Ctrl-X - Cut selected text.
Ctrl-C - Copy selected text.
Ctrl-V - Paste copied/cut text.
Ctrl-B - Make selected text bold.
Ctrl-I - Make selected text italic.
Ctrl-U - Underline selected text.
Shift-Enter - Make a line break (instead of a new paragraph, which is created when you press Enter) (Windows)
Ctrl+Return - The same as above, but for Mac.
Esc - close article editor.