cold day in hell
极为罕见的事件或情况不太可能发生
口语·强调某事绝不可能发生
英文释义
Something that is highly unlikely to happen
例句
It'll be a cold day in hell before I apologize to him for something I didn't do.
典故来源
源自基督教地狱火热的传统观念，地狱变冷象征不可能发生的事，强调极端罕见。