Prepositional Phrases

Nouns, pronouns, verbs, adjectives, and adverbs are also frequently described or limited in the same way by an element or group of words called a prepositional phrase. This usually consists of a noun, pronoun, or gerund whose exact relationship to the modified word is shown by means of a preposition. The preposition is placed before the modifying noun or pronoun and its adjective modifiers.

Heavy automobiles with large tires run smoothly over rough roads.

With large tires is a prepositional phrase, consisting of the preposition with and its object tires; the phrase modifies or characterizes automobiles.

Over rough roads is a prepositional phrase which characterizes run.

A prepositional phrase characterizing a noun is called an adjective prepositional phrase. One characterizing a verb is called an adverbial prepositional phrase.