1. 阅读理解

    Most cars run on gas. Gas cars work very well. But there is a problem. Cars that run on gas make the air dirty. The dirty air is not good for people, animals or trees. Gas cars make the air dirty for all living things. What can we do? We can drive electric cars!

    Electric cars do not use gas. These cars do not make the air dirty. These cars have batteries that power their motors(马达). The batteries can be charged（充电）many times. They can be used again and again. This makes electric cars great. But electric cars have problems too. They are slower than gas cars. They are also very quiet. This means that some people can't hear them when they go by. They may not think a car is coming. So they have to be careful.

    People are looking for ways to make electric cars better all the time. Maybe one day all cars will be electric. That would be much better for the world.

1. （1） What's the problem of the cars that run on gas?

   A . They are too big. B . They are noisy. C . They are too small. D . They make the air dirty.
3. （2） What does the underlined word "they" refer to(指代）?

   A . Gas cars. B . Some people. C . Electric cars. D . The batteries.
5. （3） Why do some people have to be careful about electric cars?

   A . Because they are quiet. B . Because they are fast. C . Because they are too big. D . Because they make the air dirty.
7. （4） The writer hopes            .

   A . no cars will be electric B . gas cars can become better C . all cars will be electric D . gas cars can become slower
9. （5） What's the best title for the passage?

   A . The problems of gas cars B . People who study cars C . The problems of electric cars D . Gas cars and electric cars