Computers do a splendid job of manipulating text, which makes editing a breeze—and plagiarism commonplace.
Ctrl+C Copies your selection to the clipboard. The clipboard acts a temporary repository that allows the user to quickly move or duplicate text, pictures, or even music and video. As a general rule, the clipboard can only contain one item at a time. Ctrl+X "cuts" your selection. It works like Ctrl+C, but deletes the selection after transferring it to the clipboard. Ctrl+V pastes the clipboard's contents into whatever you're editing. This shortcut will only work if you're trying to paste something that's compatible with the app you're using. Try pasting a picture into Windows Notepad for instance, and nothing will happen.
(Also works on Linux. For Mac OS X, however, press the Command key (⌘) instead of Ctrl.)