1. Piece of cake – Very easy.
2. Costs an arm and a leg – Very expensive
3. Break a leg – good luck!
4. Hit the books – go and study
5. Let the cat out of the bag – to expose a secret .
6. Hit the nail on the head – doing or saying something that is precisely right.
7. When pigs fly – something will never happen.
8. You can’t judge a book by its cover – never judge appearances.
9. Bite off more than you can chew – to attempt to take on a task that is too much for you to handle.
10. Scratch someone’s back – to help someone out with the assumption that they will return the favor in the future!
11. It's raining cats and dogs – when it rains heavily
Dear readers , the list of course is not exhaustive , you can suggest other idioms . Let's make the list as long as possible .