| A.Americans are used to travelling by cars |
| B.American public transportation is growing worse |
| C.American car industry caused disastrous road accidents |
| D.American people’s health is threatened by automobiles |
| A.Americans prefer cars to anything else |
| B.Americans are interested in fast automobiles |
| C.kerosene-burning engines cause more problems |
| D.kerosene-burning engines are green transportation |
| A.technology is always good for people |
| B.technology is a sword with two sides |
| C.more attention should be paid to social effects |
| D.US doesn’t care about the environment at all |