Time: at - We arrived at 5 o'clock. - He arrived to Japan at night. on - They arrived on Saturday. - She was born on 20 June. in - She was born in June. - She was born in 2000. Place: at: Turn left at the cinema. - Their house is at the end of the street. on: I sat on the floor. - You can find the story on page twenty of the book. in: His office is in the building. - The building is in the city centre.

You can look this up online. :) Search for these keywords: "when to use on at in" The natural way of asking the question is, "When do you use on, at and in?" ("When to use...?" is a translation error.)

AT - PRECISE TIME - at 1 o'clock p.m. - POINT - at the corner, at the subway station, at the bus stop - DESTINATION - at the top of the mountain - LOCATION - at the back of the department store - TIME OF THE DAY - at noon, at night - DESIGNATED SPECIFIC - The train is due at 12:15 p.m. - SPECIFIC ADDRESSES - She lives at 55 Boretz Road in Durham. ON - DAYS - on Monday - DATES - on the 1st of July - SURFACE - on the wall, on the table - PUBLIC TRANSPORTATION - on the train - DIRECTIONS - on the left, on the right - FLOORS - on the 1st floor - STREET - on Mapo Street - AVENUES - on the 5th avenue - DESIGNATED DAYS AND DATES - My brother is coming on Monday. We're having a party on the Fourth of July. - DESIGNATED NAMES OF STREETS, AVENUES, ETC - Her house is on Boretz Road. IN - MONTHS - in June - YEARS -in 2008 - CENTURIES - in the 22nd century - LONG PERIODS - in 6 months - ENCLOSED SPACE - in the box, in my pocket - PRIVATE TRANSPORTATION - in a car, in a taxi, in a lift (elevator) - COUNTRIES - in America, in Korea - TIME OF THE DAY - in the morning, in the afternoon, in the evening - NON-SPECIFIC TIMES DURING A DAY, A MONTH, A SEASON OR A YEAR - He started the job in 1971 She likes to jog in the morning. It's too cold in winter to run outside. - NAMES OF LAND AREAS (towns, counties, states, countries, and continents) - She lives in Durham Durham is in Windham County. Windham County is in Connecticut.