I quoted a poem from Li Bai's Thoughts on a Quiet Night.
The ancients believed that when the moon hung in the sky, it was the day of human reunion. Poetry follows this tradition. When they live in a foreign land, they will express their homesickness by moonlight. "Looking up, I found it was moonlight, sinking again, and I suddenly thought of home." That's the idea. Looking up means looking up. The poet looks up at the moon in the sky, which is bright, perfect and beautiful. There is a full moon, but I have been away from home for more than a year, but I can't go back to my hometown to reunite with my family. At the thought of this, the poet will unconsciously lower his head, because the flood of homesickness makes him uncomfortable.