I shouldn't have done it.*用“shouldn't have+过去分词”表示类似责备或斥责的心情,“不该……”、“要是没……”.
Oh,no!I shouldn't have done it.（哦,不!我要是不那样就好了.）
What did you do?（你干什么了?）
That was a mistake.（那是一个错误.）
I blew it.（我失败了.）
I wish I hadn't done that.
I really screwed up this time.（这次我真的给弄糟了.）
I really messed up.（我给搞糟了.）
I should have known better.（我早该弄清楚一些.）
I shouldn't have said that.*用于说了不该说的话时.
I shouldn't have said that.（我要是不说那话就好了.）
It's too late now.（现在后悔也晚了.）
I wish I wouldn't have said that.
I should have known.
I should have known.（我早该知道了.）
I acted like a fool.
I should have known better.（我早该弄清楚了.）
It was careless of me to do so.*careless 表示“没注意的”、“漫不经心的”、“粗心大意的”.
It was thoughtless of me to do such a thing.
It was hasty of me to do so.
I was careless.（我太粗心大意了.）
I regret doing that.
I regret doing that.（我后悔我做的事.）
I know what you mean.（我明白你的意思.）
I regret my action(s).
I repent my action(s).
I am sorry for what I have done.
I had no choice.
Why did you drive my car?（你为什么开我的车?）
I had no choice.（我别无他法.）
I couldn't help it.
I had no other choice.
I had no choice in the matter.
There was nothing else I couldn't have done.
It was my only choice.
I went too far.*比较常用的固定短语.
You shouldn't have done that.（你不该那样做.）
I know,I went too far.（我知道,我做得太过分了.）
I overdid it.
I was too nervous.*也可用来辩解.
Did you ask her out?（你约她了吗?）
No,I was too nervous.（没有,我太紧张了.）
I was too uptight.
I wish I had studied harder.
I regret not studying harder.（我后悔没有更努力学习.）
I should have studied harder.
I should have asked him.
I should have asked him.（我要是问他一下就好了.）
Why didn't you?（那你为什么不问呢?）
I wish I had asked him.
It would have been better to have asked him.
It slipped my mind.
Did you remember to tell her?（你没忘了告诉她吧?）
Sorry,it slipped my mind.（对不起,我不小心给忘了.）
I just forgot.
I forgot all about it.（我忘得一干二净.）