Don't count your chickens before the eggs have hatched
别过早乐观，不要依赖尚未实现的事情做计划，避免失望。
劝人谨慎，避免过度乐观或提前庆祝。
英文释义
Don't make plans for something that might not happen.
例句
You might win the lottery, but don't count your chickens before they hatch.
典故来源
源自伊索寓言《挤奶女工》，女工幻想卖鸡蛋发财却打碎篮子，警示空想。