.—You were brave enough to raise objections at the meeting.
—Well, now I regret _ that.
A. to do
B. to be doing
C. to have done
D. having done
网友回答
A. to do
B. to be doing
C. to have done
(答案→)D. having done
解析：regret to do sth意为对将要做的事表示遗憾,而regret doing/having done sth意为对做过的事情表示遗憾。
【标签】非谓语动词