Don't count chickens before they hatch
不要对未确定结果的事情过早下结论或做假设，避免盲目乐观。
劝告他人不要过早下结论或做计划时使用。
例句
She's already planning the party, but I told her not to count her chickens before they hatch.
典故来源
源自伊索寓言，讲述一个农妇在鸡蛋未孵化前就幻想卖鸡赚钱，结果蛋被打碎。