translation.en: Well, its hinges battle with gravity, and gravity will always win in the end, so why not have it pivot on the center where it can stay balanced?
translation.zh: 通常它被合页固定，以对抗重力， 不过最终总是重力获胜， 那么为什么不把枢轴装在中间， 使它自身能够处于平衡状态？