题目内容：

I'm sorry to have kept you waiting so long 和i' m sorry to keep you waiting so long 有啥区别

优质解答

I'm sorry to have kept you waiting so long.to have kept you waiting so long.不定式的完成形式表示【等待的动作已经结束】.I' m sorry to keep you waiting so long.to keep you waiting so long.不定式的一般形...