Prepositions of time
The preposition we use when we talk about a period of time depends on how long the period of time is.
Specific day
| on | 18th May Christmas Day my birthday |
Short period (longer than 1 day less than 1 month)
| at | the weekend Christmas ( the Christmas period not just Christmas day) |
Long period (at least a month)
| in | June summer 1990 the 1960s the 16th century |
Time
| at | 7 o’clock midnight |
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