What are the Parts of a Prepositional Phrase?

In simplest terms, prepositional phrases consist of a preposition and an object of a preposition. Prepositions are indeclinable words that introduce the object of a prepositional phrase. Indeclinable words are words that have only one possible form. For example, below is a preposition, but belows or belowing are not possible forms of below.

The noun phrase or pronoun that follows the preposition is called the object of the preposition. For example, behind the couch is a prepositional phrase where behind is the preposition and the noun phrase the couch acts as the object of the preposition. Sometimes adjectives are used to further modify the object of the preposition, as in behind the big old smelly green couch.

Formal Functions of Prepositions

Prepositions perform three formal functions in sentences. They can act as an adjective modifying a noun, as an adverb modifying a verb, or as a nominal when used in conjunction with the verb form to be.

Prepositions Functioning as Adjectives

In the following sentences, prepositional phrases perform the function of modifying the nouns boat, pen, and car:

Look at the boat with the blue sail. Please hand me the pen next to the telephone. Park the car beside the fence.

Prepositions Functioning as Adverbs

In these examples, notice how the prepositional phrases perform adverbial functions by modifying the verbs after, stalled, and won:

The coyote runs after the rabbit. The car stalled despite the tune-up. The team won without the starting quarterback.