C: Commas
C: commas. If your teacher marks "C" on your paper, do not merely add a comma; identify which of the comma rules below is applicable.
1. To separate independent clauses unless they are short:
COMMA NEEDED: His first wife tried to poison herself, and his second tried to poison him.
NO COMMA: Fish are jumping and the cotton is high.
If a comma is required, it belongs before, not after, a conjunction:
WRONG: She tried her hardest but, the bar was too high.
RIGHT: She tried her hardest, but the bar was too high.
2. After an introductory word group. A comma sets off a subordinate phrase or clause from the main clause. Use no comma if the phrase is short and there is no danger of misreading:
COMMA NEEDED: By the time the plane arrived, most of the babies had stopped crying.
NO COMMA: By now her plane must have arrived. In a democracy all votes are equal.
Often even short introductory phrases are momentarily ambiguous without commas:
MISLEADING: After eating Goldilocks takes a nap in the bears' bed.
CLEAR: After eating, Goldilocks takes a nap in the bears' bed.
3. With a series of three or more words. A comma is optional before the and or or, unless it is needed for clarity:
Aristotle classifies poetry as lyric, dramatic and narrative.
She sings, dances and acts.
4. Between coordinate adjectives:
WRONG: loud meaningless chatter
RIGHT: loud, meaningless chatter
Grammar TIp: Two kinds of adjectives require different punctuation. Commas separate only coordinate adjectives: adjectives that modify a noun or pronoun separately; that can be separated with and ("loud and meaningless chatter"); and that can be rearranged ("meaningless, loud chatter").
Do not use commas with cumulative adjectives: adjectives which do not modify the noun or pronoun separately and cannot be rearranged ("a large aquatic mammal").
COORDINATE: a long, frightening dream
CUMULATIVE: my usual bad dream
5. Before nonrestrictive elements. This rule is not as hard as it probably sounds. It merely tells you when to place a comma before which, who or whom:
NONRESTRICTIVE: Lions, which are mammals, eat meat. (referring to all lions)
RESTRICTIVE: Lions which have manes are male. (only certain lions)
"Nonrestrictive" just means you are not talking about all lions. If a sentence would still make sense without the clause, it needs commas. "Lions eat meat" is true, but "Lions are male" is not. A nonrestrictive element in the middle of a sentence requires commas before and after it:
WRONG: Her dad, who is sixty retired early.
RIGHT: Her dad, who is sixty, retired early.
Conversely, any comma before or after a restrictive element is wrong:
WRONG: The one on the far left, is my sister.
RIGHT: The one on the far left is my sister.
All clauses introduced with that are restrictive:
My brother attends the same school that I attend.
6. To set off appositives. An appositive is a noun phrase equivalent to another noun phrase in the sentence. If it comes in mid-sentence, it requires commas before and after it:
WRONG: Bob, my postman lives on my street.
RIGHT: Bob, my postman, lives on my street.
Appositives require commas only if they are nonrestrictive (see C5):
RESTRICTIVE: My classmate Ann plays the flute. (Ann is not your only classmate)
NONRESTRICTIVE: Our president, Ron, made a speech. (Ron is your only president)
7. To set off transitional phrases, wherever they are located:
However, cows moo. Cows, of course, moo. Cows moo, in fact.
8. Before and after interrupting phrases and clauses:
I wake up early, even on weekends, for a walk.
Her name, I think, is Ellen.
Do not confuse restrictive modifying phrases and clauses with interrupting phrases. The following sentences have no commas because the interrupting elements are restrictive:
I go walking in the park for exercise.
The girl I think is Ellen is on the left.
9. Before concluding elements. Use a comma before a concluding phrase or clause if it is not part of the main structure of the sentence and it is nonrestrictive (see C5):
He ran out the door, pausing to kiss his mother.
I like to run early, when it is still cool.
Careless comma placement can change the meaning of a sentence:
The boy sent a letter to the girl hoping for news. (the girl hopes for news)
The boy sent a letter to the girl, hoping for news. (the boy hopes for news)
10. To set off contrasts:
She wore blue, not white, at the wedding. At the wedding she wore blue, not white.
11. To set off absolute phrases:
His secret at last revealed, he abandoned all pretense.
The universe safe once more, Superman went looking for a phone booth.
Grammar TIp: An absolute phrase usually consists of a noun and a participial phrase. It modifies an entire sentence instead of a word or phrase.
12. With direct address. If the name comes in mid-sentence, use a comma before and after it:
Please, Superman, save our planet! Sit, Spot. Physician, heal thyself. Thank you, sir.
Writers of dialogue sometimes forget to include the comma:
WRONG: "Mary are you there?" I asked.
RIGHT: "Mary, are you there?" I asked.
13. Use commas with yes and no; use exclamation points or commas with interjections:
Yes, it is. No, sir. Hey! Well, have it your way. An error common in dialogue is omission of the comma:
WRONG: "Yes I am," she replied.
RIGHT: "Yes, I am," she replied.
If direct address interrupts, you may need two commas: No, Spot, I am not a fire hydrant.
14. To set off tag questions and similar phrases:
Today is Friday, isn't it?
It's only Tuesday, I fear.
A cup of coffee, please.
15. To set off dialogue. Phrases introducing quotations or dialogue require commas if they use verbs like says, asks, begs, insists and commands:
He explained triumphantly, "To get to the other side."
If the quotation comes first, a comma is still necessary unless a question mark or exclamation point closes the quotation:
"To get to the other side," he explained triumphantly.
"Why did the chicken cross the road?" he asked.
16. To prevent confusion. Even when no rule of punctuation requires one, a comma sometimes helps avoid confusing the reader (even if the confusion is momentary):
CONFUSING: A couple walked in hand in hand.
CLEAR: A couple walked in, hand in hand.
CONFUSING: What many people fear does not exist except in their minds.
CLEAR: What many people fear, does not exist except in their minds.
CONFUSING: a heavy hooded cloak
CLEAR: a heavy, hooded cloak or a heavy-hooded cloak
17. For conventional uses, including dates, numbers and titles:
June 16, 1904 5,280 Portland, ME John Smith, R.N. She stands five feet, four inches.
Add another comma after a date, address or title if the sentence continues:
Martin Luther King, Jr., was born on January 15, 1929, in Atlanta, Georgia, and educated at Morehouse College and Boston University.
C2nd: additional comma needed. If your teacher marks "C2nd," you have used one comma that requires you to add another comma elsewhere in the sentence.
Determine where the second comma belongs and add it. If you are not sure where it belongs, or you want to know why it is necessary, review the section on Commas, especially rules 5-8 and 10-12.