PREPOSITIONS OF TIME: IN, ON, AT

PREPOSITIONS OF TIME: IN, ON, AT

We use:

• at for a PRECISE TIME
• in for MONTHS, YEARS, CENTURIES and LONG PERIODS
• on for DAYS and DATES

Examples: 

At 10 o'clock, at noon, at dawn, at Christmas (time), at the moment, at night, at bedtime, etc.

In the morning, in 2015, in March, in the 1980s, in summer, in the past, in the Ice Age, etc.

On Friday, on July 4th, on my birthday, on Mother's Day, on Monday morning, etc.


HOWEVER, we do not use in, on, at when there is words like: last, next, this, every, etc.

Examples: 

Last Friday night, we went to a party.

Next week there will be a new film at the cinema.

This year will be the last year of school.

I visit my grandparents every Sunday.