-Han Yu

The lights are on at five o'clock in the middle of the night.

It is when boys are studying.

Black hair doesn't know how to study early, and

Whitehead regrets studying late.

—— Yan Zhenqing (a painter and calligrapher in the Tang Dynasty) quoted from

Persuade Learning. Great career and university questioners in ancient and modern times have gone through three realms: "Last night, the west wind withered the trees, and I went to a tall building alone, looking at the end of the world." This first realm is also. "The belt is getting wider and wider, and I don't regret it. I am emaciated for Iraq." This second realm is also. "The crowd looked for his whiteness, and when I looked back, I saw that the man was in a dim light." This third realm is also.

—— Wang Guowei (a scholar in Qing Dynasty) quoted from

A young man who doesn't work hard is sad.

young people don't know how to study hard, but old people regret studying late.

there is a way to learn from books and mountains, and there is no limit to learning from the sea.