Break the ice - to initiate conversation or social interaction in a situation where there is tension or awkwardness.Hit the nail on the head - to describe exactly what is causing a situation or problem.Cost an arm and a leg - to be very expensive.Bite the bullet - to endure a painful or difficult situation with courage and determination.Piece of cake - something that is very easy to do.Under the weather - feeling ill or unwell.Jump on the bandwagon - to join or support something that has become popular or fashionable.Let the cat out of the bag - to reveal a secret or confidential information.Kill two birds with one stone - to accomplish two tasks with a single action.A dime a dozen - something common and easily acquired, usually with little value.