For example:

Brown (1983: 23 1) thinks that communicative approach is a more effective method in English teaching. (There is the author's name in the quotation, and the information in brackets is the year and page number. Page number information can be omitted here)

2) Quoting Bert (1977), Milroy (1980: 135) pointed out that ... (Another author was quoted in the indirect speech).

3) The previous report (Blake, 1977) indicated the importance of this prior knowledge. (The author's name does not appear in the quotation, so it should be given in brackets. )

4) Some researchers have confirmed the limitations of this method (Koo,1985; Manson,1961; Watkins, 1979) (if you need to quote more than one author, but use this format)

Extended data:

With the rapid development of computer technology and Internet, online query, retrieval and download of professional data has become an important means of scientific and technological information retrieval. For all kinds of full-text databases or abstract databases on the Internet, abstract index is an important tool for readers to retrieve documents, which provides convenience for the construction and maintenance of scientific and technological information literature retrieval databases.

It is a comprehensive introduction to the paper, so that people can understand the main contents of the paper. After the paper is published, the abstract can be directly used by abstract magazines or various databases without modification or slight modification, so that readers can know the main contents of the paper as soon as possible to supplement the deficiency of the title, thus avoiding misunderstandings, deficiencies and even mistakes that may occur when others compile the abstract. Therefore, the quality of abstracts directly affects the retrieval rate and citation frequency of papers.

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