This document provides definitions for 20 common English idioms and expressions: "Hang in there", "Go the extra mile", "Sold me out", "Blew me away", "Cry wolf", "Couldn't care less", "Comfort food", "Sit on the fence", "Freak out", "Be a catch", "Hit the nail on the head", "Costs an arm and a leg", "Hit the books", "When pigs fly", "You rock", "Miss the boat", "Get it out of your system", "Pull yourself together", "Once in a blue moon", and "Flip the bird". Short explanations are given for the meaning and typical usage of each idiom.