English grammar

Module 6, Prepositions, Lesson 11:

Commas with Prepositional Phrases

English grammar

Restrictive or Essential Adjective Phrases

A restrictive phrase, or essential phrase, is one that is necessary to the sentence. It limits or restricts the word it is modifying so that the reader knows which noun is being referred to. Restrictive phrases do not have commas around them.
The newspapers \in the attic are garbage. The newspapers \in the den are not garbage.
Without the phrase, I might throw out the wrong newspapers.
A nonrestrictive, or nonessential, phrase is one that is not necessary to the sentence. It adds information that is not needed. Nonrestrictive phrases need commas around them.
My father, \with his fear of crowds, did not come with us to the state fair.
I don't need to know about his fear of crowds to know which father I am talking about.

Commas with Adverb Phrases

Adverb phrases at the beginning of the sentence, now introductory prepositional phrases, are usually separated from the sentence by a comma unless they are very short (three words or fewer) and it is easy to tell where the phrase ends.

In the morning we got up and got ready for work.
In the morning, we got up and got ready for work.
(Short phrase okay with or without a comma.)

This is one of the few places where how a sentence sounds determines the punctuation.

Without my work, I was tempted to skip class.
(Short, but pauses. It is obvious that work does not describe I.)

Prepositional phrases layered together usually have a comma.

On the morning before my birthday, my parents surprised me with a trip to Hawaii.

Commas are especially important if the object of the preposition is a verb acting like a noun. Otherwise, the results can be funny.

After vacuuming my brother collapsed on the couch. (Was someone vacuuming your brother?)
After vacuuming, my brother collapsed on the couch. (Comma is necessary)

Sometimes for effect, writers turn the whole sentence around, using the prepositional phrase first, then the verb, and finally the subject.

Down the stream paddled the kayakers.

This is not an example of an introductory phrase and does not need a comma.

Practice What You've Learned

English grammar

Part 1

Decide whether the bold-faced adjective prepositional phrases are restrictive (no commas necessary), or nonrestrictive (commas needed). Commas have been intentionally left out.
The teacher with her manual went over the answers to the exercise.
restrictive / nonrestrictive
The man with the mustache is our principal.
restrictive / nonrestrictive
This little dog with its broken paw was rescued from the middle of a busy street.
restrictive / nonrestrictive
The horse with the dark mane is a buckskin.
restrictive / nonrestrictive
The ski instructor in spite of the cold patiently explained things over and over.
restrictive / nonrestrictive
My new bicycle with its bright red paint job already has a flat tire.
restrictive / nonrestrictive
The cheese in the plastic wrap doesn't taste like real cheese.
restrictive / nonrestrictive
My dog with her fear of fireworks hates the Fourth of July.
restrictive / nonrestrictive
The player on first base is watching the pitcher carefully.
restrictive / nonrestrictive
The rain like an omen suddenly turned the sky dark and spooky.
restrictive / nonrestrictive

Part 2

Decide whether the bold-faced phrase needs a comma or not. If it could go either way, choose no comma.
According to the fairy tales knights and dragons are enemies.
comma / no comma
At home we found the dog had shredded several boxes.
comma / no comma
After her trip to France Sara returned with thousands of pictures.
comma / no comma
Before eating the boys' mother told them to wash their hands.
comma / no comma
In a bag under my bed were the new shoes I had lost.
comma / no comma
Before ruling the judge made sure to hear both sides of the story.
comma / no comma
After school we are going to the library to study.
comma / no comma
On the flight to Florida we watched my favorite movie.
comma / no comma
On the sidewalk in front of our house is a giant pile of snow.
comma / no comma
Along the fence in my backyard I am growing red climbing roses.
comma / no comma