If you don't do it now, you'll only regret it .
你如果现在不做，以后一定会后悔的。
The decision could be one he lives to regret .
这一决定也许会有让他后悔的一天。
‘I've had a wonderful life,’ she said, ‘I don't regret a thing.’
“我一辈子生活得很好，”她说，“我没什么可遗憾的。”
He bitterly regretted ever having mentioned it.
他非常懊悔提起那件事。
I deeply regret what I said.
我非常后悔说了那些话。
I regret that I never got to meet him in person.
很遗憾我始终没能见到他本人。
used to say in a polite or formal way that you are sorry or sad about a situation
The airline regrets any inconvenience.
航空公司对所造成的任何不便表示歉意。
I regret that I am unable to accept your kind invitation.
很遗憾，我不能接受你的友好邀请。
We regret to inform you that your application has not been successful.
我们很遗憾地通知您，您的申请未获通过。
It is to be regretted that so many young people leave school without qualifications.
遗憾的是那么多年轻人肄业离校。
It is with great regret that I accept your resignation.
接受你的辞呈，我感到非常遗憾。
She expressed her regret at the decision.
她对这个决定表示失望。
a pang/twinge of regret
一阵痛悔之情
I have no regrets about leaving Newcastle(= I do not feel sorry about it) .
我一点也不后悔离开纽卡斯尔。
What is your greatest regret(= the thing that you are most sorry about doing or not doing) ?
你最大的遗憾是什么？
He gave up teaching in 2009, much to the regret of his students.
他于 2009 年放弃了教学，这使他的学生深感遗憾。
1.遗憾,抱歉;后悔,悔恨;痛惜,惋惜,哀悼 (at; for; over; of)
2.〈美〉(对于邀请等的)婉言辞谢
1.悔恨,后悔,懊悔(过错,失去的机会等);以(不能...)为憾,抱歉,抱憾
2.怀念,想念(快乐的童年,故乡等);悼念,哀悼(死去的亲友等)
1.a feeling of sadness about something that has happened; a feeling of sadness about something that you wish you had not said or done
1.to feel sorry or sad that something has happened; to feel sorry or sad about something that you have said or done
1.I regretted that I had not told him everything first.
我真后悔没有一开始就把一切告诉他。
2.I have never regretted like this, I have never been so eager to say a fluent English.
我从来没有如此后悔，我从来没有如此渴望说一口流利的英语。
3.But that has not been a surprise, and there has never been a moment when we regretted the decision to buy the club.
但那没有什么值得令人吃惊的，这丝毫不会让我对购买利物浦一事感到遗憾。
4.He said many things about economy and a balanced budget that he must have regretted afterward.
关于节约和平衡预算的事，他谈了许多，这是他后来必定要懊悔的。
5.Obama said he regretted his comment to Clinton in that debate that she was "likable enough" had been interpreted as a dig at her.
上场辩论中，奥巴马评论克林顿“足够可爱”，这在后来被诠释成对她的挖苦，对此奥巴马表示道歉。
6.Tom so regretted his misunderstanding of his girlfriend that he went down to his knees in front of her, begging for her merry.
汤姆如此后悔自己对女友的误解，以至于跪在女友的面前乞求她的宽恕。
7.Although he failed to win another world championship, Liu said he regretted seeing his friend and rival disqualified.
刘翔说，虽然未能再度摘得世界冠军，但看到他的朋友和对手被取消金牌资格，他感到遗憾。
8.The company said it did not accept liability , but regretted any distress caused to the local population by the waste dumping.
该公司称，他们不为此事承担责任，但是为垃圾倾倒事件为当地人民带来的苦恼表示遗憾。
9.But on his way to the mill Angel regretted his coldness. He wished he had been kinder to her and kissed her once at least.
但是在去往面粉厂的路上，安吉乐对自己的冷酷无情感到后悔。他真希望自己刚才能对她好一些，至少吻她一下。
10.To choose their own way, kneeling down to . . . in my dictionary has never been "regretted" the word.
自己选择的路，跪着也要走下去…在我的字典里从来没有“后悔”这两个字。