怎奈良宵短
[zĕn nài liáng xiāo duăn]
The phrase '怎奈良宵短' expresses regret about the fleetingness of a beautiful night. '怎奈' means how can one endure, '良宵' refers to a wonderful night usually with pleasant memories, and '短' implies short. It is commonly used in a romantic or sentimental context.