“悬崖勒马”，汉语成语，意思是在高高的山崖边上勒住马（draw [rein] in one's horse at the edge of a cliff）。比喻到了危险的边缘及时清醒回头（desist from doing something before it is too late），可以翻译为“pull back before it is too late”。

例句：

现在是你悬崖勒马的时候了。

Now is the time for you to pull back before it is too late.

犯罪分子应当迷途知返，悬崖勒马，不要在错误的道路上继续走下去。

The criminals should stop on the precipice, retract from the wrong path and not go any further.