What Do Prepositions and Prepositional Phrases Do in English Grammar?

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The Function of Prepositions

Prepositions and prepositional phrases perform many functions within sentences. The function of a word is “what the word does.” For example, the function of the adjective pink in the pink rose is to modify or describe the noun rose. What the adjective does then is to describe the noun. Or, the adjective pink functions to describe the color of the rose.

There are ten main functions of prepositions and prepositional phrases.

  1. Head of preposition phrase
  2. Noun phrase modifier
  3. Noun phrase complement
  4. Adjective phrase modifier
  5. Adjective phrase complement
  6. Verb phrase modifier
  7. Verb phrase complement
  8. Adjunct
  9. Adverbial
  10. Particle

These functions are discussed in the following paragraphs.

Heads of Prepositional Phrases

Prepositions first function as the heads of prepositional phrases. The head of a phrase is the defining word type of that phrase. For example, the heads of noun phrases are nouns, and the heads of verb phrases are verbs. Examples of prepositional phrases include in the oven and during the storm. The heads of those prepositional phrases are the prepositions in and during. The functions of the prepositions in and during are therefore the heads of prepositional phrases.

Modifiers of Phrases

Prepositional phrases secondly function as modifiers and complements of noun phrases, adjective phrases, and verb phrases. Words and phrases that function as modifiers modify or define other words and phrases. For example, the prepositional phrase with blonde hair modifies or describes the noun phrase the little girl in the phrase the little girl with blonde hair by describing what color hair the little girl has. Prepositional phrases also function as modifiers of adjective phrases as in on the walls in The paint was green on the walls or near the bathtub as in The floor was wet near the bathtub. Prepositional phrases likewise function as modifiers of verb phrases as in during the wedding in The woman cried during the wedding or after dinner as in The couple danced after dinner.

Complements of Phrases

Words and phrases that function as complements act to complete the meaning of other words and phrases. The main difference between modifiers and complements is that modifiers are optional and can be replaced by any number of other prepositional phrases while complements are often required. For example, the prepositional phrase of books functions as a complement in the sentence Librarians are fond of books. The prepositional phrase of books is a complement because the adjective fond requires a prepositional phrase to complete its meaning. Therefore, one can say Librarians are fond of books but not just *Librarians are fond. Prepositional phrases also function as complements of verb phrases as in on her babysitter as in The woman relies on her babysitter and as complements of noun phrases as in of the book as in He is the writer of the book.

Adjuncts and Adverbials

Prepositional phrases also function as adjuncts and adverbials in sentences. Adjuncts frame an entire sentence and are optional. For example, the prepositional phrase In my opinion in In my opinion, grammar is interesting functions as an adjunct because In my opinion frames the entire sentence grammar is interesting as being my opinion. Adverbials are similar to adjuncts because adverbials also provide additional information about an entire sentence and are optional. Adverbials, however, express information such as time, place, manner, condition, reason, or purpose of an entire sentence. For example, the prepositional phrase in the backyard provides information about the place where the children played in the sentence The children played in the backyard. Adjuncts and adverbials are both optional because their addition and removal does not change the meaning of the main sentence.


Finally, prepositions function as particles in phrasal verbs. Phrasal verbs are verbs that consist of a verb and one or more prepositions. Examples of phrasal verbs include wake up meaning “to awake,” pass out meaning “to faint,” and look up meaning “to consult.” The function of the preposition in a phrasal verb is called a particle. Prepositions functioning as particles are required in phrasal verbs. Prepositions also function as particles in complex quantifiers as in all of and none of.

For more information on the forms and functions of prepositions in English, please refer to the following articles available on Bright Hub:

Printable Downloads

For a printable sheet of some of the most common prepositions in English, please download List of English Prepositions.

For a printable study sheet of the grammatical functions of prepositions and prepositional phrases in English grammar, please download Grammatical Functions of Prepositions and Prepositional Phrases.