Narrative preface. This is the most common way to write a preface, that is, to make your thoughts clear in concise and general language.

The preface of the quotation. It refers to expressing one's central idea by quoting literature, ancient poetry and ancient prose, with the purpose of embodying the literariness of the paper and expressing the preface of professional academic questions. It refers to expressing your thoughts by setting questions. This way can stimulate readers' interest in reading.

The writing of the preface is not limited to one writing method, and two different writing methods can be combined as needed, so that the preface written will be better and the information of the paper will be clearer.

From general aspects to special topics, clear up the background knowledge of the research topic at one time. Explain what problems have been solved by previous research. Explain what unknown problems still exist in previous research. The basis and importance of studying the problem: explain the problem, hypothesis or purpose to be studied. Explain why we should do this research and emphasize the necessity of this research.

After introducing the significance of research background, research basis and research purpose, the preface is basically completed, and then there should be a summary paragraph to guide readers to naturally transition from the previous speech to the next part of SCI paper, that is, the material and method part. The summary paragraph is usually to briefly explain your research design, the methods used to achieve the research purpose, and finally summarize the main results.