The structural characteristics of this paper: The structural characteristics of this paper are a step-by-step demonstration method. The argumentation method in this paper is quite distinctive. First, compare the river with the sea. When it rises from the river, the two sides can't tell the difference between cattle and horses, and the sea water can't be measured. This shows the relativity of things and the limitations of Hebo's understanding. So the sea is the biggest? The next discussion is that although the sea is extremely vast, it is not absolutely big. The sea is like a pebble between heaven and earth, and Xiao Mu is among the mountains. Next, from the opposite side, from big to small, the four seas are in heaven and earth, and China is in the sea. People and everything are insignificant, and the size of nature is relative. What about society? The role of human beings in human society is still relative. In this way, through layers of argumentation, layers of deepening and thorough argumentation, the main idea of the article is fully expressed.