Commas
Rule # 1 – Use commas to separate items in a series of three or more different items. Use one comma fewer than the number of items. Do not use a commas to join two sentence parts: two verbs, two subjects, etc.)
§ I bought cheese, donuts, and milk at the store. (2 commas, 3 items)
§ Your recommendation states that you are a dynamic, creative, energetic, and responsible young woman. (3 commas, 4 items)
Rule # 2 – Use commas to separate coordinate adjectives modifying the same noun; a commas is appropriate if the word and made sense between the adjectives.
o “She is a creative, intelligent woman” (and fits between)
o “It was a bright red hat.” (and does not fit)
NOTE: a comma is appropriate if the word and makes sense between the adjectives.
Rule # 3 – Use a comma before and, but, or, nor for , so, and yet to join two independent clauses.
o I want to go to the Iowa game, but I have too much homework.
o I'm a Cubs fan, yet I'd love to go to a World Series game!
Rule # 4 –.Use a comma to set off nonessential clauses and phrases in a sentence.
essential info “Carlos Harris is the only senior who plans on attending Vassar this fall.”
nonessential info “Carlos Harris, who was offered an academic scholarship, will attend Vassar.”
essential info “Pierre is the city that I will research for my report..”
nonessential info “Pierre, which is the capital of South Dakota, is located on Lake Sharpe.”
Rule # 5 – Use a comma after an introductory injection - well, yes, no.
· Well, I suppose I'd be happy for the Sox if they win the World Series.
Rule # 6 – Use a comma after an introductory participial phrase.
· “Giggling loudly, she turned red.”
but not a gerund subject - “Giggling loudly is prohibited in class.”
Note: Use a comma if you could start the sentence without the beginning phrase. If not, don't use a comma.
Rule #7: Use a comma after a series of prepositional phrases.
Ø After school and before football practice, I like to see my girlfriend.
ü Because two prepositional phrases are used in a series ("After school" and "before football practice) a comma is needed. Using only one of these prepositional phrases would eliminate the need for a comma.
Rule #8: Use a comma after an introductory adverbial phrase.
When Steve studies his literature, he does much better.
ü The adverbial phrase is "When Steve studies his literature." A comma is needed following this phrase.
Rule #9: Use a comma to set off appositives.
Ø An interview with Ron Santo, a Chicago Cubs commentator and legend, was published in the Chicago Tribune.
ü Appositives are phrases which follow nouns and rename and further explain them.
ü The appositive phrase "a Chicago Cubs commentator and legend" renames and further describes Ron Santo.
Rule #10: Use commas to set off titles and names of direct address.
Ø Doctor, did you know that the medical shipment is late?
ü The above statement places emphasis on "Doctor," thus a comma is needed after this direct address.
Rule #11: Use commas to set off parenthetical expressions.
Ø Steve, I’m sure, will go to a better hair stylist next month.
ü A parenthetical expression explains or qualifies a statement.
ü The expression "I'm sure" qualifies the statement in the above sentence.
Rule #12: Use commas after each item of a date or address when there are two or more items.
Ø Mr. Janota was married on Saturday, July 23, 2005.
ü An item is commonly understood to be month and date or state and zip code.
Rule #13: Use commas to make certain the reader does not confuse the meaning of a sentence.
Ø After eating, my family watched television.
Without a comma the above sentence would cause confusion and likely result in a misread.