—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：
此题考查regret的基本用法。常用的句型结构有：
regret ding sth/that:对某事感到懊悔,遗憾
regret to do sth.that为要做的事抱歉,遗憾
regret to have done将来完成时
regret having done:为做过的事感到后悔，抱歉综上所述，故正确答案选择D.