a. Time flies - The perception that time passes quickly. Example: "It feels like yesterday when we started college; time flies." b. Race against time - To hurry or work quickly to meet a deadline. Example: "We're in a race against time to finish the project before the end of the day." c. Kill time - To occupy or pass the time in an enjoyable or unproductive way. Example: "I usually read a book to kill time during my commute." d. In the nick of time - Just in time, at the last possible moment. Example: "He arrived in the nick of time to catch his flight." e. Once in a blue moon - Very rarely or infrequently. Example: "We only see each other once in a blue moon since she moved abroad."