Prepositions are funny beasties. They're not nouns, verbs, or pronouns, but they add context and nuance to your sentences. They can be as short as a two-letter word, or you can get quite lengthy with a prepositional phrase. But don't get too hung up on the exact grammar theory; they're quite easy to use. We're going to clear everything up and have you purposefully prepositioning in no time.
Principles of Prepositions
The secret to understanding prepositions is in the word itself. Preposition: They indicate the position of something or someone, relative to something else.
Examples of prepositions include: in, on, above, underneath, through, across, with, near, between.
Interestingly, prepositions are known as a “closed” word class. Unlike nouns and verbs, no new ones will be added over time.
Using Prepositional Phrases
You can have the individual preposition (those position words we gave above), but these will be used in relation to something else. This combo of words is called a "prepositional phrase."
Every phrase with a preposition in it is known as a prepositional phrase. These only need to contain a preposition and a noun/pronoun (which is then known as the object of the preposition).
Examples (the prepositions are bolded in the phrase):
in Paris
above the law
under pressure
These prepositional phrases don't include a subject or a verb, so they aren't complete sentences. But when you have a subject, verb, and a prepositional phrase, you're adding more context to a sentence.
Examples:
The dog was lost in Paris.
He felt above the law.
She thrives under pressure.
In these examples, the objects of the prepositions (Paris, the law, pressure) are linked to the subjects and verbs through the bolded prepositions.
But What Is a Preposition?
A preposition is its own part of speech, but, to make things a little more confusing, sometimes it's an adjective, and sometimes it's an adverb.
This is clearer with some examples:
The lollipop in the jar is for Barry.
Here, the prepositional phrase "in the jar" is describing a noun, the lollipop. It is therefore acting as an adjective.
This can be demonstrated by replacing the phrase with an actual adjective:
The red lollipop is for Barry.
As you can see, "red" plays the same role as "in the jar." It describes the lollipop.
But when the prepositional phrase is describing a verb, it becomes an adverb.
The nun breakdanced across the room.
In this sentence, the prepositional phrase follows a verb, "breakdanced." It is therefore acting as an adverb, as it describes how the nun breakdanced.
The nun breakdanced vigorously.
Since you can replace the preposition with an adverb, you know it serves the same role.
Go forth, and use prepositions with confidence! (What's the preposition in that sentence?)