Uses:
1. “On” is used with “dates” and “days”
Examples:
– He was born on 14 th April, 2002. (date)
– On Friday (day)
2. “In” is used with “periods of time”
Examples:
– In two weeks.
– In April.
– In the summer.
– In the afternoon.
3. “At” is used with “a precise time”
Examples:
– At 10.30 a.m.
– At 4.25 p.m.
Notes:
There are some exceptional cases such as:
Warning:
With some time expressions no preposition is used.
Examples:
– I received their final answer in last week.
– We had some guests on yesterday!