Americans love cars. They have more than 250 million (百万) cars ---about one car for every 1.2 people. But these cars cause (引起) too much air pollution. Even children know that cars need gas (汽油)  to run. If there is no gas, today's cars will become tomorrow's about the cars in the future, they usually think of hydrogen (氢气) cars, electric (电的) cars and flying cars.
Hydrogen cars might be the cars of the future. They don't cause pollution and the hydrogen turns into water after it is used. The first hydrogen car was made by Honda. It was very expensive and didn't run very far.
There are some electric cars on the market, but they can't run very far or very fast. In the future, there will be a lot of electric cars on the road. When the batteries (电池) are better and cheaper, electric cars will become more popular.
There will be another kind of car --- flying cars. They will be able to run in the air. But now there is only one company, MDI, making this kind of car.
We can know from the text that there are about     _ people in American.
A. 250 million    B. 300 million      C. 208 million
Hydrogen turns into        after it is used.
A. water          B. air                   C. gas
Which of the following is TRUE about electric cars?
A. They can run fast but not very far.
B. They are very popular with people now.
C. They are still too expensive for people to buy.
How many kinds of cars are mentioned in the passage?
A. Two                 B. Three                 C. Four
What is the best title for the text?
A. Cars in the future.
B. Americans and cars.
C. Air pollution.