English Prepositions of Time

This unit covers prepositions of time such as at, on, and in. These prepositions are used frequently in time expressions. For example: “at 5 o’clock,” “on Saturday,” and “in one week.” There are many prepositions of time in the English language. At, in, and on are three common ones, and they have particular uses.

At
– at 4 o’clock / 4 pm, at sunset, at night, at noon

In
– in July, in the afternoon, in the spring, in the 20th century, in 2020

On
– on Monday, on Thanksgiving, on the weekend, on Saturday nights

These expressions omit at, in, and on whenever the words “next” or “last” are used. For example: next Tuesday, last weekend, next summer, last year.

Another exception to keep in mind is “tomorrow” and “yesterday” – neither uses at, in, or on.

Other prepositions of time include: after, before, by, during, for, from…to, from…until/till, and in.

Examples:
After the concert, we will get something to eat.
You should rest before the race.
The project must be completed by Friday afternoon.
We were silent during the speech.
Pam can talk about physics for hours.
The baby usually takes naps from 1 to 3 pm. 
From the time he gets up until (the time) he goes to bed, Frank is very busy.
The train leaves in 10 minutes.