The main differences between preface and abstract are their functions, characteristics and types.

Introduction, the main task is to make a general plan for the basic content and outline of the whole paper. Usually, it includes all or several of the following five items:

Introduce the background, significance, development and current level of a research field; Review and summarize the literature in related fields, including previous research results and solved problems, and make appropriate evaluation or comparison;

The task of the introduction is to explain the 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) their own papers have, the research methods adopted, the general structure of the paper and other issues that need to be explained.

It is a summary of the essence of the full text, a summary of a scientific research work or technical practice, which can be summarized from the aspects of purpose, method and research results. Generally speaking, before the main part, it is mainly to let readers know the content of the paper first.

The main purpose of the introduction (the first layer) is to tell readers what the research field and significance are, what problems the research should solve, and what the current situation or level is.

Literature review is an important part of academic papers, and it is the author's summary and comments on the work and research results of others in a certain research field, including his representative views or theories, inventions and discoveries, and methods to solve problems. When quoting other people's research results, you should indicate the source, that is, who, when and where publicly published this research result.