In fact, strictly speaking, the line between citation and plagiarism is blurred. Without a clear rule, no one can guarantee that his paper is free from plagiarism and citation. Many people say that there are many papers in the world, but in 99% cases, there is still a difference between repetition and citation in the papers.
For conventional paper writing, the probability of high repetition rate of original papers is very low, but it is not without it. When we write a paper, we learn from previous research results or sentences. Of course, we need to mark it with endnotes, and the cited references need to be displayed at the end of the paper. It turned out to be my own. Don't be afraid of that kind of large-scale repetition. The possibility of finding out plagiarism is still relatively low, but only if there are fewer people writing in the direction of your thesis topic.
If we write papers according to academic standards, there is little possibility of plagiarism. Those who are very concerned about plagiarism and quoting the boundary, if they are not scholars in laws and regulations, or people who are greedy for petty gain near the boundary, for those people, if you quote other people's achievements but are not marked as duplicates, they will think, how many lines does it take?
In fact, in reality, no matter how strict the boundaries are, as long as there are similarities between the two, there is room for development. No matter how clear the boundaries are, for some people, they are just differences in difficulty.