1.19 The Comma
Some of the basic rules of commas have been covered in other portions of this book. The information below reviews the basic rules and includes a few more.
The comma is the most widely misused form of punctuation. If you remember that the comma is used for two basic purposes – to separate or to enclose – you will easily understand how to use it correctly.
Commas to separate
Commas are used to separate items in a sentence or separate elements. Each of these purposes are elaborated below.
1. Commas are used to separate items in a sentence.
In fact, they can be used to separate any of the following:
- items in a series
- information that comes before the main clause
- two independent clauses joined by a FANBOYS
1a. Commas used to separate items in a series
Refer to the examples below.
| Rule | Examples | A note about the final comma in a series |
|---|---|---|
|
Use a comma to separate each item in a series; a series is a group of three or more items having the same function and form in a sentence. |
We bought a printer, a desk, and a coffee maker for our new office. (a series of words) Our manager promised to review the report, contact our client, and hold a meeting with shareholders. (a series of phrases) We were relieved to learn that our production line was on time, that our manager was satisfied with the costing, and that the project would soon be over. (series of clauses) |
Technically, it’s grammatically optional in American English. However, depending on the list you are writing out, omitting it can lead to some confusion. APA Style Guide recommends using a comma before the word “and”. |
1b. Commas used to separate information that comes before the main clause (independent clause)
A comma tells readers that the introductory material has come to a close and that the main part of the sentence is about to begin.
Introductory material can include the following:
- a word
- a phrase
- a clause
| Examples: A word before the main clause |
Examples: A phrase before the main clause | Examples: A clause before the main clause |
|---|---|---|
|
John, you really should consider joining our department’s soccer team. |
On Mondays, we often have impromptu meetings. |
Because we realize the importance of developing our business communications skills, we are happy to be taking a business communications course. |
|
Indeed, it is an excellent way to get some exercise and meet colleagues. |
With your help, I’m sure we can achieve our marketing goals. |
As soon as we finish the initial phase, we will present a progress report to our manager. |
|
However, do remember that joining is entirely voluntary. |
Of all the marketing proposals, Alexander’s proposal was the most comprehensive. |
|
|
To help you keep better records, we have created a user-friendly form. |
1c. Commas used to separate two independent clauses joined by a FANBOYS
- John completed the audit, and Mary wrote the report.
- We need to upgrade our software system, but we don’t have enough money in the budget.
Note: No comma is included in the example below because the information following “and” is not an independent clause (complete sentence).
- John completed the proposal and gave a presentation on it.
2. Commas are used to separate elements.
- elements in dates, titles, addresses, numbers
- modifiers (adjectives) that convey separate meanings
- participle phrases (at both the beginning and end of sentences)
2a. Commas used to separate elements in dates, titles, addresses, and numbers
- Dates: Separate years from days.
- Addresses: Separate cities from provinces
- Titles: Separate the title from the rest of the sentence with a pair of commas if a title follows a name.
- Numbers: In numbers more than four digits long, use commas to separate the numbers into groups of three, starting from the right.
| Dates |
On Monday, November 26, 2016, we initiated a new benefits program. |
|---|---|
| Addresses |
Our main branch is located in Toronto, Ontario. |
| Titles |
Stan Zoldos, C.P.A, will be looking after your account. |
| Numbers | With more than 2,000 employees, we are proud of our growth. |
2b. Use a comma to separate coordinate adjectives
Use a comma between coordinate adjectives (adjectives that separately modify a noun).
To determine when adjectives are coordinate, apply two simple tests to be sure:
- First, place the word “and” between the two adjectives.
- Second, reverse them. If, in both instances, the resulting phrase still sounds appropriate, we are most likely dealing with coordinate adjectives and should use a comma between them.
The four examples make sense if the test is applied. Therefore, the word “and” could be replaced with a comma.
- We must travel over several narrow and winding roads.
or
We must travel over several winding and narrow roads. - He is a strong and healthy man.
or
He is a healthy and strong man.
Replacing “and” with a comma results in
- We must travel over several narrow, winding roads.
- He is a strong, healthy man.
Cumulative adjectives are adjectives that build on each other to modify a noun in contrast to coordinate adjectives. Since cumulative adjectives work together to modify the noun, they are arranged in a particular sequence without a comma to separate them.
| Coordinate Adjectives |
His concise, up-to-date report was impressive. |
The new, improved system is working well. |
|---|---|---|
| Cumulative Adjectives |
Sarah purchased a bright red office chair. (bright describes red) |
A large furry insect crawled across the floor during our meeting. (large and furry describe the insect) |
2c. Use a comma to separate participle phrases (at both the beginning and end of sentences)
| Participial phrase at the beginning of a sentence |
Creating a well-functioning team, Evelyn was able to harness individual employees’ strengths. |
Producing no green-house gas emissions, electric cars offer drivers an eco-friendly option. |
|---|---|---|
| Participial phrase at the end of a sentence |
Indigenous entrepreneurship is and will continue to grow in the next decade, making it a critical part of Canada’s economy. |
Several no chip and PIN cards are susceptible to security breaches, causing many users apprehension. |
Listed above, the comma functions to separate items or elements. It does not matter what the items are.
Commas to enclose
Use commas to enclose parenthetic expressions within a sentence. Parenthetic expressions provide an extra element of description to the sentence; the information in such expressions can be removed without changing the meaning of the sentence.
Think of parenthetic expressions as extra, unnecessary, or non-restrictive information.
Parenthetic expressions include
- direct addresses,
- appositives, and
- non-restrictive (also called unnecessary or extra) clauses.
1. Commas used for direct addresses
Use a comma to indicate a direct address. When a writer names the person to whom they are writing or addresses their audience, it is called direct address.
- I think, John, that your analysis is an accurate portrayal of current market trends.
- Yes, Sylvia, your comments on current grammatical usage are correct.
Note: The information enclosed in the commas is unnecessary. It could be left out without changing the meaning of either sentence.
2. Commas used to set off non-restrictive appositives
An appositive is a noun or noun phrase that renames a nearby noun. Nonrestrictive appositives offer nonessential information. Nonrestrictive appositives are set off with commas; restrictive appositives are not.
- Margaret Atwood, a Canadian writer, has a broad international following.
- Cannabix Technologies, a medical marijuana producer, is intending to expand its facilities.
Note: The information enclosed in the commas is unnecessary. It could be left out without changing the meaning of either sentence.
3. Commas used to enclose non-restrictive clauses
Non-restrictive clauses are also called unnecessary or extra clauses.
- Steve Paikin, whose show you watch, will host the seminar.
- The Tesla Model S, which propelled Elon Musk to the top of the automobile industry, is now available in many countries.
Note: The information enclosed in the commas is unnecessary. It could be left out without changing the meaning of either sentence.
4. Do not use commas if the information in the clause is restrictive (necessary) to the meaning of the sentence
- The store honored the complaints that were less than 60 days old. (only complaints less than 60 days old will be honoured; others will not be)
- The ring that she had custom-made was stolen from the vault. (the custom-made ring was stolen; not any other ring)
- Employees who do not have a parking permit will not have access to the parking lot. (other employees will have access)
Exercises
Click on these links for practice on the comma.
- Commas (https://www.noslangues-ourlanguages.gc.ca/en/quiz/jeu-quiz-commas-1-eng)
- Commas, commas, and more commas (https://www.noslangues-ourlanguages.gc.ca/en/quiz/jeu-quiz-commas-4-eng)
- Coordinate your commas and conjunctions (https://www.noslangues-ourlanguages.gc.ca/en/quiz/jeu-quiz-coordinate-commas-eng)