very useful, so we must save water.