Matching Pairs LanguageOnline version Idioms by Fernando T. 1 Cost an arm and a leg 2 A couch potato 3 I am under the weather 4 My blood is boiling 5 Butterflies in my stomach 6 It’s raining cats and dogs 7 A piece of cake 8 Hit the sack 9 In hot water Go to sleep! Very expensive A person who doesn’t have an active life I am very angry! I am sick! Something that you say when it is raining heavily To be in difficulties Very easy! Nervous and anxious