1. This poem was written by Du Fu in memory of his friend Liu Yuxi, a famous politician and writer in the Tang Dynasty. Liu Yuxi was a famous prime minister and writer in Tang Dynasty. He served in two dynasties (Kaiyuan Dynasty and Tianbao Dynasty) successively, and served as left gleaner and foreign minister. He was modest and refused his official position many times, but he finally took charge of state affairs. Du Fu described Liu Yuxi's diligence and heavy responsibility as a prime minister with "three summonses focusing on state affairs", and expressed his admiration for Liu Yuxi's long-term benefit to the people with "two generations' dedication".
2. "Seven Joining the Army: Part IV" is a long poem by Du Fu, a famous poet in Tang Dynasty, and it is also one of the series of "Three Farewells". This poem depicts the scene of Du Fu's parting from his friends and his feelings after parting, reflects the pain and impermanence brought by the war, and also expresses his cherish of friendship and hope for the future.