Monday, July 04, 2005

COMMAS - The (Not-So) Quick & Dirty Guide

From a list of sources compiled by:
Erin Mullarkey, 

Editor, Loose Id Books
Some Basic Definitions
Easy Writer, 2nd edition
Andrea Lunsford 

Noun: A word that names a person, place, object, concept, action, or the like.

Pronoun: A word used in place of a noun.

There are many different kinds of pronouns:
  • Indefinite - any, each, everybody, some
  • Personal - I, you, he, she, it, we, they
  • Possessive - my, mine, our, his, hers, your, their
  • Relative - who, whom, whose, which, that, what, whoever, whomever, whichever, whatever

Clause: A group of words containing a subject and a predicate.

Independent Clause: An independent clause can stand alone as a sentence.

The car hit the tree.

Dependent Clause: A dependent clause cannot stand alone as a sentence, and is dependent on an independent clause.

The car hit the tree that stood at the edge of the road.

In this sentence, that stood at the edge of the road can’t stand alone as a sentence; it depends on the other clause (the car hit the tree) to mean anything.

Subject: The noun or pronoun and related words that indicate who or what a sentence is about.

Predicate: The verb and related words in a clause or sentence. The predicate expresses what the subject does, experiences, or is.

Morgan bought cotton candy, and Erin rode the elephant.

This example sentence has two clauses. The first clause is Morgan bought cotton candy and the second clause is Erin rode the elephant.

In the first clause, Morgan is the subject, and bought cotton candy is the predicate. Both clauses are independent, because they can function all by themselves and don’t need the other clause to be complete.

USING Commas 
The Elements of Style, 4th edition
William Strunk Jr. and E.B. White:

In a series of three or more terms with a single conjunction, use a comma after each term except the last. Thus write:

Red, white, and blue. 
Gold, silver, or copper.
He opened the letter, read it, and made a note of its contents.

This comma is often referred to as the “serial” comma.

The Chicago Manual of Style, 15thedition

The comma…indicates the smallest break in sentence structure. It denotes a slight pause. Effective use of the comma involves good judgment, with ease of reading the end in view.

Serial comma examples from 6.19:
She took a photograph of her parents, the president, and the vice president.

The owner, the agent, and the tenant were having an argument.

The meal consisted of soup, salad, and macaroni and cheese.

John was working, Jean was resting, and Alan was running errands and furnishing food.

NOTE: this last one is a little different, because Alan is doing two things. A pair of actions that are joined by “and” don’t need a comma.

If everyone was doing more than one thing, the sentence could appear like this:
John was working and talking, Jean was resting and thinking, and Alan was running errands and furnishing food. 
Eats, Shoots and Leaves
 Lynne Truss:

You do NOT use a comma for:
It was an endangered white rhino. 
Australian red wines are better than Australian white ones.
This is because, in each of these cases, the adjectives do their jobs in joyful combinations; they are not intended as a list.
The rhino isn’t endangered and white.

The wines aren’t Australian and red.
Parenthetic or Transitional expressions
Easy Writer:

Parenthetical expressions add comments or information. Because they often interrupt the flow of a sentence, they are usually set off with commas.

Some studies, incidentally, have shown that chocolate, of all things, helps to prevent tooth decay.

Transitionals are words such as however and furthermore and other words and phrases used to connect parts of sentences. They are usually set off with commas.

Ceiling fans are, moreover, less expensive than air conditioners.

Ozone is a byproduct of dry cleaning, for example.
The Allyn & Bacon Guide to Writing, 3rdedition

By reading your sentences aloud in a natural voice, you can generally identify parenthetical material interrupting the flow of a sentence. Such material should be set off by pairs of commas. The following are common examples of interrupting material:

Contrasting Elements Introduced by but, not, or although

The man at the front desk, not the mechanic, was the one who quoted me the price.

Word of Direct Address, yes and no, and Mild Interjections

I tell you, Jennifer, your plan won’t work. 

Tag Phrases Citing Sources

This new car, according to the latest government reports, gets below-average mileage.

Attributive Tags Identifying Speaker

“To be a successful student,” my adviser told me, “you have to enjoy learning.”
 Elements of Style:

Never omit one comma and leave the other. There is no defense for such punctuation as:

Marjorie’s husband, Colonel Nelson paid us a visit yesterday.
My brother you will be pleased to hear, is now in perfect health. 

In these examples, the parenthetic expressions (Colonel Nelson and you will be pleased to hear) should have had a comma before and after them.

Introductory elements
Easy Writer:

In general, use a comma after any word, phrase, or clause that precedes the subject of the sentence.

In Fitzgerald’s novel, the color green takes on great symbolic qualities.

To win the contest, Connor needed courage.

Pens poised, we waited for the lecture to begin.

Suddenly, Anisha remembered the answer.

Separating Independent Clauses
Easy Writer:

A comma usually precedes a coordinating conjunction (and, but, for, nor, or, so, or yet) that joins two independent clauses.

Scientists have studied AIDS for more than twenty years, but a vaccine still eludes them.
Chicago Manual of Style
We bolted the door, but the intruder was already inside.

Everyone present was startled by the news, and one man fainted.
When a sentence is composed of a series of short independent clauses with a conjunction joining the last two, commas should appear both between the clauses and before the conjunction.

Donald cooked, Sally trimmed the tree, and Maddie and Cammie offered hors d’oeuvres.

Notice that in all of the examples, the independent clauses are joined by a conjunction like and, or, but.

You cannot use a comma by itself to join together two sentences (two independent clauses.) This is called a “comma splice.” (Put a semicolon there, instead of a comma.)

The Elements of Style:

If two or more clauses are grammatically complete and not joined by a conjunction are to form a single sentence, the proper mark of punctuation is a semicolon.

Mary Shelley’s works are entertaining; they are full of engaging ideas. 
It is nearly half past five; we cannot reach town before dark.

It is, of course, equally correct to write each of these as two sentences, replacing the semicolons with periods.

Mary Shelley’s works are entertaining. They are full of engaging ideas. 
It is nearly half past five. We cannot reach town before dark.

If a conjunction is inserted, the proper mark is a comma.

Shelley’s works are entertaining, for they are full of engaging ideas. 
It is nearly half past five, and we cannot reach town before dark.

Nonrestrictive elements
Easy Writer:

Nonrestrictive elements are clauses, phrases, and words that do not limit, or restrict, the meaning of the words they modify. Since such elements are not essential to the meaning of the sentence, they should be set off from the rest of the sentence with commas.

Restrictive elements, on the other hand, do limit meaning; they should not be set off by commas.


Drivers who have been convicted of drunken driving should lose their licenses.

The clause ‘who have been convicted of drunken driving’ is essential to the meaning because it limits the word it modifies, Drivers, to only those drivers who have been convicted of drunken driving. Therefore the clause is not set off by commas.


The two drivers involved in the accident, who have been convicted of drunken driving,
should lose their licenses.

In this sentence, the clause who have been convicted of drunken driving is not essential to the meaning because it does not limit what it modifies, The two drivers involved in the accident, but merely provides additional information about these drivers. Therefore, the clause is set off with commas.

To decide whether an element is restrictive or nonrestrictive, mentally delete the element, and then see if the deletion changes the meaning of the rest ofthe sentence or makes it unclear. If the deletion does change the meaning, you should probably not set it off with commas. If it does not change the meaning, the element probably requires commas.

Basically, look at your sentence and see if there are parts that are “extra” and not strictly necessary.

John, wearing a dark gold cloak, gestured to Georges, who was wearing a skintight, electric blue bodysuit.

In that sentence, the information I included about the clothes they are wearing is for descriptive purposes and not essential. I could just say “John gestured to Georges”, and the meaning of the sentence is exactly the same. That’s why I used commas to set off my descriptive phrases.

But check this out:

The man wearing a dark gold cloak gestured to the man wearing a skintight, electric blue bodysuit.

If I tried to take out the clothes descriptions there, I would end up with “The man gestured to the man”, which isn’t very helpful or clear. I need the clothing information to distinguish which man is doing what. So, I didn’t use commas, because the information is essential to the meaning of the sentence.

Odds and Ends
Allyn & Bacon

Use commas to separate sentence elements, when failure to separate them would cause confusion.

Confusing: Every time John ate his dog wanted to be fed too. 
Revised: Every time John ate, his dog wanted to be fed too.

Do not use a comma to separate a subject from its verb.

Faulty: The man in the apartment next to mine, swallowed a goldfish. 
Revised: The man in the apartment next to mine swallowed a goldfish.

Do not use a comma after such as.

Amazon links to the books referenced:
Strunk & White - this is a great little book that no writer should be without.
Easy Writer - I used this in a college class; it’s a great quick reference with easy-to-understand language. It gets to the point quickly.
Allyn & Bacon - this was a college textbook on composition; the stuff I pulled out of it all came from a small reference section in the back.
Eats, Shoots & Leaves - a must-read. It’s hilarious and gets the point across clearly.
Chicago Manual of Style - Loose Id Books has adopted this as its style manual. This is the definitive manual on anything you could possibly need to know about grammar and style.
The absolute best online help source, the Purdue Online Writing Lab, has tons of interactive exercises.
Twenty common writing errors and explanations of the rules.
Another really fun grammar site is The Elements of Phyle.

For More on Commas, see also:
An Unkindness of COMMAS

Morgan Hawke


  1. Boy oh boy. I'm bookmarking this, saving it from Erin and I swear this time...I'm getting commas and where they go.

    Thanks Morgan and Erin!

  2. :) I'm a grammar dork, so I had fun doing it. It's the bare bones of comma-ology, anyway!

  3. I Really, REALLY need comma help. I tend to pull "Mark Twain's". I write the text and sprinkle the commas in -- where ever.

    Morgan Hawke