— “May I speak to your manager Mr. Williams at five o’clock tonight?”— “I’m sorry. Mr Will

问题补充：

— “May I speak to your manager Mr. Williams at five o’clock tonight?”

— “I’m sorry. Mr Williams to a conference by then.”

A. will have gone

B. had gone

C. would have gone

D. has gone

答案：

(答案→)A. will have gone

B. had gone

C. would have gone

D. has gone

解析：

这题考查时态， by“到什么时候为止”，和相应的完成时连用，根据上下文，时间是：by then指“到今晚五点为止”，所以用将来完成时。