In, On, At for Time Exercises

The three main prepositions for time in English are in, on, and at. Use in for longer periods — months ("in March"), years ("in 2024"), seasons ("in summer"), and parts of the day ("in the morning," "in the afternoon," "in the evening"). Use on for specific days and dates — "on Monday," "on 25th December," "on my birthday." Use at for exact times and short moments — "at 9 o'clock," "at noon," "at midnight," "at Christmas," "at the weekend" (British English).

A helpful way to remember is to think about size: in covers the biggest periods (months, years, seasons), on covers medium periods (days, dates), and at covers the smallest, most precise moments (times, holidays). Be careful with fixed expressions that break the pattern: "at night" (not "in the night" as a general rule), and "at Christmas" or "at Easter" (festivals use "at"). When "last," "next," "this," or "every" comes before a time word, drop the preposition entirely: "I went last Monday" (not "on last Monday"). This rule is frequently tested in Cambridge A2 and B1 exams.