In the process of writing a thesis slowly, I found that the process of writing a thesis is actually the process of seeing the essence of a problem clearly. Because you want to find the right line in a strict logical system, and then straighten out the cause and effect, you have to find the logic to solve the problem. Being able to write a paper shows that you have a deep understanding of this problem. The teacher has written so many papers and clarified the essence of so many problems, so he has formed a thinking logic that can see the essence, so he can see the essence of many things in his eyes. This is the depth of thinking.