Is necessary them to stop every two hours?A. that; for; restingB. that; of; to restC. it;

问题补充：

Is necessary them to stop every two hours?

A. that; for; resting

B. that; of; to rest

C. it; for; to rest

D. it; of; resting

答案：

A. that; for; resting

B. that; of; to rest

(答案→)C. it; for; to rest

D. it; of; resting

解析：it is necessary for sb to do sth “对于某人来说有必要做某事”，stop to do 停下来做另一件事，stop doing停止做某事，答案C。