regret doing/to do

　　regret to do　对要做的事遗憾。　(未做)

　　regret doing　对做过的事遗憾、后悔。　(已做)

　　I regret to have to do this, but I have no choice.

　　我很遗憾必须这样去做，我实在没有办法。

　　I don't regret telling her what I thought.

　　我不为告诉她我的想法而后悔。

　　典型例题

　　——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. 对已发生的事感到遗憾。regret to do sth. 对将要做的事感到遗憾。本题为对已说的话感到后悔，因此选D.

　　感官动词 + doing/to do

　　感官动词 see, watch, observe, notice, look at, hear, listen to, smell, taste, feel + do 表示动作的完整性，真实性;+doing 表示动作的连续性，进行性

　　I saw him work in the garden yesterday.

　　昨天我看见他在花园里干活了。(强调"我看见了"这个事实)

　　I saw him working in the garden yesterday.(强调"我见他正干活"这个动作)

　　昨天我见他正在花园里干活。

　　典型例题

　　1)They knew her very well. They had seen her ___ up from childhood.

　　A. grow B. grew C. was growing D. to grow

　　答案：A.因题意为，他们看着她长大，因此强调的是成长的过程，而非正在长的动作，因此用see sb do sth 的句型。

　　2)The missing boy was last seen ___ near the river.

　　A. playing B. to be playingC. playD. to play

　　答案A. 本题强调其动作，正在河边玩，应此用see sb. doing sth句型。