We use: • at for a PRECISE TIME • in for MONTHS, YEARS, CENTURIES and LONG PERIODS • on for DAYS and DATES
MONTHS, YEARS, CENTURIES and LONG PERIODS
DAYS and DATES
at 5 o'clock
at 12.30 am
in the summer
on 28 March
on 25 Dec. 2010
in the 1980s
on Christmas Day
in the next century
on Independence Day
on my birthday
at the moment
in the past/future
on New Year's Eve
In informal style we sometimes leave out 'on': I'm looking forward to seeing him Saturday evening.
Plurals are used to talk about repeated actions: In some offices, employees are allowed to wear less formal attire on Fridays, known as Casual Friday or Dress-Down Friday.
American people say on the weekend; British people say at the weekend! What are you going to do on the weekend (AmE) / at the weekend (BE)?
We do not usually use expressions of time at / on / in before next, last, that, this, every, each, all and some. I heard it this morning on the radio. We met every evening before dinner. You can call me any time you like.
We are going to a party on New Year’s Eve. John and Sally often go out in the evening. See you on Monday morning. We always go to town to do some shopping on Saturday. It is the only time we can. The last train goes at midnight so we had better get going.