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

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：

此题提供的语境是：我当时正在给一群人作报告，这个报告我曾给其他若干批人讲过。由于was giving为过去进行时，而“曾给其他若干批人讲过”显然发生在was giving这一过去时间之前，故用过去完成时，即答案选C。