Commas
Punctuation and Capitalization
Commas
Commas (,) are punctuation marks that help readers understand a sentence by introducing a pause at key points. Be sure you understand how to use commas in the following situations.
COMMAS BETWEEN ITEMS IN A SERIES
Use commas to separate three or more items in a series. This includes the last item in the series, which usually has and before it.
Last semester I took math, reading, and composition.
Students may take the course as a regular classroom course, as an online course, or as a distance learning course.
COMMAS BETWEEN COORDINATE ADJECTIVES
Coordinate adjectives are two or more adjectives that independently modify the same noun and are separated by commas. Coordinate adjectives can be separated by the word and.
It was a long, hard, complicated test.
Do not use a comma between the final adjective and the noun it modifies.
Cumulative adjectives modify the same noun but form a unit and are not separated by commas. Cumulative adjectives cannot be joined by the word and.
Our team wants to win the big regional sales trophy.
All of the words in italics are adjectives, but they build on each other. Moving left from trophy, each adjective becomes part of a larger unit.
COMMAS IN COMPOUND SENTENCES
A compound sentence contains two independent clauses (sentences) joined by one of these words — and, but, for, nor, or, so, yet. Use a comma before the joining word to separate the two clauses.
Tom missed class yesterday, and he texted me to ask what he missed.
I would have been happy to help him, but I was absent too.
I told him I wasn’t there, so he said he would e-
A comma by itself cannot separate two sentences: Doing so creates a run-
A comma is not needed if the word and, but, for, nor, or, so, or yet joins two sentence elements that are not independent clauses.
COMMAS AFTER INTRODUCTORY WORD GROUPS
Use a comma after an introductory word or word group. An introductory word group can be a word, a phrase, or a clause. The comma lets your readers know when the main part of the sentence is starting.
| INTRODUCTORY WORD | Finally, I finished the job. |
| INTRODUCTORY PHRASE | According to the paper, the crime rate went down. |
| INTRODUCTORY CLAUSE | As you know, the store is going out of business. |
COMMAS AROUND APPOSITIVES AND INTERRUPTERS
For more on appositives, see “Sentence Variety” in Chapter 17.
An appositive, a phrase that renames a noun, comes directly before or after the noun.
Dick, my neighbor, has a new job.
Apartment prices are high at Riverview, the new complex.
An interrupter is an aside or transition that interrupts the flow of a sentence and does not affect its meaning.
Campus parking fees, you should know, are going up by 30 percent.
A six-
COMMAS AROUND ADJECTIVE CLAUSES
An adjective clause is a group of words that often begins with who, which, or that; has a subject and verb; and describes the noun that comes before it in a sentence. An adjective clause may or may not be set off from the rest of the sentence by commas depending on its meaning in the sentence.
If an adjective clause can be taken out of a sentence without completely changing the meaning, put commas around the clause.
SuperShop, which is the largest supermarket in town, was recently bought by Big Boy Markets.
I have an appointment with Dr. Kling, who is the specialist.
If an adjective clause is essential to the meaning of a sentence, do not put commas around it. You can tell whether a clause is essential by taking it out and seeing if the meaning of the sentence changes significantly, as it would if you took the clauses out of the following examples:
The hair salon that I liked recently closed.
Salesclerks who sell liquor to minors are breaking the law.
COMMAS WITH QUOTATION MARKS
Quotation marks are used to show that you are using a direct quotation, repeating exactly what someone said or wrote. Generally, use commas to set off the words inside quotation marks from the rest of the sentence.
“Excuse me,” said the old woman in back of me. “Did you know,” she asked, “that you just cut in front of me?”
I exclaimed, “Oh, no. I’m so sorry!”
Notice that a comma never comes directly after a quotation mark.
COMMAS IN ADDRESSES
Use commas to separate the elements of an address included in a sentence. However, do not use a comma before a zip code.
My address is 4498 Main Street, Bolton, Massachusetts 01740.
If a sentence continues after the address, put a comma after the address. Also, use a comma after individual elements used to name a geographical location such as a city and state.
The house was moved from Cripple Creek, Colorado, to the lot on Forest Street.
COMMAS IN DATES
Separate the day from the year with a comma. If you give only the month and year, do not separate them with a comma.
She wrote the letter on April 1, 2009.
The next session is in January 2011.
If a sentence continues after a date that includes the day, put a comma after the date.
He waited until April 15, 2010, to file his 2008 tax return.
COMMAS WITH NAMES
Put commas around the name of someone you are addressing by name.
Don, I want you to come look at this.
Unfortunately, Marie, you need to finish the report by next week.
COMMAS WITH YES OR NO
Put a comma after the word yes or no in response to a question.
No, that isn’t what I meant. [To express a strong emotion, an exclamation mark is sometimes used instead of a comma: No! That is not what I meant. A word or phrase that expresses emotion and stands alone (like No!) is called an interjection.]