The Printable KISS Grammar Workbooks Nov. 24, 2006

How Prepositional Phrases Work in a Sentence

     Every word in a sentence has a job to do. That job is called its “function.” The function of subjects is to name what the sentence is about. Verbs say something about the subject(s). Some verbs raise the question “whom or what?” The nouns or adjectives that answer that question function as complements. 

     This subject / verb / optional complement pattern (S/V/C) is the most important part of any sentence. Remember that conjunctions (“and,” “or,” and “but”) can join two or more subjects, verbs, complements, adjectives or adverbs within one sentence.

     Almost every word in every English sentence describes (modifies) the words in an S/V/C pattern. You have already learned how adjectives and adverbs modify, and thus grammatically connect to, subjects, verbs, and complements. 

     Almost all prepositional phrases function as adjectives or adverbs:

Mr. Green Frog lives {in a pond}.
Just like an adverb would, “in a pond” describes where he lives. Similarly, in the sentence
The squirrels {in the tree} were having fun (DO).
the prepositional phrase “in the tree” identifies which squirrels the sentence is about and thus functions as an adjective.

     Sometimes more than one prepositional phrase will modify the same word:

Mr. Green Frog will be {in the pond} {for a few hours}

In this sentence, “in the pond” tells where he will be, and “for a few hours” tells  how long he will be there. 

      But a prepositional phrase can also modify a word in another prepositional phrase:

The squirrels scampered off {among the branches} {of the oak tree}.

In this sentence, “of the oak tree” modifies “branches” and thus functions as an adjective. The “among the branches” phrase modifies “scampered.” In other words, the “of the oak tree” phrase connects to the verb because it is connected to “branches.”