A prepositional phrase is a preposition, its object, and any words that describe the object: with the red kite, after lunch. The whole phrase works like one modifier, and it can do one of two jobs.
- An adjective phrase modifies a noun or pronoun. It tells which one or what kind: “the girl with the kite.”
- An adverb phrase modifies a verb, adjective or adverb. It tells where, when, how or why: “ran to the park,” “left after lunch.”
Key idea
Ask which word the phrase tells more about. A noun: it is an adjective phrase. A verb (or an adjective or adverb): it is an adverb phrase.
Why it works
Putting a phrase next to the right word keeps meaning clear. “I saw a deer with binoculars” could mean the deer had binoculars. Knowing what a phrase modifies is the first step to fixing a misplaced modifier, and it decides where the phrase hangs in a diagram.
Worked example: Which word does it modify?
“Leo kicked the ball over the fence.” What does over the fence modify?
- The nearest noun is ball, but the phrase doesn’t tell which ball.
- It tells where Leo kicked: it modifies the verb kicked.
Answer: kicked: an adverb phrase
Worked example: Two phrases in a row
“The box of crayons on the shelf is mine.”
- of crayons tells which box: adjective phrase.
- on the shelf also tells which box: another adjective phrase.
Answer: two adjective phrases, both modifying box
Common mistake
Deciding by position, as if a phrase always modifies the word right before it. Ask the questions: which one? (adjective phrase) or where, when, how, why? (adverb phrase).