悬崖勒马 [- - lè mǎ; - ái lè mǎ]rein in on [at] the brink of the precipice — avoid imminent disaster; desist from doing sth. before it is too late; draw [rein] in one's horse at the edge of a cliff; pull back [reform] before it is too late; stop one's horse on coming to the precipice; stop on the edge of the precipice and not go any farther; wake up and escape disaster at the last moment; ward off disaster at the critical moment:•¶ 提出抗议， 要他们悬崖勒马， 停止挑衅 lodge a protest demanding that they rein in on the brink of the precipice and stop all provocations
•¶ 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.