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.But in many Muslim nations people grumbled that the Pope appeared to be regretting the reactions to the speech, but not the speech itself.
然而在许多穆斯林国家，有人抱怨说教皇似乎是在为他演讲引起的反应而不是演讲本身感到歉意。
2.Don't end up regretting what you did not do because you were too lazy or too frightened to soar.
不要到头来后悔自己因为太懒或太怕高飞而无所作为。
3.You're not regretting the impossible, you're regretting what you know you could achieve; what you should achieve.
知其不可，你不会悔恨；所悔所恨者，你知道自己能够实现，自己应该实现。
4.Only if really does not let me be sad, lets me to like regretting once more, violates mistake.
除非真的不让我难过，让我为爱再次后悔，犯下的错。
5.The son, regretting the swans, turned his head back toward the basin until a corner of the quincunxes concealed it from him.
孩子舍不得天鹅，不住地向大池回头望，直到梅花形排列的树木在拐角处遮住了他的视线为止。
6.She had been regretting the wane of a pleasant evening, but she had thought there was a half-hour more.
她一直在惋惜这个愉快的夜晚即将消逝，但她原以为还有半个小时呢。
7.Rather than regretting my foreign origin, I began to reflect on the outdated Chinese way of looking at foreigners.
我不再为我的外国原籍遗憾，而是开始反思中国人对外国人的陈旧看法。
8.Rather than regretting how the Republicans in Congress have behaved, Mr Obama should look harder at his own use of his presidential power.
与其对共和党在参议院的恶行感到遗憾，不如寄希望于奥巴马先生努力检视该如何运用自己的总统权吧。
9.Do you think she must be unhappy for life on your side, thinking to an other man, regretting what she left for you ?
你认为她会和你幸福的生活吗？思念着另一人，后悔着为了你而离开了他？
10.I said as much in the review, while regretting the missing sociology of diplomatic practice.
我在书评中也是像上面这样说过，还对该书未能从社会学视角来探讨外交实践表示遗憾。