Traditional grammars define prepositions as “words that indicate a relation between the noun or pronoun and another word, which may be a verb, an adjective, or another noun or pronoun.” Prepositional phrases consist of a preposition plus a prepositional phrase complement. In addition to seven primary grammatical functions, prepositions and prepositional phrases perform six nominal functions in English grammar. Nominal functions are grammatical functions prototypically performed by nouns, noun phrases, and noun clauses. The six nominal functions of prepositions and prepositional phrases are:
Prepositional phrases of location and time most often perform nominal functions. However, although grammatical possible, prepositions and prepositional phrases infrequently perform nominal functions.
Prepositional Phrases as Subjects
The first nominal function that prepositional phrases perform is the subject. A subject is a word, phrase, or clause that performs the action of or acts upon the verb. For example, the following italicized prepositional phrases function as subjects:
- Behind the machine shed needs mowed.
- Before ten is a bad time to call him.
- Under the freezer is absolutely disgusting!
- Between seven and nine is when employees must arrive.
Prepositional Phrases as Subject Complements
The second nominal function that prepositional phrases perform is the subject complement. A subject complement is a word, phrase, or clause that follows a copular, or linking, verb and describes the subject of a clause. For example, the following italicized prepositional phrases function as subject complements:
- The most magical time of night is after midnight.
- Studying English grammar is out of this world.
- My least favorite part of the workday is during the afternoon.
- A good place to study is in the library.
Prepositional Phrase as Direct Objects
The third nominal function that prepositional phrases perform is the direct object. A direct object is a word, phrase, or clause that follows a transitive verb and answers the question “who?” or “what?” receives the action of the verb. For example, the following italicized prepositional phrases function as direct objects:
- You must clean under the bed.
- His brother is painting along the ceiling.
- My aunt scrubbed behind the freezer.
- Grandma will decorate on top of the roof.
Note that prepositional phrases functioning as direct objects can sometimes also be analyzed as adjunct adverbials. For example, in the first sentence, You must clean under the bed, the prepositional phrase answers the questions both “what must we clean?” and “where must we clean?” Direct objects answer the question “what?” while adjunct adverbials can answer the question “where?” In the case of You must clean under the bed, the prepositional phrase under the bed is either a direct object or an adverbial depending on the particular analysis of the grammarian.
Prepositional Phrases as Object Complements
The fourth nominal function that prepositional phrases perform is the object complement. Object complements are defined as words, phrases, and clauses that directly follow and modify the direct object. For example, the following italicized prepositional phrases function as object complements:
- Students declare the best time of year during the summer.
- The tour guides announced the most dangerous place to swim along the southern shore.
- The reviewer named the most organized classrooms in the English building.
- The Provost named the cleanest restrooms in the education building.
Prepositional Phrases as Indirect Objects
The fifth nominal function that prepositional phrases perform is the indirect object. Indirect objects are defined as words, phrases, and clauses that indicate to or for whom or what the action of a ditransitive verb is performed. For example, the following italicized prepositional phrases function as indirect objects:
- The maid gave inside the refrigerator a thorough scrubbing.
- My mom has given behind the freezer a good scrubbing.
- The decorator is giving inside the closet some serious consideration.
- My brother should give under his bed some thought.
Prepositional Phrases as Prepositional Complements
The sixth nominal function that prepositional phrases perform is the prepositional complement. Prepositional complements are words, phrases, and clauses that directly follow a preposition and complete the meaning of the prepositional phrase. For example, the following italicized prepositional phrases function as prepositional complements:
- My siblings always nose around in my bedroom.
- She mused about under our beds.
- The maid gawked at behind the refrigerator.
- The secret agent is spying on inside the boardroom.
Prepositional phrases most often function as prepositional complements within prepositional verb constructions. However, prepositional phrases functioning as prepositional complements often can also be analyzed as adjunct adverbials similarly to the problem with direct objects and adjunct adverbials.
Although rare, prepositions and prepositional phrases can perform six nominal functions: subject, subject complement, direct object, object complement, indirect object, and prepositional complement.
Brinton, Laurel J. & Donna M. Brinton. 2010. The linguistic structure of Modern English, 2nd edn. Amsterdam: John Benjamins Publishing Company.
Hopper, Paul J. 1999. A short course in grammar. New York: W. W. Norton & Company.
Huddleston, Rodney. 1984. Introduction to the grammar of English. Cambridge: Cambridge University Press.