How to express regret 怎样表达懊悔

What a foolish thing I've done! 我真是做了件傻事。
What a stupid man I am! 我真是个大傻瓜。
Why hadn't I thought of it? 我怎么没想到那一点呢？
Why on earth could I do such a laughable thing ? 我为什么会做这么令人可笑的事情呢？
Why do I always do things in a rush? 我为什么总是冲动？
Why did I tell these thing to him? 我为什么要把那些事告诉他？
Why don't I thind before I act? 我为什么不三思而后行？

Why didn't keep silence? 我为什么不保持沉默呢？
How could I tell him such kind of things?这种事情我怎么能告诉他呢？
How could I give such a foolish answer? 我的回答怎么那么蠢呢？
How could I do such a silly thing? 我怎么能做这种傻事呢？
How could I miss it ? 我怎么错过了这个机会呢？
How I longed for the power to unsay these tactless words! 我多么希望没说那些不得体的话啊！
I regret having bought the expensive car. 我后悔买了这辆昂贵的汽车。

I regretted my decision. 我后悔自己的决定。
I regret that you see it in that way. 你用那种方式看待这个问题，我感到很贵憾。
I regret to tell you that I have no news for you. 很遗憾地告诉你，我没给你带来新消息。
I've always regretted making friends with him. 我一直后悔不该跟他交朋友。
I should think today and speak tomorrow. 我应三思而后行。
I should think twice. 我应三思。
I should have thought of that. 我本应当想到那一点的。

I wish I'd never said that. 我要没说那些话多好啊。
I wish it weren't true. 我多么希望那不是真的。
I wish I had watched the game. 我真希望我观看了这场比赛。
I'm terribly sorry. 太遗憾了。
If I had been more considerate. 我本应再想得周到些。
If it hadn't snowed so heavily, I should have gone there. 要不是下这么大的雪，我就去了。
If only I hadn't lost it . 要是没把它丢了多好啊。

If only he were here! 他要是在这里多好啊！
If only I hadn't missed the chance. 我要是没错过这个机会多好啊。
If only I had thought more. 我要多想想该多好啊。
It's a pity that you missed the good opportunity. 你错过了这个好机会太遗憾了。
It's regrettable that he didn't come. 他没来真遗憾。
Regretfully,we can't go with you. 遗憾的是我们不