Prepositions

Prepositions of time

At, on and in are all used with time expressions.

At is used for points of time.

• I'll see you at 7 a.m.
• The train arrives at midnight.

On is used for days and dates.

• They only work on Mondays.
• My birthday is on March 30.

In is used for other periods of time.

• We went to Canada in the summer.
• I wrote the letters in the morning.
• John arrived in April.

No preposition is used with last, next, yesterday, today or tomorrow.

• I'll see you again next Wednesday.
• Sue came to see me last week.
• What did you do yesterday?
• They're going to the airport tomorrow.