—OK, I will.

—It's dangerous. You'd better wait for your mum to come back.

    Everyone knows water is important to all living things. But do you know these interesting 1about water?

    Without water, the Earth would look 2the Moon. People can live for a long time without food, but only 3 days without water. Scientists say about 70% of the human body is made up of water. Water4 up about 83% of our blood, 75% of our brain, and 80% of our lungs(肺）. About 95% of a tomato is water, and about 80% of an apple is water. So 5can we do to help with water problems?

    Keep a shower to 10 minutes or6 time. It helps save much water. Use a broom to sweep the floor, the stair, the garage(车库），or the sidewalk instead of water.

    7throw your used water away. Instead, you can use some to water plants or run the toilets. Use a bucket(桶）of water to 8 your bike or the family car instead of water pipes.

    Use water only9you need it. Don't leave water running. Be sure to turn the tap 10when you are not using it.

    Water is very important to us. We cannot live without it.

    There is a lot of water on the Earth, but we cannot use most of it. About 97. 5% of the Earth's water is salty. Most of the fresh water is snow and ice near the North and South Poles(极).

    We can only use less than one per cent of the water on the Earth. We use water from both lakes and rivers. Some of the water evaporates and then becomes rain. Of course we use rain water for farms and other things. We use this water again and again.

    Sometimes the Earth's water is in the wrong place. There is a lot of rain in the tropics(热带地区)，but it is difficult to have farms in the tropics. Most of the land there is not very rich. Some desert land is rich, but there is only a little water in the desert.

    Water is a problem for many people in the world.

    Water is very important to living things.       (with)water, there can be no life       the Earth. All       (plant)and animals need water. Man also needs water. We need water       (drink）, to cook food and to clean       (us). Water is needed in farms, factories, offices, schools       families.

    Water is found in seas, rivers and lakes. It can be found everywhere        the world,        it can also be found in the air. We cannot see or feel the water when it is part of the air. Clouds are also       (make)of water. They are little drops of water. When water       (freeze), it becomes ice. So ice is also water.

Sorry, I                           for you to eat.

There                    people on the Great Wall.

He              Lesson Ten.

The blood on the ground                    in the burning sun.

Finally, the water             ice.