Spring something on someone:
To suddenly tell or ask someone something when they do not expect it.
当有人问你或告诉你一件意想不到的事情时，就可以使用表达 “spring something on someone（突然告知，冷不丁地问）” 来描述这一情况。这件事情通常可能是听讯者不知道的信息或不了解的工作，因此，这个表达多用来描述一个不愉快的意外。
例句
Just as I was leaving the house, my mum sprang an extra chore on me, and I arrived late at the party.
就在我要出门的时候，我妈突然给我加了一件额外的家务活，结果我参加聚会的时候迟到了。
Please don’t spring any nasty surprises on me. I don’t think my heart can take it.
请不要突然告诉我任何让我不愉快的事情。我的心脏承受不了。
Just as we thought the deal to buy the company was concluded, our rival decided to spring a last-minute bid on us.
正当我们以为收购这家公司的交易已经达成时，我们的竞争对手在最后一刻决定出价。
