1. Introduction refers to the beginning of a book or a paper, explaining the main ideas and contents.

2. Any article always has a beginning, and the beginning of a dissertation usually needs a preface (preface, preface, introduction, preface, etc.). The task of the preface is to explain your topic, the main direction of the paper, the process and situation of document retrieval (that is, what the predecessors have done in this regard), what innovations (or arrangements) your paper has, the research methods and papers used. However, many papers have a preface to write, or thank you, or express your feelings, like essays instead of papers. To put forward certain normative requirements for Xu Zhang is to force the author to consider whether he has done literature retrieval or not, and whether the paper has put forward new viewpoints.

3. This part is indispensable in a standardized paper. In general, the content of "Introduction" should at least include the value and significance of the selected topic, literature review, the ideas, materials and methods of this paper, the main contents and logical arrangements of each chapter, etc. Thus, it shows the difference between this study and the existing achievements, emphasizes the uniqueness of this study in materials and methods, and the basic idea of writing the full text, so that readers can better grasp the full text and stimulate their reading interest.