Commas
The Comma [ , ]
1. Use a comma before the conjunctions and, but, for, or, yet, and nor when they join the clauses of a compound sentence. We inquired for him at the address she gave us, but no one there had ever heard of a person by that name. Note: Between most short clauses and between many long ones when the meaning is clear, the comma is omitted. First he stopped at the bank and then he went home.
2. Use a comma to separate an introductory clause or phrase from a main clause.
When he had tired of the mad pace of New York, he moved to Dubuque.
In the beginning, he liked the work.
Note: If the introductory clause or phrase is short, or if there is no danger of ambiguity, the comma may be omitted. The following examples require commas because their omission slows up comprehension.
In spite of all that, she got a passing grade.
If the police shoot, the woman may be wounded.
3. Use a comma to set off introductory yes and no, mild exclamations, words of direct address, and introductory words that serve as a transition (however, anyway, etc.)
Yes, I am going too.
Jane, bring the book with you.
Nevertheless, he was there when the trouble started.
4. Use a comma to set off a question at the end of a statement. You are coming too, aren't you?
5. Use a comma to set off dates, addresses, and titles.
The letter was dated June 20, 1973, and was sent airmail.
He lived at 21 Baker Street, Elyria, Ohio, for twenty years.
Dr. Mary Harris, Director of Admissions.
6. Use a comma to set off contrasted sentence elements. Fred, not Jim, was first in his class.
7. Use a comma to indicate an omitted word or words in parallel constructions within a sentence.
Irene is studying hard; Susan, scarcely at all.
8. Use a comma to set off sentence elements out of natural order.
That he would accept the money, none of us seriously doubted.
9. Use a comma to separate words, phrases, and clauses in a series.
The menu offered the usual choice of steak, chops, or chicken.
If he studies hard, if he takes good notes, and if he participates in class discussion, he will probably pass. Note: In the style of some individuals and publications, the final comma before the conjunction is omitted. The daffodils, hyacinths, tulips and lilacs were in bloom.
10. Use a comma to set off absolute and parenthetical elements in the sentence.
We finished within the allotted time, however.
He did not say that, as you will realize when we play the recording, but he did imply it.
11. Use a comma to separate coordinate adjectives modifying the same noun. (If you can substitute and for the comma, the adjectives are coordinate.)
It was a quaint, old-fashioned, vine-covered cottage. She had bright, mischievous, laughing brown eyes. But do not use a comma to separate non-coordinate adjectives modifying the same noun. Professor Jones is a kind old gentleman.
12. Use a comma or commas to set off nonrestrictive phrases or clauses from the rest of the sentence. (A nonrestrictive phrase or clause is one not essential to the meaning of the sentence.)
My gun, which is now over the mantlepiece, hasn't been used for years.
He found the paper on the roof, where the newsboy had thrown it.
13. Use a comma to set off direct quotations from such expressions as he said, she replied, etc.
He said, "I'll never believe you again." "I know you can pass this course," he said, "if you will only try."
But note: If the he said (or similar expression) comes between two independent clauses, then it must be followed by a period or semicolon, not by a comma.
"Try this book," he said. "I think you will like it."14. Use a comma following the salutation of a personal letter and following the closing phrase of every letter.
Dear Jean,
Very truly yours,
15. Use a comma before and after a dependent clause that comes in the middle of a sentence.
The apples, although they had been freshly picked, became spoiled in shipment.
16. Use a comma after terms (e.g., i.e., namely) that introduce a series or an example.
Some of our presidents, e.g., Jefferson, J. Q. Adams, and Buchanan, had previously been secretaries of state. But note: "Such as" should not have a comma preceding or following it.
I enjoy sports such as football, basketball, and track.
17. Use a comma to set off the one spoken to in direct address.
"John, you're the troublemaker in this class."
"Yes, sir, I guess I am."
18. Use a comma to separate thousands in numbers of one thousand or over.
The area of the earth is approximately 196,950,000 sq. mi.
19. Use a comma to separate inverted names, phrases, etc., as in a bibliography, index, or catalogue.
Jones, Harold T.
Persia, architecture of
radios, portable
20. In a typed manuscript a comma is followed by one space.
Misused and Unnecessary Commas
1. Do not use a comma to separate independent clauses not joined by a conjunction. This error is called the comma splice or comma fault.
Evanston is by no means a resort city; however, its recreation facilities are of the finest. (not ... a resort city, however, . . .)
John told me he was an officer in the army; that isn't what I heard from others, however. (not... in the army, that isn't what . . .)
2. Do not use a comma or commas to set off restrictive phrases or clauses—that is, phrases or clauses necessary to the proper identification of the words they modify.
The book which I am reading is a history text.
3. Do not use a comma to separate a verb from a noun clause used as its subject or as its object.
That the professor enjoyed his subject was evident. (not That the professor enjoyed his subject, was evident.)
I cannot imagine what made me do it. (not I cannot imagine, what made me do it.)
4. Do not use a comma between a noun and an adjective that comes directly before it.
It was a cold, wet, miserable day. (not . . . a cold, wet, miserable, day.)
5. Do not use a comma before that introducing an indirect statement.
He said that he would be there. (not He said, that he would be there.)