The introduction refers to the opening part of the paper, which undertakes various tasks such as eliciting research questions, determining research direction, expounding research significance, reviewing related research and summarizing research contents. Introduction is an important part of the whole paper, which must be summarized, comprehensive, systematic and reasonable. In the introduction, the author needs to explain the research background and research status, and determine the research direction and purpose by combining personal research experience and academic achievements. In addition, a careful review and analysis of the existing research can better reflect the innovation and importance of the research and provide theoretical and practical basis for the follow-up research.