at

on

in

- time: at 7 o’clock

- holidays: at Easter, at Christmas

- in the expressions: at noon, at the weekend, at night

- days: on Monday, on New Year’s Day

- dates: on 2^nd August

- part of a particular day: on Friday night

- months: in January

- seasons: in the spring/ summer/ winter/ autumn

- in the expressions: in the morning/ afternoon/ evening, in an hour, in a minute, in a week/ month/ year/ few days