10 Idiomatic Expressions and Sentences1. Break the ice – to start a conversation in a friendly waySentence: To break the ice during our first day of class, the teacher asked us to share fun facts about ourselves.2. Hit the nail on the head – to be exactly right about somethingSentence: When Anna said we failed the project because of poor planning, she hit the nail on the head.3. Piece of cake – something very easySentence: The qúiz was a piece of cake because I studied all night.4. Under the weather – feeling sickSentence: I didn’t go to school today because I was feeling under the weather.5. Cost an arm and a leg – very expensiveSentence: That designer bag costs an arm and a leg, so I’ll just stick to my budget.6. Let the cat out of the bag – reveal a secretSentence: Mark accidentally let the cat out of the bag about our surprise party for Carla.7. Bite the bullet – to do something painful or unpleasant that cannot be avoidedSentence: I had to bite the bullet and confess to my parents that I broke the window.8. Burn the midnight oil – to work late into the nightSentence: I burned the midnight oil just to finish our group project before the deadline.9. In hot water – in troubleSentence: She’s in hot water for copying her classmate’s homework.10. Once in a blue moon – very rarelySentence: My cousins from the province only visit us once in a blue moon.