【题目】It is obvious to the students ______ they should get well prepared for their future.
A. as B. which C. whether D. that
在线课程【答案】D
【解析】
试题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。