I'm sorry -----so long.I forgot to tell you in advance that I would have a meeting this afterno

I'm sorry -----so long.I forgot to tell you in advance that I would have a meeting this afternoon
B.to keep you waiting C.to have kept you waiting 感觉两个都对啊，，书上和网上答案一个说B一个说C，而且两个都能用翻译器翻译，，应该选什么

选C，过去完成时。
I'm sorry _____ so long.如果单单从这句来讲，那么B和C都是可以的。

但是后边加了I forgot to tell you in advance that I would have a meeting this afternoon，
表示：过去的“我”没有告诉“你”，“我”今天下午有一个会议。
因为这动作是在过去完成的，所以需要用过去完成时，故选C。

C 因为so long，很长时间，这种一般会和完成时连用，所以用to have kept you waiting

你好！ I'm sorry -----so long.I forgot to tell you in advance that I would have a meeting this afternoon B.to keep you waiting C.to have kept you waiting都对！一种用了普通的不定式，一种用了不定式完成形式。 仅代表个人观点，不喜勿喷，谢谢。