It would be doing me knight service if you keep your eyes fixed upon them, and remember them every minute of the day, and tell me directly I drop one.
如果你的眼睛盯着它们， 每天每分钟都记住它们， 并直接告诉我我掉了一个， 那就是在为我服务。
英语百科
Knight-service
（重定向自Knight service）
Knight-service was a form of Feudal land tenure under which a knight held a fief or estate of land termed a knight's fee (fee being synonymous with fief) from an overlord conditional on him as tenant performing military service for his overlord.