D. Commas
Chapter
Commas
Many students are uncertain how to use a comma correctly. This is likely because commas can be used in a variety of ways. Look at some of the following sentences to see how you might use a comma when writing a sentence:
- Introductory word: Personally, I think the practice is helpful.
- Lists: The barn, the tool shed, and the back porch were destroyed by the wind. (Note — the comma before “and” in a list is called an Oxford comma and is an optional style choice, but be consistent.)
- Coordinating adjectives: He was tired, hungry, and late.
- Conjunctions in compound sentences: The bedroom door was closed, so the children knew their mother was asleep.
- Interrupting words: I knew where it was hidden, of course, but I wanted them to find it themselves.
- Dates, addresses, greetings, and letters: The letter was postmarked December 8, 1945, in San Francisco, California.
- Modifying phrases: Sam focused on the detailed brush work, consisting as it did of many tiny dots.
Commas after an Introductory Word or Phrase
You may notice a comma that appears near the beginning of the sentence, usually after a word or phrase. This comma lets the reader know where the introductory word or phrase ends and the main sentence (usually beginning with the subject) begins.
Example 1
Without spoiling the surprise, we need to tell her to save the date.
In this sentence, without spoiling the surprise is an introductory phrase, while we need to tell her to save the date is the main clause. Notice how they are separated by a comma. When only an introductory word appears in the sentence, a comma still follows the introductory word, as in this example:
Example 2
Unfortunately, she already had plans for that day.
Exercise 1: Look for the introductory word or phrase. On your own sheet of paper, copy the sentence and add a comma to correct the sentence.
- Suddenly the dog ran into the house.
- In the blink of an eye the kids were ready to go to the movies.
- Confused he tried opening the box from the other end.
- Every year we go camping in the woods.
- Without a doubt green is my favorite color.
- Hesitating she looked back at the directions before proceeding.
- Fortunately the sleeping baby did not stir when the doorbell rang.
- Believe it or not the criminal was able to rob the same bank three times.
Commas in a List of Items
When you want to list several nouns in a sentence, you separate each word with a comma. This allows the reader to pause after each item and identify which words are included in the grouping. When you list items in a sentence, put a comma after each noun, then add the word and before the last item. However, you do not need to include a comma after the last item. Also, the comma before the and is known as an “Oxford comma,” and although it is optional, it can avoid ambiguity.
Example 3
We’ll need to get flour, tomatoes, and cheese at the store.
The pizza will be topped with olives, peppers, and pineapple chunks.
We could add some bacon, prosciutto, etc.
Commas and Coordinating Adjectives
You can use commas to list both adjectives and nouns. A string of adjectives that describe a noun are called coordinating adjectives. These adjectives come before the noun they modify and are separated by commas. One important thing to note, however, is that, unlike listing nouns, the word and does not always need to be before the last adjective.
Example 4
It was a bright, windy, clear day.
Our kite glowed red, yellow, and blue in the morning sunlight.
Exercise 2: On your own sheet of paper, use what you have learned so far about comma use to add commas to the following sentences.
- Monday Tuesday and Wednesday are all booked with meetings.
- It was a quiet uneventful unproductive day.
- When I visit my aunt Marie and their dogs I bring my dogs Bacon and Eggs.
- We’ll need to prepare statements for the Franks Todds and Smiths before their portfolio reviews next week.
- Michael Nita and Desmond finished their report last Tuesday.
- With cold wet aching fingers he was able to secure the sails before the storm.
- He wrote his name on the board in clear precise delicate letters.
- I am excited to travel to the U.K. where I’ll see my parents Elton John and the queen.
Commas before Conjunctions in Compound Sentences
Commas are used to join two independent clauses. The comma comes after the first independent clause and is followed by one of the coordinating conjunctions: for, and, not, but, or, yet, so (FANBOYS).
Note that a comma is not used before conjunctions that join a phrase to an independent clause. For more information and practice, see “G. Coordination and Subordination.”
Example 5: Commas joining two independent clauses
He missed class today, and he thinks he will be out tomorrow, too.
He says his fever is gone, but he is still very tired.
Example 6: No comma needed when joining a phrase to a clause
Exercise 3: On your own sheet of paper, create a compound sentence by combining the two independent clauses with a comma and a coordinating conjunction.
- The presentation was scheduled for Monday. The weather delayed the presentation for four days.
- He wanted a snack before bedtime. He ate some fruit.
- The patient is in the next room. I can hardly hear anything.
- We could go camping for vacation. We could go to the beach for vacation.
- I want to get a better job. I am taking courses at night.
- I cannot move forward on this project. I cannot afford to stop on this project.
- Patrice wants to stop for lunch. We will take the next exit to look for a restaurant.
- I’ve got to get this paper done. I have class in ten minutes.
- The weather was clear yesterday. We decided to go on a picnic.
- I have never dealt with this client before. I know Leonardo has worked with them. Let’s ask Leonardo for his help.
Commas before and after Modifying Words and Phrases
In conversations, you might interrupt your train of thought by giving more details about what you are discussing. In a sentence, you might interrupt your train of thought with a word or phrase. This may be a parenthetical thought (an aside) or a modifying phrase. These types of words and phrases can appear at the beginning or middle of a sentence. When the interrupting words appear at the beginning of the sentence, a comma appears after the word or phrase.
Example 7
If you can believe it, people once thought the sun and planets orbited around Earth.
Luckily, some people questioned that theory.
When modifying phrases come in the middle of a sentence, they are separated from the rest of the sentence by commas. You can determine where the commas should go by looking for the part of the sentence that is not essential for the sentence to make sense.
Example 8
An Italian astronomer, Galileo, proved that Earth orbited the sun.
We have known, for hundreds of years now, that the Earth and other planets exist in a solar system.
Exercise 4: On your own sheet of paper, copy the sentence and insert commas to separate the modifying phrases from the rest of the sentence.
- I asked my neighbors the retired couple from Florida to bring in my mail.
- Without a doubt his work has improved over the last few weeks.
- Our professor Mr. Alamut drilled the lessons into our heads.
- The meeting is at noon unfortunately which means I will be late for lunch.
- We came in time for the last part of dinner but most importantly we came in time for dessert.
- All of a sudden our network crashed and we lost our files.
- Quick hand the wrench to me before the pipe comes loose again.
Tip
Modifying phrases and clauses can be “set off” by either commas or parentheses, depending on how important the information is to the reader. Consider the following examples:
- Arcade Fire, my favorite Canadian band, has several songs about growing up in the 80s.
- Arcade Fire (my favorite Canadian band) has several songs about growing up in the 80s.
- Arcade Fire, my favorite (Canadian) band, has several songs about growing up in the 80s.
Commas in Dates, Addresses, and the Greetings and Closings of Letters
Commas are used when you write the date (such as in cover letters and e-mails), when you include an address, and when you greet someone.
If you are writing out the full date, add a comma after the day and before the year (see #1, below). You do not need to add a comma when you write the month and day or when you write the month and the year (# 2 and #3). If you need to continue the sentence after you add a date that includes the day and year, add a comma after the end of the date (#4).
Example 9
- The letter is postmarked May 4, 2001.
- Her birthday is May 5.
- He visited the country in July 2009.
- I registered for the conference on March 7, 2010, so we should get our tickets soon.
Also use commas when writing addresses and locations. When you include an address in a sentence, be sure to place a comma after the street and after the city. Do not place a comma between the state and the zip code. As with writing a date, if you need to continue the sentence after adding the address, simply add a comma after the address.
Example 10
We moved to 4542 Boxcutter Lane, Hope, Missouri 70832.
After moving to Boston, Massachusetts, Eric used public transportation to get to work.
Greetings are also separated by commas. When writing an e-mail or a letter, add a comma after the greeting word or the person’s name. Also include a comma after the closing, which is the word or phrase you put before your signature.
Example 11
Hello,
I would like more information about your job posting.
Thank you,
Anita Al-Sayf
Dear Anita,
Thank you for your letter. Please read the attached document for details.
Sincerely,
Jack Fromont
Exercise 5: On your own sheet of paper, use what you have learned about using commas to edit the following letter.
14 Taylor Drive Apt. 6
New Castle Maine 90342 Dear Mr. TimmonsThank you for agreeing to meet with me. I am available on Monday the fifth. I can stop by your office at any time. Is your address still 7309 Marcourt Circle #501? Please get back to me at your earliest convenience.Thank youAlexa
Exercise 6: On your own sheet of paper, use what you have learned about comma usage to edit the following paragraphs.
- My brother Nathaniel is a collector of many rare unusual things. He has collected lunch boxes limited edition books and hatpins at various points of his life. His current collection of unusual bottles has over fifty pieces. Usually he sells one collection before starting another.
- Our meeting is scheduled for Thursday March 20. In that time we need to gather all our documents together. Alice is in charge of the timetables and schedules. Tom is in charge of updating the guidelines. I am in charge of the presentation. To prepare for this meeting please print out any e-mails faxes or documents you have referred to when writing your sample.
- It was a cool crisp autumn day when the group set out. They needed to cover several miles before they made camp so they walked at a brisk pace. The leader of the group Garth kept checking his watch and their GPS location. Isabelle Raoul and Maggie took turns carrying the equipment while Carrie took notes about the wildlife they saw. As a result no one noticed the darkening sky until the first drops of rain splattered on their faces.
- Please have your report complete and filed by April 15 2010. In your submission letter please include your contact information the position you are applying for and two people we can contact as references. We will not be available for consultation after April 10 but you may contact the office if you have any questions. Thank you HR Department.