Before you click Begin Quiz, first set the number of words to drill on, up to 234. You must select at least 30 to get extra credit!   Remember for DOS/Windows machines, you click the tab key to check your answer, then any other letter key to get next word, or use the Continue button if that does not work.  On Macs you can use the tab key both times.  DO NOT USE THE ENTER KEY!! IF  THE PROGRAM BEGINS TO MALFUNCTION SERIOUSLY,  CLOSE THE WINDOW AND RELOAD THE PAGE.