1. 根据短文内容，完成下列各题。

    Our earth is in trouble. (2) Our drinking water is becoming dirtier, and the air is not as clean as before. People and factories are polluting the air, rivers and lakes and seas. You may think that there is nothing you can do to help. That's not true. There are many things you can do to help the earth. Cars burn gasoline. This will produce a lot of CO₂ into the air. Some people believe that too much CO₂ is making the earth warmer than ever. They think CO₂ thins the clouds above us. The clouds keep us away from the strongest sunlight. So try to walk, ride a bike or take a bus. And if you drive a car, drive at a steady speed. This can save some gasoline. The biggest energy use at home is for keeping (1) ___________or____________. So turn the air conditioner off when you don't need to use it. Use lights that save energy. Use fewer things that cannot be used again. When you buy something, consider those made from things that can be used again first. A lot of water is needed for a shower. In one week a family uses as much water for showers as a person drinks in three years! Take shorter showers. This can cut the use of water.

1. （1） 在（1）处填入适当的单词（每空一词）：；
3. （2） 将句子（2）译成汉语：
5. （3） 回答问题：How can we save water according to the passage?
7. （4） 找出“If there is too much CO₂ in the air, the earth will become warmer.”的同义句。
9. （5） 从文中找出能概括本文大意的句子。