Autumn water in Zhuangzi. "Frog at the bottom of the well" refers to a frog at the bottom of the well who thinks that the sky is only as big as the wellhead, which is a metaphor for a short-sighted person. The word comes from "Frogs at the well can't talk to the sea, but stay in vain" in Zhuangzi Qiushui, another long article in Zhuangzi. The first two words are titled, and the center is to discuss how people should know foreign things. The whole article consists of two parts. In the first part, the dialogue between Poseidon and the river god in Beihai is completed in one go, which constitutes the main body of this paper. In the second part, don't write six fables, each of which is self-contained and unrelated. There is no structural connection with the previous dialogue between Poseidon and River God, and it is not very helpful to express the whole theme, which seems a bit detached.