We don’t know the meeting will be held soon.A. whenB. whatC. whetherD. since

问题补充：

We don’t know the meeting will be held soon.

A. when

B. what

C. whether

D. since

答案：

A. when

B. what

(答案→)C. whether

D. since

解析：考查宾语从句。句意：我们不知道会议是否会马上召开。是否用whether，选C。