填空题
- A. visibility is reduced
- B. all of the effects of pollution on the human body
- C. pollution is not controlled
- D. who is responsible for it
- E. man's behavior
- F. more money should be spent in solving the problem
填空题
Air pollution may lead to airplane accidents because 1.
填空题
Scientists are trying to find a link between pollution and 1.
填空题
Scientists have not yet determined 1.
填空题
The author suggests that before air pollution becomes more serious, 1.