Relier Pairs COMMON IDIOMS IN ENGLISHVersion en ligne A short list of common idioms in English. par kepa olaizola garcia 1 Break a leg. 2 Piece of cake. 3 Costs an arm and a leg. 4 You can´t judge a book by its cover. 5 Let the cat out of the bag. 6 Sleep on it. 7 Hit the books. 8 Take it easy. 9 Hit the nail on the head. 10 When pigs fly. You shouldn´t decide upon something based just on outward appearances. Something will never happen. Relax Something that is precisely right. Something is very expensive. Something is very easy. Good luck. To study. To disclose a secret that was supposed to be kept. To think.