I was giving a talk to a large group of people the same talk I to half a dozen other grou

问题补充：

I was giving a talk to a large group of people, the same talk I to half a dozen other groups.

A. was giving

B. am giving

C. had given

D. have given

答案：

A. was giving

B. am giving

(答案→)C. had given

D. have given

解析：根据语境可知had given的动作发生在was giving之前