Prepositional phrases modify nouns and verbs while indicating various relationships between subjects and verbs. They are used to color and inform sentences in powerful ways.
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 subject 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 subject of the preposition. Sometimes adjectives are used to further modify the subject of the preposition, as in behind the big old smelly green couch.
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.
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.
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.
In English, sometimes words function as nouns but aren't themselves nouns. These words are called nominals. Prepositions sometimes perform this important function in sentences when they are used in conjunction with the verb to be. For example:
The park is next to the hospital. The student is between an A and a B. The fight scene is before the second act.
In semantic terms, the preposition functions to illustrate a logical, temporal, or spatial relationship between the object of the prepositional phrase and the other components of the sentence. Consider the following examples:
The dog is asleep on his bed.
In this example, the prepositional phrase on his bed indicates a spatial relationship between the subject dog and the object bed. If the preposition on was replaced with under or beneath the spatial relationship would be altered.
The town hasn't been the same since the war.
In this sentence, the prepositional phrase since the war indicates a temporal relationship between the verb phrase hasn't been the same and the object war.
The family survived despite the accident.
he prepositional phrase despite the accident in this sentence indicates a logical relationship between the survival of the family and the accident.
The following chart lists the most commonly used prepositions in English:
There are no rules that govern how much nouns and verbs can be modified in English. Often writers employ prepositional phrases excessively, creating an almost comical effect in an attempt at over clarification. The following sentence implements a string of propositional phrases to modify the verb stood.
The old farmhouse stood for years, after the revolution, by the fork in the road, beyond the orange grove, over the wooden bridge, at the farthest edge of the family's land, toward the great basin, down in the valley, under the old mining town, outside the city's limits, and past the end of the county maintained road.
Prepositional phrases, in theory, can modify sentences infinitely. Therefore, it is important for writers to understand their form and function in order to make appropriate stylistic choices.