Keep something for a rainy day

Keep something for a rainy day.   未雨綢繆

單字學習
Keep：保持
something：某物
rainy：下雨

延伸閱讀

當你聽不懂對方說的英文，有三句話不能說

Every cloud has a silver lining. 塞翁失馬，焉知非福