Commas with Nonessential Elements
The Blue Book of Grammar and Punctuation
Commas with Nonessential Elements
Today, we’ll examine two more uses for the comma.
Rule 1: If something or someone is sufficiently identified, the description following it is considered nonessential and should be surrounded by commas.
Examples:
Freddy, who has a limp, was in an automobile accident.
(Freddy is named, so the description of him that immediately follows is not essential.)
The boy who has a limp was in an automobile accident.
(We do not know which boy is being referred to without having that further description; therefore, it is essential and no commas are used.)
Joanna Ferguson, a senior English major, is the best athlete in the school.
(Joanna is named, so the description that immediately follows is not essential.)
The crew members who work in our building are very friendly.
(We don’t know which crew members are being referred to without the description that follows, so no commas are used.)
Rule 2: Use the comma to separate two sentences if it will help avoid confusion.
Examples:
I chose the colors red and green, and blue was his first choice.
He will coach his younger son, and his older son will help tutor the children on the team.
Pop Quiz
Choose the sentence with the correct punctuation.
1A. Julie Andrews one of the most famous film stars in history starred in The Sound of Music.
1B. Julie Andrews, one of the most famous film stars in history, starred in The Sound of Music.
2A. I saw the girl with the red hair at the grocery store last night.
2B. I saw the girl, with the red hair, at the grocery store last night.
3A. Susan had to say the words slowly, and quickly he looked up to see she was crying.
3B. Susan had to say the words slowly and quickly he looked up to see she was crying.
Answers to Pop Quiz
Correct answers indicated by an asterisk (*).
1A. Julie Andrews one of the most famous film stars in history starred in The Sound of Music.
1B.* Julie Andrews, one of the most famous film stars in history, starred in The Sound of Music.
2A.* I saw the girl with the red hair at the grocery store last night.
2B. I saw the girl, with the red hair, at the grocery store last night.
3A.* Susan had to say the words slowly, and quickly he looked up to see she was crying.
3B. Susan had to say the words slowly and quickly he looked up to see she was crying.
If the article or the existing discussions do not address a thought or question you have on the subject, please use the "Comment" box at the bottom of this page.
Whatever happened to the rule about the placement of a comma after the words please and thank you?
We have not heard of any particular rule regarding the words “please” and “thank you.” Sentences containing these words should follow normal rules for placement of commas, such as our Rule 8: Use commas to set off expressions that interrupt sentence flow.
The following sentences, for instance, should not contain a comma:
Thank you for your consideration.
Would you please forward this email to your supervisor?
Please remember to wipe your feet before entering the building.
Here is one example where a comma would be used:
Thank you, Mr. Smith, for clarifying that point.
In the two examples you give under rule 2, aren’t these merely following the rule of joining two independent clauses by adding a comma and a coordinating conjunction (in this case “and”)?
For example: I chose the colors red and green, and blue was his first choice.
A) I chose the colors red and green.
B) Blue was his first choice.
Yes, the examples you cited demonstrate both Rule 2 in this blog and our Rule 3b of Commas: “In sentences where two independent clauses are joined by connectors such as and, or, but, etc., put a comma at the end of the first clause.”