Unfortunately, if you forget to put quotation marks around the borrowed material, you will commit plagiarism. There are several types of plagiarism, and several rules and guidelines to prevent it from happening, especially in academic papers. One of the ways to avoid it is by making a direct quotation. That means you use the exact words from your source and credit them properly. It also means you need to use quotation marks, otherwise your own words and those of the source will not be distinguished. Only by doing all that will you avoid committing plagiarism.
