It is a short paragraph written in front of the text, which serves as an outline. The first paragraph of this composition is a preface. Generally, the preface is not listed as a title, but a paragraph leads to the text. Don't use too many words, usually about 500 words. However, foreign journals introduce the research background knowledge for a long time. The preface is to give readers some preparatory knowledge, thus arousing their interest in reading. Therefore, we should pay special attention to conciseness, get to the point, be fascinating and avoid tedious review of research history. In the preface of the research paper, the historical materials closely related to this paper are briefly introduced. ?

The preface mainly explains the source of the research question and the writing purpose of this paper. The source of the subject can come from literature or clinic, which needs to be clearly written in the preface. What is the problem to be studied and where does it come from? What problem does this article want to solve? Sometimes a scientific research work has been going on for many years. This paper is a summary of the previous work. It is necessary to explain the general purpose of this scientific research work. Previously published papers have solved one of the problems, and this paper will solve one of them. In short, the purpose of the paper should be clearly written, so that readers can see at a glance the source, importance and purpose of this study. The content of the preface need not be repeated in the text, and the first author often repeats the preface and discussion, which is not allowed. ?

In short, the preface is to describe the research background and trend, research purpose (including ideas), scope, history, significance, methods and important research results and conclusions in simple words. The preface should be relevant, play a role in preparing the reader's knowledge and be fascinating.

Preface, also called preface, preface, narration, thread, quotation and ballad, is written in front of a book or article and usually describes the author's writing psychology, process, thoughts and experiences. In this paper, the preface is called "Introduction", which introduces the writing background and purpose of this paper in a short space, describes the author's psychology or general understanding of this article, and also points out the theoretical basis, experimental basis and research methods of this article. In books, the preface is called "preface", which is usually used to explain the author's creative intention and writing process. It is also written by others and is often used to introduce and comment on the contents of the book.