all cats are grey in the dark
暗中看来，所有的猫都是灰色的
书面语·比喻外表差异被忽略
英文释义
when it is not possible to see or perceive differences, appearances or distinctions become irrelevant
例句
In the dim light of the club, all cats are grey in the dark, so I couldn't tell who was who.
典故来源
源自古老谚语，强调在黑暗中无法区分颜色或特征，比喻外表差异在特定条件下无关紧要。