It is purely for entertainment, because after reading the article for a long time, I was moved, because suddenly my brain was not clear, because, anyway, I suddenly thought of writing a long article. Long articles are not my specialty, and the writing style is only average. Moreover, I especially don't like to read the introduction at the beginning of the article. After reading the introduction, I guessed about the article, and I no longer have any interest in reading further, so there is no introduction in this article. ——, Can also be regarded as one of my bad habits.