İn-At-On

at
in
on
PRECISE TIME
MONTHS, YEARS, CENTURIES and LONG PERIODS
DAYS and DATES
at 3 o'clock
in May
on Sunday
at 1030am
in summer
on Tuesdays
at noon
in the summer
on 6 March
at dinnertime
in 1990
on 25 Dec 2010
at bedtime
in the 1990s
on Christmas Day
at sunrise
in the next century
on Independence Day
at sunset
in the Ice Age
on my birthday
at the moment
in the past/future
on New Year's Eve

Look at these examples:

• <LI class=MsoNormal>I have a meeting at 9am <LI class=MsoNormal>The shop closes at midnight <LI class=MsoNormal>Jane went home at lunchtime <LI class=MsoNormal>In England, it often snows in December <LI class=MsoNormal>Do you think we will go to Jupiter in the future? <LI class=MsoNormal>There should be a lot of progress in the next century <LI class=MsoNormal>Do you work on Mondays? <LI class=MsoNormal>Her birthday is on 20 November
• Where will you be on New Year's Day?

Notice the use of the preposition of time at in the following standard expressions:

Expression

Example

at night
The stars shine at night
at the weekend
I don't usually work at the weekend
at Christmas/Easter
I stay with my family at Christmas
at the same time
We finished the test at the same time
at present
He's not home at present Try later

Notice the use of the prepositions of time in and on in these common expressions:

in
on
in the morning
on Tuesday morning
in the mornings
on Saturday mornings
in the afternoon(s)
on Sunday afternoons
in the evening(s)
on Monday evening

When we say last, next, every, this we do not also use at, in, on

• <LI class=MsoNormal>I went to London last June (not in last June) <LI class=MsoNormal>He's coming back next Tuesday (not on next Tuesday) <LI class=MsoNormal>I go home every Easter (not at every Easter)
• We'll call you this evening (not in this evening)