Prepositional Phrases in English Grammar

In English grammar, a prepositional phrase is a group of words made up of a preposition (such as to, with, or across), its object (a noun or pronoun), and any of the object's modifiers (an article and/or an adjective). It is only a portion of a sentence and cannot stand on its own as a complete thought. Prepositional phrases often tell where something happened, when it happened, or help define a specific person or thing. Because of these functions, they're often essential to understanding a sentence.

Types of Prepositional Phrases

Prepositional phrases can modify nouns, verbs, phrases, and complete clauses. Prepositional phrases can also be embedded inside other prepositional phrases.

Modifying Nouns: Adjectival Phrases

When a phrase modifies a noun or pronoun, it's called an adjectival phrase. These types of phrases often specify a person or thing (what kind, whose). In context, they clarify a distinction between several possibilities. For example:

• Sheila is the runner with the fastest time.

It's likely there are other runners who are slower, as the sentence is specifying who is the fastest. The phrase is modifying (describing) the noun runner. Adjectival phrases come directly after the noun they modify.

• The boy with the tall woman is her son.

The phrase with the tall woman is specifying a certain boy; it's an adjectival phrase. There could be other boys, but the one with the tall woman is the one that's being described. The boy is a noun phrase, so the prepositional phrase is an adjective. If we want to make the boy even more specific, we'd further qualify it with an embedded phrase.

• The boy with the tall woman and the dog is her son.

Presumably, there are multiple boys with tall women, so the sentence is specifying that this boy is with a tall woman who has a dog.

Modifying Verbs: Adverbial Phrases

Adverbs modify verbs, and sometimes the adverb is an entire adverbial phrase. These phrases often describe when, where, why, how, or two what extent something happened.

• This course is the most difficult in the state.

The prepositional phrase specifies where. There might be other courses that are more difficult in other states, but this one is the most difficult here. Let's say it's just one difficult course of several in the state, i.e., "This course is among the most difficult in the state." The among phrase is an adjectival phrase modifying (describing) the course, and the final phrase remains adverbial, still telling where.

• She ran the marathon with pride on Saturday.

The first prepositional phrase specifies how she ran (a verb), and the second specifies when. Both are adverbial phrases.

List of Prepositions

Here are some of the most commonly used prepositions in English. Be aware that just because a word in a sentence is on this list doesn't mean that it's being used as a preposition in any particular context. Many of these words can also be other parts of speech, such as adverbs or subordinating conjunctions.

Preposition, Conjunction, or Adverb?

To tell if a word is a preposition, look to see if it has an object. If there's a clause following it, you're likely dealing with a conjunction. If it's at the end of a clause instead of the beginning (or the end of a sentence), it's likely an adverb.

After

• In the following example, there is no object following after, and the word introduces a clause, so it's clear that after is a conjunction: After we ate, we went to the theater.
• In the following example, there is an object following after, which means it is used as a preposition: After lunch, we went to the game.

Before

• In the following example, there is an object following before, which means it is used as a preposition: You've put the cart before the horse.
• In the following example, there is no object following before; it is being used as an adverb: I've heard that somewhere before.
• In the following example, there is no object following before and the word introduces a clause, so it's clear that before is a conjunction: Come over before you leave.

Out

• In the following example, there is an object following out, which means it is used as a preposition: The cat followed the child out the door.
• In the following example, there is no object following out; it is being used as an adverb: Would you like to go out for lunch?

When these words are part of a verb phrase, they're adverbs. You check out, look up, and call off something, so these words might appear to be prepositions with objects. But they can't be split off from their verbs.

• He checked out the book.

Out the book is not a prepositional phrase, as you don't go out a book.

Examining Your Writing

If your writing often contains very long sentences, consider using prepositional phrases as a tool for reorganizing your work when revising. Too many prepositional phrases, however, can make a sentence difficult to understand. This issue can often be fixed by splitting a long sentence into two or three shorter sentences or moving the verb closer to its subject.