Ten Rules

 Rules  | References

1. Use commas to set off

Green check mark Conjunctive adverbs:

Thus, I must withdraw as chairperson for this issue because of a conflict of interest.

I must withdraw as chairperson for this particular issue, however, because of a conflict of interest.

I will temporarily withdraw as chairperson; however, there is no conflict of interest.

Green check mark Geographical names:

This university’s campus is in Millersville, Pennsylvania, and is in the southeastern part of the state.

Green check mark Items in dates if the day comes after the month.

After the month:
Is it wise to continue the semester until May 15, 2001, this year?

Before the month the comma is not needed:
It continued until 15 May 2003.
Note: Traditionally, this has been the British method, but it is being utilized more frequently lately in the U.S. Check your style book.

No comma where there is just the month and year:
It continued through May 1980.

Green check mark Addresses (except the street name and number)

George W. Bush will enjoy staying at 1500 Pennsylvania Avenue, Washington, D.C. again; but he might get homesick for Texas or Maine.

Green check mark Enclose degrees or titles used after names.

Stephen Sondholm, Ph.D., is teaching this course.
Dr. Stephen Sondholm is teaching this course.
This course is taught by professor Sondholm.

Green check mark The rule for adding the title Jr. or Sr. following a name is changing.
Check your professor, editor, or style book.

Traditional: Martin Luther King, Jr., is revered in this town.

More recently we are seeing: Martin Luther King Jr. is revered in this town.

Middle ground: Martin Luther King, Jr. is revered in this town.

2. Use commas to set off direct quotations and after the first part of
a quotation in a sentence.

  1.  He said, I should have gotten an A- in that course.”
  2.  We have finally, she said proudly, finished a project without a group fight.”

(Note: In the U.S., place punctuation before open and
inside close quotes.)

3. Use commas to separate three or more words, phrases, or clauses in a series.  When writing conservatively or when misreading is particularly dangerous, use a comma before the conjunction and last item in the series.

Green check mark Jenny loathed spinach, dates and kale; she refused to eat them under all circumstances.

X mark (The less effective choice for most professional and academic papers. No comma is needed here:
Sarah enjoyed
neither spinach nor kale.

Green check mark Where misunderstanding is dangerous, include a comma before the conjunction: Sarah is deathly allergic to shellfish, mustard, and nuts.  If she is accidentally exposed and goes into anaphylactic shock, please administer the EpiPen she keeps in her purse.

Green check mark Note: Stylesheets vary on whether there should be a comma before the conjunction prior to the final item in the series. Using a comma in that position is never wrong, and can decrease the chances of misreading.

John is convinced that he loves Sarah, Mary, and Elaine with all his heart. Sarah, on the other hand, wants a divorce.

Important: Make sure the series items are in the same form. Do not, for example, write …running, jumping, and played.

Examples: Series of single words of like type

Green check mark Nouns:

      vanilla, cinnamon, and nutmeg

Green check mark Past tense verbs:

      ate, played, and slept

Green check mark Gerund (present participle):

      working, playing, sleeping, or bathing

The number of items don’t matter. A series or groups of words must be in the same format. Let’s examine them in sentences:

Green check mark Nouns:

The recipe calls for 1 cup of milk, 3 teaspoons of flour, 2 eggs, and 1/2 tablespoon of vanilla.

Green check mark Verbs:

Though John plays, works, and sleeps with all his energy and focus, he’s best at that last one.

Green check mark Past Tense Verbs:

Johnny saw the mugging, screamed loudly, and cried about it for hours.

(Don’t let the -ing in mugging throw you here. The verbs are saw, screamed, and cried.)

Green check mark Gerund (nouns made from -ing verbs):

The pooches at the dog park were running after the Frisbee, jumping on their owners, or rolling in the dust.

Samantha’s puppy likes sitting, staying, and playing dead. He’s not mastering the ‘leave it’ command, though, snatching  the treat every time.

Use only with a series. No comma here:
John least favorite activity on Fridays is working.

Working is not a verb here; it’s a gerund.

Compare: John’s most favorite furniture on Fridays is the bar stool.

4. Use commas to separate independent clauses when they are joined by conjunctions (any of these seven words known by the mnemonic FANBOYS): for, and, nor, but, or, yet, so.

Why?  Because each independent clause, taken separately, could form its own sentence. When two or more are joined, we call the result a compound sentence.

Sam loves pumpkin pie, and he will eat all year long.

Note that either side of this sentence can stand as a sentence on its own.

Sam loves pumpkin pie.

He will eat it all year long.

5. Place a comma after introductory phrases that tell where, when, why, or how. You can leave it off with short ones (generally taken to be 4 words or fewer), but it’s not a particularly good idea.

Why? Because introductory phrases can draw attention from the subject and verb that come next, making clear communication is less likely. Remember: Your first job is to make the message clearly understood.

Green check mark Where:  In the dust bowl states of the Midwest, it hadn’t rained in seven months.

Green check mark When: During the hot summer of 2012, the temperatures set records.

Green check mark Why: Because Sam found three new gray hairs this morning, she went to the pharmacy and bought hair dye.

Green check mark How: By chewing an aspirin, John hoped to ease the effects of his heart attack before the EMTs arrived.

6. Use a comma when an introductory phrase begins with:

Green check mark -ing + verb:

Example: Having finally made up with Sally, James couldn’t wait for the wedding to be over.

Green check mark the infinitive, or ‘to form’ of the verb: to run, to play, to get, etc. (Not sure what an infinitive is? Check out Purdue OWL on infinitives.)

Example: To get my records, I had to send a check for $3.00.

Green check mark Use a comma even after a short to + verb phrase that answers why.

Example: To pass, you must submit an original work of art.
(Why do you need to do that art? To pass!)

7. Use commas to separate long introductory phrases from the actual subject and verb of the sentence.The cutoff length varies, but a good rule of thumb is to use a comma with five or more words.

Green check mark After truly embarrassing myself and my friends, I went back to the office to think about ways to repair my reputation.

X mark (The less effective choice for most professional and academic papers. In the meantime I did yoga and meditated.

8. Use a pair of commas in the middle of the sentence to set off phrases, clauses, and words that are not essential (nonrestrictive) to the meaning of the sentence. Use one comma before to show the beginning of the pause and one at the end to show the end of the pause. If a chunk of sentence (whatever it is) delimits or defines a subject or verb or main clause, it is restrictive; if it merely tacks on some extra information, it is nonrestrictive.

Green check mark Nonrestrictive: Nice to know but not really necessary

Atlanta, which is home of the Braves, really should be able to afford a better team.

Dr. McNairy, who was president of the university, worked very hard on that capital campaign.

The store honored the requests, which were less than 60 days old.

The suspect in the lineup, who owns a red car, committed the crime.

Green check mark Restrictive: Necessary to the meaning.

The suspect in the lineup who has red hair committed the crime.

The store honored the complaints that were less than 60 days

The boat that sailed on October 25 is the one to which we referred
in the contract

9. Use commas to separate two or more coordinate
adjectives that describe the same noun.  
adjectives are adjectives placed next to each other that are equal
in importance.   How can you tell if they are coordinate?

Green check mark First, try adding the word ‘and’ and check the results. Can you add the word and between the adjectives? If that sounds smooth add a comma.

Example: Benjamin is a clumsy, bumptious Maine Coon cat.

In this example, a comma belongs between clumsy and bumptious because they are coordinate adjectives. Test to make certain:
1) Try adding the word ‘and’. Does the phrase still make sense?

Benjamin is a clumsy and bumptious Maine Coon cat.

The logic? One does not have to be clumsy to be bumptious or vice versa. So, clumsy does not tell us about bumptious, but about cat.

Green check mark Second, try reversing the adjectives. Can the adjectives be written in reverse order? If yes, add a comma.
Trust your ears here:

an old, dilapidated building
Here, the words old and dilapidated both tell us about the building.

large, stinky feet
The word large does not tell us about stinky but about feet.

but no comma here:  a white silk gown. 

Hmm…why not?  Because silk doesn’t tell us anything about white, though white does tell us the color of the silk fabric.

a) She has a large, aggressive dog.
b) She has a long haired dog.

When the adjectives are reversed, the sentence still makes sense, so we need a comma with example a: She has an aggressive, large dog. So, these are coordinate adjectives which need a comma. This is not the case with example b: She has a haired long dog.

10. That clauses after nouns are usually essential. No comma is needed in these situations.

  • The word thatafter nouns:
    • The shareware that I downloaded last night is really good.
    • Bananas that are black are usually overripe.
  • The word thatin clauses
    which follow a verb expressing mental action:
    • He thinks that he will get a corner office after the
    • She feels that she deserves a promotion. I believe that
      it was wrong to reject their proposal.
    • They wish that U.S. workers had longer vacations.
    • Human Resources understands that two weeks vacation is
      too short for Europeans.
  • If essential: no comma used
    • A person who smokes can find it hard to get job today.
    • The player with the No. 8 shirt is very talented.
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Purdue University. “The Owl at Purdue.” 2005. Found December 4, 2005.

Proofreading for Commas

“Independent and Dependent Clauses (Definitions)”

“Sentence Punctuation Patterns”

“Q&A.” The Chicago Manual of Style Online.The Chicago Manual of Style.2010. Web. Found 30 May 2014.

Townson University’s Writing Center.Kinds of Sentences and Their Punctuation(n.d.) Web. Found 23 July 2014.

University of Delaware Writing Center. Punctuation Patterns for Several Sentence Types. University of Delaware. Spring 1993. Web. Found December 25, 2006.

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