The main body of the paper includes three parts: preface, theory and conclusion. The words "introduction", "discussion" and "conclusion" do not appear in the general text, but there should be an introduction paragraph and a conclusion paragraph. Text theory is the main body of the paper, which is generally divided into several parts and several discussion levels. Subtitles or numerical numbers are required to show the clear ideas of the article. The text is the main body of the paper, which should include the argumentation process and conclusion.