"Humayi is in the north wind and crosses the south branch of the Bird's Nest." The poet has produced rich associations in his extreme yearning: everything has the nature of homesickness. Birds and beasts are still like this, let alone people. These two sentences are metaphorical, and the effect is far stronger and more touching than saying them directly. On the surface, it is a metaphor for a gentleman to travel far and wide, indicating that things are human beings and feelings are human beings. At the same time, it is a metaphor for a thoughtful woman's deep affection and passionate acacia for a gentleman who travels far away.