Prepositions in expressions of time

Prepositions in expression of time

1. The preposition in

• months

  in July, in the month of July

  in September, in the month of September

• years

  in 1996, in the year 1996

  in 2012, in the year 2012

• seasons

  in summer

  in the summer, in the summer of '69

• parts of the day

  in the morning

  in the afternoon

  in the evening

• point of time in the future

  in a minute

  in a fortnight 

  in three weeks' time, in three weeks (only when not ambiguous)

• duration (within a maximum period)

  in a minute

  in two weeks

2. The preposition at

• parts of the day

  at (the crack of) dawn

  at night

• time of day

  at 6 (o'clock), at 7 p.m., at 18 hrs (24-hour clock: airports, the military)

  at midday , at noon 

  at midnight

• festive seasons

  at Christmas

  at Easter

• points in time

  at the weekend  (on the weekend, on weekends )

  at the time, at the same time

3. The preposition on

• days

  on Sunday, on Sundays (Sunday: no preposition  journalese)

  on Good Friday

  on my birthday

• dates

  on the 25(th) of December* 

  on December (the) 25(th)* 

• a particular part of a day

  on the morning of September (the) 11(th)* 

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