for a rainy day
以备不时之需；未雨绸缪；居安要思危.，有备无患；以应付艰难时刻或困境
put something aside for a future time in which it may be needed; to save some of your money in case there are serious problems in the future.
save sth for a rainy day指的是“以备不时之需、有备无患”
常用于save money for a rainy day
I earned extra money babysitting. I’ll save it for a rainy day.
我帮人照看孩子挣了点钱，我要存着等以后需要的时候再用。
I'll put the rest in the bank for a rainy day.
我要把余款存入银行以备不时之需。
She saved money for a rainy day.
她存钱以备不时之需。
He put away some money for a rainy day.
他储蓄一些钱以备不时之需。
Luckily Alice had saved money for a rainy day.
幸好爱丽丝未雨绸缪早有准备。
I know you want to buy a new TV, but you should really save that money for a rainy day.
我知道你很想买台新电视，但你真应该把这笔钱存下来以备不时之需。
Now that it's pouring, in other words, American households have decided to save for a rainy day.
现在，已成滂沛成潮，也就是说，美国家庭已决定积谷防饥。
In poorly developed financial systems, households find it hard to borrow and so need to save for a rainy day.
在不发达的金融系统里，家庭因借贷不易而需要未雨绸缪。
Actually I bought the car insurance in advance, you know, to save for a rainy day.
其实我提前买了车险，为的是未雨绸缪。
Now many young family would have basic pension plan to save for a rainy day.
现在很多年轻家庭会购买养老保险，以备不时之需。
Don't spend all your money on that new phone. Save it for a rainy day.
不要把所有的钱不要都花在那部新手机上。留着以备不时之需。
I have a sufficient rainy day fund to sustain me until I find the right opportunity.
我有足够的基金在穷困时期维系我，直到我找到合适的机会。
实战练习，选择正确的选项：
1. What does the idiom "rain cats and dogs" mean?
a) It's raining heavily
b) It's a sunny day
c) It's snowing
d) It's windy
2. If you ask for a rain check, what are you asking for?
a) To go outside and enjoy the rain
b) To cancel a plan
c) To reschedule a plan
d) To buy an umbrella
3. What does the expression "under the weather" mean?
a) Feeling sick or unwell
b) Enjoying a sunny day
c) Being outside in the rain
d) Feeling happy and energetic
4. What does the phrase "Rain or shine" mean?
a) It only matters if it's raining
b) It doesn't matter what the weather is like
c) It only matters if it's sunny
d) It only matters if it's snowing
5. If you "save it for a rainy day," what are you doing?
a) Saving money or resources for a future time of need
b) Waiting for a sunny day to use something
c) Enjoying something immediately without delay
d) Ignoring something completely
6. What does the idiom "it never rains but it pours" mean?
a) It only rains during the night
b) It always rains when you don't want it to
c) It only rains during the day
d) When things go wrong, they tend to keep going wrong
答案：
1. a) It's raining heavily
2. c) To reschedule a plan
3. a) Feeling sick or unwell
4. b) It doesn't matter what the weather is like
5. a) Saving money or resources for a future time of need
6. d) When things go wrong, they tend to keep going wrong