Prepositional phrases are groups of words beginning with a preposition and ending with an object of the preposition. Object of the preposition is just a fancy name for the noun or pronoun that follows the preposition.
David pointed at Kyle's bowling ball.
At Kyle's bowling ball is a prepositional phrase. It starts with the preposition at and ends with the noun ball. Here are a couple more examples.
The phrases above both begin with prepositions (near and for) and end with nouns (hotels and Isaac).
They must have a preposition and an object of the preposition, and they may also have other words in them. They might have adjectives that describe the object of the preposition.
near fancy hotels
at Kyle's bowling ball
across the large bedroom
They may also have adverbs that modify the adjectives.
near extremely fancy hotels
across the rather large bedroom
Prepositional Phrases Act As Single Parts of Speech
This seems sort of funny, but all of the words in a prepositional phrase come together to act as one part of speech. Each word within the phrase has its own job, but the words also work together to perform one job. Isn't that interesting?
Prepositional phrases usually function as adjectives and adverbs. Let's check out some examples! I'll even throw in some sentence diagrams to help you understand this better.
The cake with nuts fell onto the floor.
With nuts is a prepositional phrase. It begins with the preposition with, and it ends with the noun nuts.
The whole phrase is telling us more about the cake. Cake is a noun. It tells us which cake fell. Since it is answering one of the adjective questions, it is acting as an adjective modifying the noun cake.
Onto the floor is telling us more about where the cake fell. Fell is a verb. Since it is answering one of the adverb questions, it is acting as an adverb modifying the verb fell.
with nuts = prepositional phrase acting as adjective (modifying cake)
with = preposition
nuts = object of the preposition (noun)
onto the floor = prepositional phrase acting as adverb (modifying fell)
onto = preposition
floor = object of the preposition (noun)
the = adjective modifying floor
Random Tip: Subjects will never be in a prepositional phrase.
More Sentence Diagramming, Please!
The sentence diagram below shows you more about diagramming these guys. Notice that one of the phrases is branching off the subject (a noun or pronoun) and one is branching off of the verb.
Remember that adjectives modify nouns and pronouns and adverbs modify verbs, adjectives, or other adverbs. Can you guess which phrase is acting as an adjective and which is acting as an adverb?
You're getting so smart that I'm sure you can figure it out!