— I'll come to listen to your speech at 9:30 tomorrow morning.— I regret to tell you that

问题补充：

— Ill come to listen to your speech at 9:30 tomorrow morning.

— I regret to tell you that by then my speech .

A. had ended

B. has ended

C. will have ended

D. will end

答案：

A. had ended

B. has ended

(答案→)C. will have ended

D. will end

解析：本题考查时态。句意：——明天早上九点半我将来听你的演讲。——我很遗憾地告诉你，到那个时候我的演讲已经结束了。句中by then指的是by 9:30 tomorrow morning，表示在将来某一时间以前已经完成的动作，要使用将来完成时，所以答案为C项。