大好的天气如果突然下起雨，那么可能原本计划好的活动就不得不取消，着实令人扫兴！

当某人的计划不得不因为事或人而告停时，就可以用表达 “rain on someone's parade”，也就是汉语里说的 “泼冷水，扫兴”。

例句

I hate to rain on your parade, but you're not going home until you've finished that.

我不想煞风景，但是你完成这件事之前不准回家。

They had planned to go to the beach at the weekend, but the weather just rained on their parade.

他们原本计划这周末去海滩玩，但糟糕的天气让他们很扫兴 。

He was going to have a party on Friday, but his friends rained on his parade when they said that they were all busy.

他本想在周五开派对，但他的朋友们却泼了他一头冷水，都说太忙去不了。