I doubt he will win or not.A. whetherB. if C. thatD. when

问题补充：

I doubt he will win or not.

A. whether

B. if

C. that

D. when

答案：

(答案→)A. whether

B. if

C. that

D. when

解析：whether …or not 是不是，whether引导宾语从句。句意：我怀疑是否他会赢。故选A.