English Teachers Mina and Marilou are back with a new episode to teach you when to use the prepositions in, on and at. Always remember to use ‘in’ for the month and the year; use ‘on’ for the day and the date; and ‘at’ for the time. For example: in 1991 / in June / on Monday / on September 1st / at 3pm / at 12. The also teach you the correct pronunciation for each phrase. Be sure to check out our website exl-english.com for a free trial class.