Source: Cao Pi and Wu's Quality Book: "Young people should really work hard. A year has passed, how can they climb? " The ancients thought it was good to travel by candlelight at night. "Wu Zhi's book is a famous essay in Wei and Jin Dynasties. Xelloss and Cao Zhi each have one, which is a letter written by Xelloss and Cao Zhi to Wu Zhi respectively. In the history of literature, Cao Zhi's literary achievements are higher than Cao Pi's. The Quality Book written by Cao Pi and Wu is not only generous, but also brilliant in literary talent and deep in feelings, which is more famous than Cao Zhi.