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You may hear, “I went to work on Monday,” or “Let’s have a picnic on Memorial Day.” For the most specific times, and for holidays without the word “day,” we use at . That means you will hear, “Meet me at midnight,” or “The flowers are in bloom at Easter time.” Everyday Grammar - Prepositions of time Prepositions and Place When English speakers refer to a place, we use in for the largest or most general places.