I want to know you will be back before 8:00 tomorrow morning.A. thatB. whereC. whetherD.

问题补充：

I want to know you will be back before 8:00 tomorrow morning.

A. that

B. where

C. whether

D. when

答案：

A. that

B. where

(答案→)C. whether

D. when

解析：本题的含义是我想知道明天早晨八点前你是否将要回来，whether引导一般疑问句，表示是否的含义，故本题选C。