有一次，一位外教老师，在大晴天的感叹道：I've been really bad lately. It's really a rainy day.

有同事回应：“Wow! It is raining? Awesome!”

外教老师突然对他白了一眼，无言地走开了……

神马情况？“A rain day”难道不是“下雨天”？

原来，a rainy day除了有“下雨天”的意思，还表示“不如意的日子”，“穷困的日子”。

eg：

I know you wanna 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。

在这里，需要注意：“rainy day”一般和for搭配使用，意为“以备不时之需”。

如：save/keep money for a rainy day就表示

to save money for a time when it might be needed unexpectedly.

存钱以备不时之需；有备无患；未雨绸缪

Luckily she had saved some money for a rainy day.

幸好她未雨绸缪早有准备。