regret to do對將要做的事遺憾，regret doing對做過的事遺憾、后悔。例如：

I regret to have to do this， but I have no choice. 我很遺憾必須這樣去做，我實在沒有辦法。

I don’t regret telling her what I thought.我不為告訴她我的想法而后悔。

典型例題

——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

答案：D.regret having done sth. 對已發生的事感到遺憾。regret to do sth. 對將要做的事感到遺憾。本題為對已說的話感到后悔，因此選D.