格言大意：一寸光阴就像一寸金子那样宝贵，甚至一寸金子也无法买回一寸光阴啊。

Main Idea: Time is as precious as gold but even with gold you can’t redeem time when it flows away.

司马光的“警枕”（The “warning pillow” of Sima Guang）

    北宋大学问家司马光从小用功读书。做官以后，每天在工作之余，还埋头研究历史书籍，决心编写一部按年代编排的历史书。为了抢时间，避免睡过头，他特地设计了一种圆的木枕头。睡觉时一翻身，枕头就会滚走，将自己弄醒，好起床继续工作。司马光把这种枕头叫“警枕”。他终于完成了巨著《资治通鉴》。
   Sima Guang, a great scholar in the Northern Song Dynasty, studied very hard when he was young .After he became a government official, he still buried himself in historical literatures in his spare time. He decided to compile a history book in which all the historical events would be arranged in chronological order. In order to save time and avoid oversleeping, he designed a special round wooden pillow. If he turned in his sleep, the pillow would roll away, waking him up so that he could get up and go on working. Sima Guang called it “warning pillow”. He completed the great work named Zi Zhi Tong Jian finally.