It is obvious to the students they should get well prepared for their future.A. asB. whic

问题补充：

It is obvious to the students they should get well prepared for their future.

A. as

B. which

C. whether

D. that

答案：

A. as

B. which

C. whether

(答案→)D. that

解析：考查名词性从句用法。本题中的it是形式主语，真正的主语是后面的that they should get well prepared for their future. that在句中不充当任何成分，只起引导作为。故D正确。