The words IN, AT, and ON are a part of speech called prepositions.
Prepositions express TIME or LOCATION for people, places, and things.
The front page photo to this article shows a variety of uses of IN, AT, and ON. After reading this, you should be able to identify certain phrases like “at home,” “in the kitchen,” “on the phone.”
Following are some basic examples and guidelines.
TIME: in a week; at 6 o’clock; on Thursday.
IN shows how much time until something.
AT specifies the time of day.
ON tells what day.
If you say, “The meeting is in a week, on Thursday at 3 pm,” each preposition is used to express the idea of time, from general to more specific.
LOCATION: in a restaurant; at the airport; on the computer
IN is used with places that are contained spaces, or that have borders or geographic limits
AT is used with general location
ON is used to show location on a flat surface (on the wall, on the floor, on the street)
If you say, “Sheila is at the airport in a restaurant and on the computer,” you express Sheila’s general location (at the airport), more specific location (in a restaurant) and the exact focus of her attention (on the flat screen of her computer).
Many languages use prepositions – but every language uses them differently. So, please don’t apply your native language usage to English. Instead, try to learn them in context. For example, the Desperate Housewives live ON Wisteria Lane. Each housewife lives IN a home, etc.
Another way is from songs: “The rain in Spain stays mainly on the plain” (“My Fair Lady”) or from movies or books: “We don’t discuss business at the table” (“The Godfather”).
For practice, take another look at the front page photo and see if you can find some more sample phrases using IN, AT, and ON.