1 . Water is very important to living things. Without water there can be no life on the earth. All animals and plants need water. Man also needs water. We need water to drink, to cook our food and to clean ourselves. Water is needed in offices, factories and schools. Water is needed everywhere.
There is water in seas, rivers and lakes. Water is found almost everywhere. Even in the driest part of the world, there is some water in the air. You cannot see or feel it when it is a part of the air. The water in the seas, rivers and lakes is a liquid. The water in the air is a gas, and we call it water vapor(水蒸气).
Clouds are made of water. They may be made of very small drops of water. They may also be made of snow crystals(晶体). Snow crystals are very, very small crystals of ice. Ice is frozen water. It is a solid(固体). There can be snow and ice everywhere in winter.
Water may be a solid or liquid (液体) or a gas. When it is a solid, it may be as hard as a stone. When it is a liquid, you can drink it. When it is a gas, you can not see or feel it.
Choose the best answer
1. Where can we find water?
| A．We can find water when it turns into vapor. |
| B．Water can be found almost everywhere. |
| C．We can see it in deserts(沙漠) here and there. |
| D．Water is only in seas and rivers. |
2. We can drink water
.
| A．when it is a liquid | B．when it is a solid |
| C．When it is in the air | D．When it is turned into ice |
3. Clouds are made of
.
| A．seas, rivers and lakes |
| B．a big piece of ice |
| C．very small drops of water or snow crystals |
| D．water in its solid state |
4. Water has three states (状态).
They are
.
| A．ice, snow and air | B．solid, gas and vapor |
| C．drops of water, ice and snow | D．solid, liquid and gas |
5. We must save water because
| A．crops need water | B．all living things need water |
| C．all animals need water | D．all plants need water |
