Most scientists seem to agree that certain limit should be set on consumption(消费) of cars

问题补充：

Most scientists seem to agree that certain limit should be set on consumption(消费) of cars to ease air pollution.

A. a; the

B. /; the

C. the; /

D. the; the

答案：

(答案→)A. a; the

B. /; the

C. the; /

D. the; the

解析：A 考察冠词。第一空a certain=some；第二空加定冠词表示特指。句义：许多科学家倾向于同意为了减轻空气污染，应该对汽车消费设定一些限制。