Plagiarized writing tends to be painfully obvious to your professors and others who read your work. And they often use a very simply way to check for plagiarism:
Faculty members can search the Internet for specific suspicious phrases in a paper. It can be as easy as a Google search.
There are a number of online services that scan papers and examine them for plagiarism (including close paraphrasing).
Faculty will often be more understanding about deadlines than you might expect. It’s better to request an extension or to take a lower grade than to face the consequences of academic dishonesty.