Preposition of Time
A number of prepositions may be used to denote time such as on Monday, before night, during the night, till tomorrow, after lunch, etc. In most cases, it is easy to know which preposition to use.
Uses of Preposition of Time
At, on, in
(A) At usually denotes a definite point of time but can also be used for definite periods:
Definite points of time
at 3 o'clock, at midnight
at the beginning of the class
at the end of the meeting
Indefinite periods of time
at dawn, at night
at Christmas, at Diwali
(B) On is used with days and dates:
On Monday, on 10th August
On the Diwali day, on Christmas eve
On the evening of the 8th April
(C) In
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