LEARN · PART 5

Prepositions of Time on TOEIC

TOEIC routinely tests the choice between 'at', 'on', 'in', 'by', 'until', 'during', and 'for' in time expressions. The rules are simple but the test takers most often miss them when the time expression is embedded in a longer business-context sentence.

Rules

'At' is used for specific clock times and short fixed times: at 3 PM, at noon, at midnight, at the moment.
'On' is used for days and dates: on Monday, on April 5, on weekends, on my birthday.
'In' is used for longer periods: in 2026, in July, in the morning, in the 21st century.
'By' means 'no later than': 'Please submit your report by Friday' means Friday or earlier.
'Until' means 'continuing up to a point': 'The office is closed until Monday' means Monday is the first open day.
'During' refers to a period in which something happens: 'during the meeting', 'during the renovation'.
'For' refers to a duration: 'for three years', 'for two hours'. Contrast with 'since' (specific start time).

Examples

"The conference begins at 9 AM on March 15, in the main hall."

Three prepositions of time in one sentence — at (clock time), on (date), in (location, but the same logic). All three are required and not interchangeable.

"Please submit your expense reports by the end of the month."

'By' is the deadline preposition. 'Until the end of the month' would mean the user must keep submitting reports continuously — a different meaning.

"The renovation will continue for three weeks during the holiday season."

'For' indicates duration of an activity; 'during' indicates the period when it happens. The two are often confused, but both are required for natural English.

What TOEIC specifically tests

'By' versus 'until' is the most-tested preposition distinction on TOEIC. 'By Friday' means a deadline; 'until Friday' means a continuing state. The error pattern is symmetric in both directions.
'During' versus 'for' is tested in Part 5 with a long time noun. 'During the meeting' (a fixed event) versus 'for three hours' (a duration) — they describe different aspects of time.
'In' versus 'on' when the time expression is a month with a date. 'In March' is correct; 'on March 15' is correct; 'in March 15' is wrong. The article only kicks in with the specific date.

Common questions

What's the difference between 'by' and 'until' on TOEIC?

'By' means 'no later than' and refers to a deadline; 'until' means 'continuing up to a point'. 'Submit the report by Friday' means Friday is the deadline. 'The office is closed until Friday' means Friday is the first day it reopens. TOEIC Part 5 frequently tests this distinction.

When do I use 'at', 'on', or 'in' for time?

'At' is used for specific clock times (at 3 PM, at noon). 'On' is used for days and dates (on Monday, on April 5). 'In' is used for longer periods (in 2026, in July, in the morning). The three are not interchangeable, and TOEIC Part 5 distractors include the wrong choice as a plausible-looking option.

Is 'during' followed by a noun or a clause?

'During' is followed by a noun phrase, not a clause. 'During the meeting' is correct; 'during we met' is wrong. The corresponding conjunction for a clause is 'while': 'while we were meeting'. TOEIC tests this in Part 6.

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