There are two main reasons for finding that the quoted part is marked in red. First of all, this is due to the function of the paper duplicate checking system. At present, most universities and academic journals have adopted the duplicate checking system to test the originality and academic integrity of papers. These systems detect similar contents in papers by comparing existing literature databases. Because the cited part usually contains the research results of other scholars, these results may also be cited in other studies. Therefore, when the system detects that the quoted part is similar to other documents, it will be marked in red, prompting the author to check and confirm.

Secondly, the reference part is marked in red, which is also related to the author's reference method and reference specification. When writing graduation thesis, students usually refer to the reference specifications provided by tutors or schools, such as APA and MLA. However, in the actual operation process, due to differences in personal understanding or unfamiliarity with reference specifications, some students may have format problems of reference parts, such as lack of necessary reference marks and errors in reference format. These problems will also lead to the quotation being marked in red, misleading the duplicate checking system.

In view of the above problems, first of all, students should carefully understand and master the citation norms when writing papers to ensure that the citation part meets the requirements. Secondly, when writing the citation part, students can appropriately increase their understanding and comments on the cited literature and reduce the similarity with other studies. In addition, schools and tutors should also strengthen the training and guidance of students' reference norms to help students use them correctly and avoid unnecessary red labels.

To sum up, it is a common problem that the cited parts in graduate papers are always marked in red. Only by strengthening the training and guidance of citation norms and improving students' citation level can we reduce the situation that quotations are marked in red and ensure the originality and academic integrity of the paper.