Quotations and Dialogue

Q. I have a question concerning the use of brackets. In the sentence below, taken from an NPR article, what purpose do the brackets serve? “In almost two years, we find about 31 percent of papers with unreasonable copy[ing] and plagiarism,” she says, shaking her head.

A. The brackets indicate that the writer of the article altered or inserted something in order to make sense of the sentence.