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