throw a curve
出乎意料地改变某事或某人的方向或进展
口语·形容意外情况
英文释义
to surprise or deceive someone
例句
The boss threw a curve when he announced the meeting was canceled at the last minute.
典故来源
源自棒球术语，投手投出曲线球使击球手难以预测，比喻出人意料的行为。