The comma is a punctuation mark that indicates a pause in a sentence or a separation of things in a list. 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.
- 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.
- Nonrestrictive adjective clauses: Jimmy Carter, who was the first president from Georgia, visited Atlanta last week.
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 begins.
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 sentence. Notice how they are separated by a comma. When only an introductory word appears in the sentence, a comma also follows the introductory word.
Ironically, she already had plans for that day
Look for the introductory word or phrase. Then 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.
- 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.
We’ll need to get flour, tomatoes, and cheese at the store.
The pizza will be topped with olives, peppers, and pineapple chunks.
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.
It was a bright, windy, clear day.
Our kite glowed red, yellow, and blue in the morning sunlight.
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.
- 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.
Commas before Conjunctions in Compound Sentences
Commas are used to separate two independent clauses. The comma comes after the first independent clause and is followed by a conjunction, such as for, and, or but.
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.
Commas before and after Interrupting Words
In conversations, you might interrupt your train of thought by giving more details about what you are talking about. In a sentence, you might interrupt your train of thought with a word or phrase called interrupting words. Interrupting words can come 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.
If you can believe it, people once thought the sun and planets orbited around Earth.
Luckily, some people questioned that theory.
When interrupting words 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.
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.
Insert commas to separate the interrupting words 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.
- Alex hand the wrench to me before the pipe comes loose again.
Commas in Dates, Addresses, and the Greetings and Closings of Letters
You also use commas when you write the date, such as in cover letters and emails. Commas are used when you write the date, 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. You do not need to add a comma when you write the month and day or when you write the month and the year. 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.
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.
You also use commas when you include 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. Like a date, if you need to continue the sentence after adding the address, simply add a comma after the address.
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 you write an email or a letter, you add a comma after the greeting word or the person’s name. You also need to include a comma after the closing, which is the word or phrase you put before your signature.
I would like more information about your job posting.
Dear Mrs. Al-Sayf,
Thank you for your letter. Please read the attached document for details.
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 emails 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.
- Punctuation marks provide visual cues to readers to tell them how to read a sentence. Punctuation marks convey meaning.
- Commas indicate a pause or a list in a sentence.
- A comma should be used after an introductory word to separate this word from the main sentence.
- A comma comes after each noun in a list. The word and is added before the last noun, which is not followed by a comma.
- A comma comes after every coordinating adjective except for the last adjective.
- Commas can be used to separate the two independent clauses in compound sentences as long as a conjunction follows the comma.
- Commas are used to separate interrupting words from the rest of the sentence.
- When you write the date, you add a comma between the day and the year. You also add a comma after the year if the sentence continues after the date.
- When they are used in a sentence, addresses have commas after the street address, and the city. If a sentence continues after the address, a comma comes after the zip code.
- When you write a letter, you use commas in your greeting at the beginning and in your closing at the end of your letter.
The semicolon (;) can be used in a variety of ways. The semicolon indicates a break in the flow of a sentence, but functions differently than a period or a comma. When you encounter a semicolon while reading aloud, this represents a good place to pause and take a breath.
Semicolons to Join Two Independent Clauses
Use a semicolon to combine two closely related independent clauses. Relying on a period to separate the related clauses into two shorter sentences could lead to choppy writing. Using a comma would create an awkward run-on sentence.
Correct: Be sure to wear clean, well-pressed clothes to the interview; appearances are important.
Choppy: Be sure to wear clean, well-pressed clothes to the interview. Appearances are important.
Incorrect: Be sure to wear clean, well-pressed clothes to the interview, appearances are important.
In this case, writing the independent clauses as two sentences separated by a period is correct. However, using a semicolon to combine the clauses can make your writing more interesting by creating a variety of sentence lengths and structures while preserving the flow of ideas.
Semicolons to Join Items in a List
You can also use a semicolon to join items in a list when the items in the list already require commas. Semicolons help the reader distinguish between items in the list.
Correct: The color combinations we can choose from are black, white, and grey; green, brown, and black; or red, green, and brown.
Incorrect: The color combinations we can choose from are black, white, and grey, green, brown, and black, or red, green, and brown.
By using semicolons in this sentence, the reader can easily distinguish between the three sets of colors.
Use semicolons to join two main clauses. Do not use semicolons with coordinating conjunctions such as and, or, and but.
Correct the following sentences by adding semicolons. If the sentence is correct as it is, write OK.
- I did not notice that you were in the office I was behind the front desk all day.
- Do you want turkey, spinach, and cheese roast beef, lettuce, and cheese or ham, tomato, and cheese?
- Please close the blinds there is a glare on the screen.
- Unbelievably, no one was hurt in the accident.
- I cannot decide if I want my room to be green, brown, and purple green, black, and brown or green, brown, and dark red.
- Let’s go for a walk the air is so refreshing.
- Use a semicolon to join two independent clauses.
- Use a semicolon to separate items in a list when those items already require a comma.