Open the brackets to know what happened to Robert.
Robert always (to leave) his keys in the hall but yesterday he (can, cannon) see them anywhere. Robert didn't (to lock) the door and (to leave) the house. He (to meet) John in the street and (to join) him. He told John about the keys. John (to laugh) a lot and then he (to shout), "Look! Your keys are in your pocket."