What Is a Preposition?
In English you use prepositions to connect nouns or between nouns and pronouns. Imagine that you encounter two nouns: elephant and book. You can use prepositions in many ways to connect the two nouns to express different ideas:
the book about the elephant
the book by the elephant
the book behind the elephant
the book in front of the elephant
the book near the elephant
the book under the elephant
The italicized words relate two nouns to each other. These relationship words are called prepositions. Prepositions may be defined as any word or group of words that relates a noun or a pronoun to another word in the sentence.
Take a look at the following table for a list of some common prepositions:
Prepositions never travel alone; they’re always with an object. In the earlier examples, the object of each preposition is elephant. Just to get all the annoying terminology over with at once, a prepositional phrase consists of a preposition and an object. The object of a preposition is always a noun or a pronoun, or perhaps one or two of each. (A pronoun is a word that takes the place of a noun, such as him for Eggworthy, it for omelet, and so forth.)
Here’s an example:
In the afternoon the snow pelted Eggworthy on his little bald head.
This sentence has two prepositions: in and on. Afternoon is the object of the preposition in, and head is the object of the preposition on.
Why, you may ask, is the object head and not little or bald? Sigh. Okay, here’s the explanation. You can throw a few other things inside a prepositional phrase — mainly descriptive words. Check out these variations on the plain phrase of the elephant:
of the apologetic elephant
of the always apoplectic elephant
of the antagonizingly argumentative elephant
Despite the different descriptions, each phrase is still basically talking about an elephant. Also, elephant is a noun, and only nouns and pronouns are allowed to be objects of the preposition. So in the Eggworthy sentence, you need to choose the most important word as the object of the preposition. Also, you need to choose a noun, not an adjective. Examine his little bald head (the words, not Eggworthy’s actual head, which is better seen from a distance). Head is clearly the important concept, and head is a noun. Thus head is the object of the preposition.