Overview
Prepositions of time indicate when something happens. 'At' is used with specific times (at 3 o'clock), 'on' with days and dates (on Monday), and 'in' with months, years, and longer periods (in January, in 2020). These three are among the most commonly tested in English.
at / in / on
- atat exact times: at 3pm, at midnight, at noon
- inin months, years, seasons: in July, in 2022, in winter
- onon days and dates: on Monday, on 5 March, on Christmas Day
- atat fixed periods: at the weekend, at night, at Christmas
since / for / during / by
- since + point in time: since 2010, since Monday (still ongoing)
- for + duration: for three years, for a week
- during + event/period: during the film, during summer
- by + deadline: by Friday, by noon (= no later than)
Common Mistakes
- ❌ I arrived in Monday → ✅ I arrived on Monday
- ❌ She has lived here since three years → ✅ for three years
- ❌ We met in 5 o'clock → ✅ we met at 5 o'clock
When to use
Appointments
The meeting is on Thursday at 2pm.
Schedules
She starts in January and finishes in June.
Deadlines
Please submit the form by Friday.
Duration
They have been married for twenty years.