In, on, and at are words that talk about time and place. These words are called prepositions. Prepositions can be tricky, so we will start with some simple rules for prepositions of time and place.
Prepositions of time and place go from general to specific.
For example, English speakers will use the preposition in when referring to general time periods like months, years, centuries, eras. So In is used for a period of time:
- She was born in 1955.
- The sewing machine was invented in the 19th Century.
- The story takes place in medieval times.
On is used for shorter periods of time such as a day or date and holidays:
- Why don’t you stop by on Monday?
- We will celebrate her birthday on 14 July.
- Let’s all get together on New Year’s Eve.
When we need to be very specific and use an exact time, we use the preposition at:
- Why don’t you stop by on Monday at one o’clock?
- We will celebrate her birthday at the restaurant.
- Let’s all meet at midnight on New Year’s Eve.
We do not use prepositions with words like last, next, every, and this:
- I will not be there
in next week.
- They come to visit
on every month.
- We visited Budapest
at last Monday.
- I will call you
in this eveningwhen I get home.