Secondly, it is necessary to consult a large number of documents to write "the development status and research trends at home and abroad". You can search for documents related to your research direction on websites such as China HowNet, which can be found on general school websites. At the same time, you can go to the library to check if there are any related books. If your English is good, you can search in foreign professional databases, such as Wiley InterScience in the United States. If you have taken a literature retrieval course in university, you can easily retrieve the articles you need.

Finally, read the literature review and briefly describe the development process, latest achievements and research direction of this research object at home and abroad.