Prepositions for Time
Relating "When"
In – On – At
| IN | ON | AT | |||
|---|---|---|---|---|---|
Use in for larger periods of time. |
Use in for smaller periods of time. |
Use at for precise periods of time. |
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MONTH |
in June |
DAY |
on March 1, 2009 |
HOUR |
at noon, midnight |
YEAR |
in 2005 |
WEEK DAY |
on Tuesday |
TIME OF DAY |
at 3:00 a.m. |
DECADE |
in the 1990s |
EXPRESSIONS |
on the dot (exactly on time) |
EXPRESSIONS |
at the end of the day, week, month, year |
CENTURY |
in the 18th century |
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on time |
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at the beginning of the day, week, month |
ERA |
in the pleistocene era |
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EXPRESSIONS |
in a second |
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*Once a year there are two full moons in one month.
In, On, At vs. By
| IN, ON, AT | BY |
|---|---|
A specific time – not earlier or later. |
A time before but not later than this time. |
I had to be there at noon to catch the bus. (exactly) |
I had to be there by noon to catch the bus. (no later) |
We arrived at their house on Wednesday evening. (exactly) |
We arrived at their house by Wednesday evening. (no later) |
He reached Istanbul in June, 1906. (exactly) |
He reached Istanbul by June, 1906. (no later) |
On time vs. I n time
| ON TIME | IN TIME |
|---|---|
A specific time, no later. |
An acceptable time that still permits doing the activity. |
Please get here on time for your meeting. |
Please get here in time to see him before he leaves. |
The plane departed on time. |
We arrived just in time to catch the plane. (We were last to get on.) |
We arrived on time to see the movie. (We saw the movie and the Previews.) |
We were arrived in time to see the movie. (We saw the movie, but missed the Previews.) |
Practice
Travel
- Select the word from each menu that best completes the sentence.
- Compare your response to the answer by clicking the "check" button to the right.



