| At – for times of the day We use at in these expressions: | at half past 7 at midnight at sunset at breakfast time at the moment / at present - at the same time - at weekends - at the age of... at night - at Christmas | 
| On - for days and dates | on the 5th of June on Tuesdays, on Saturday morning on Christmas Day (but at Christmas) | 
| In - for longer  periods of time In + period of time = a time in the future: | in April in 1987 in the winter of 1976 in the 1930s Jack will be back in a week. The train will leave in a few minutes. | 
| No preposition | next last tomorrow yesterday | 
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