Choose the appropriate preposition for the blank : 'I shall come back ____ 7 O'clock.'

Question

Accepted Answer

The correct option is 3:
The correct preposition to use when referring to a specific, precise point in time, such as an hour on a clock, is "at." In English grammar, "at" is used for clock times ('at 7 o'clock,' 'at midnight'), holidays ('at Christmas'), and specific points in time ('at the moment'). The sentence "I shall come back at 7 O'clock" correctly indicates the exact time of return, making "at" the only grammatically and contextually appropriate choice for this specific time reference. This rule is fundamental to using prepositions of time accurately.

The incorrect option is 1:
The preposition "in" is generally used for longer, non-specific periods of time, such as months ('in July'), years ('in 2024'), seasons ('in winter'), or general parts of the day ('in the morning'). It can also refer to a duration or the end of a future period ('in ten minutes'). It is not used to denote a precise clock time like '7 O'clock.'

The incorrect option is 2:
The preposition "to" is typically used to express movement toward a place or person ('go to the store') or to indicate a range of time ('from Monday to Friday'). While "to" can sometimes be used in time expressions (e.g., 'twenty minutes to seven'), it is never used in the context of specifying a single, exact time of arrival or return after the verb phrase "come back."

The incorrect option is 4:
The preposition "for" is used to indicate duration ('for two hours') or purpose ('a gift for you'). It is incorrect in this sentence because '7 O'clock' is a specific time, not a duration of time, and using "for" would incorrectly imply that the speaker is coming back for the duration of 7 O'clock, which makes no sense in standard English usage.