The main purpose of this article is to write about some of the happy or unhappy, interesting or contradictory little things in the past three years when I was studying in Polytechnic. Because this article started late, I am already in the second semester of my second year of high school. To recall the events of my first year of high school, I may need to think carefully about the details, so I decided to start writing from the present. I will slowly recall the past things bit by bit. Please forgive me for the chronological order of the article.