How do you use the prepositions ‘in’, ‘at’ and ‘on’ correctly?
How do you use the prepositions in, at and on correctly?
These 3 prepositions are easily confused because they are all used to denote locations of an object.
So how do you use them correctly? For example, how do you know when to use in the box, on the box, and at the box?
These 3 prepositions can be used in 2 very different kinds of situations. They are be used to describe the location of an object, or be used to denote specificity so that they can describe more abstract objects, like time.
Let’s start with how they are used in describing the location of an object. The preposition in is usually used to describe the state of being inside an object. The preposition on describes the state of being on the surface of an object. Lastly, the preposition at describes the state of being at a point of an object.
Let’s look at a few examples.
The sentence, “The cat is in the box”, tells us that the subject cat is inside the box.
The sentence, “The cat is on the box”, tells us that the subject cat is on the surface of the box.
Lastly, the sentence, “The cat is at the box”, tells us that the subject cat is at a specific location of the box.
Denoting locations using these preposition are mostly used when physical objects are involved.
But how about abstract objects like time? Do you used in Monday, on Monday, or at Monday? (On Monday is correct.)
This is where specificity comes in. The preposition in is the least specific, at is the most specific, and on is in the middle of the two.
Hence the preposition in pairs up with the least specific time, like in ten years, in a decade, in a day, in the afternoon, in 1999. You don’t exactly know a specific date, but you do know what the time is in general. Although a numbered year (e.g. 1999) seems specific enough, it is sufficiently ‘vague’ because it refers to a numbered year rather than a particular month or day, which is much closer to an exact date.
The preposition on pairs up with a more specific time, like on Monday, on December, or on 21st June. A particular day or a month (e.g. on Monday or on December) is much more specific than simply stating “day” or “month” (e.g. in a day), so the preposition on is used instead. And an exact date is more specific too, and on pairs with it (e.g. on 21st June).
Finally, the preposition at pairs up with the most specific representation of time, like at 4 P.M., at noon, or at this moment. As you can see, at is paired up with a particular moment in time. And it is also used when you want to specify the present moment (e.g. at present, or at this moment).
There are exceptions, however. For example, even though the preposition in is used to denote a non-specific part of a day (e.g. in the morning, in the afternoon, or in the evening), the preposition at is used to pair with night, as in at night.
So now you know how to use these 3 prepositions correctly (in most cases)!
When these prepositions are used with physical objects, in refers to the state of being inside an object, on refers to the state of being on the surface of an object, and at refers to the state of being at a point of an object.
When these prepositions are used with non-physical, abstract objects, in is the least specific, on is more specific, and at is the most specific.
And like most grammar rules, there are exceptions to these rules.