slug: prepositions-time-place title: Prepositions of Time & Place group: structures order: 12 summary: Use in, on, and at correctly with times, dates, and locations by matching the preposition to the size or precision of the reference. formula: in/on/at + noun (time or place)
When to use it
The three core prepositions — in, on, and at — follow a simple rule based on specificity: in for large or general containers (months, years, cities), on for medium-sized references (days, dates, surfaces), and at for precise points (exact times, specific addresses).
I was born in June in 1998. The class is on Monday. It starts at 9 a.m.
The same three-level pattern applies to place: in a country or city, on a surface or street, at a specific address or institution.
Form
| Preposition | Time | Place |
|---|---|---|
in | months, seasons, years, centuries, parts of day (in the morning) | countries, cities, rooms, enclosed spaces (in Vietnam, in the kitchen) |
on | days of the week, specific dates (on Monday, on 3 May) | surfaces, streets (on the table, on Lê Lợi Street) |
at | clock times, specific moments (at 8 p.m., at noon, at midnight) | specific addresses, venues, institutions (at 12 Nguyễn Huệ, at school, at the airport) |
Exceptions to memorise: "at night" (not in night); "in the morning / afternoon / evening" but "at night"; "on time" (punctual) vs "in time" (not too late).
Examples
- The conference is in March, on the 15th, and it starts at 10 a.m.
- She studied English at university in Hồ Chí Minh City.
- The book is on the shelf in the living room.
Common mistakes
- Using
infor days: "in Monday" → on Monday. - Using
onfor clock times: "on 7 o'clock" → at 7 o'clock. - Using
infor specific addresses: "She works in 45 Đinh Tiên Hoàng" → She works at 45 Đinh Tiên Hoàng.