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。

《牛津词典》

It was one of those moments which I live to regret now.

这将是我一直感到遗憾的若干时刻之一。

youdao

Start doing it. In 40 years from now what is it that you will regret not having accomplished, appreciated or attempted?

从现在开始的40年里，你将会后悔还没做什么，没欣赏什么或者没尝试什么吗？

youdao

Publishers who chose that business plan might regret it now, but they might not have had much choice.

VOA: special.2009.04.20

It is something they now deeply regret, because,she says,"the promises of the Orange Revolution were not kept."

VOA: standard.2010.02.14

Consider also those poor souls who bought a lesser beast and now regret it.

FORBES: Five iPad 3 Rumors That Just Might Be True

What you will see in the show are the things you probably disposed of (who thought the '70s were anything?) and now you will regret it.

WSJ: When the Outrageous Became Mainstream

Ace got it, and now they want to make them regret it.

FORBES: Who's Afraid Of Brian?