Giải thích :
save (something) for a rainy day and put something aside for a rainy day; hold something back for a rainy day; keep something for a rainy day
I've saved a little money for a rainy day. Keep some extra allowance for a rainy day.Fig. to reserve something--usually money--for some future need.
See also: day, save
(McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.)
save (something) for a rainy day
to keep an amount of money for a time in the future when it might be needed She has a couple of thousand pounds kept aside which she's saving for a rainy day.
dành dụm phòng khi túng thiếu, tích cốc phòng cơ (theo tratu.vn)
http://idioms.thefreedictionary.com/...or+a+rainy+day
Ví dụ :
1/ They made little effort to put anything aside for a rainy day.
2/ Take this, my friend . You're going to need that money for a rainy day.
