Use commas to separate items in a series—words, groups of words, phrases, and short independent clauses—unless the items are separated by conjunctions.
Use a comma to separate two or more adjectives that come before a noun.
Use a comma after certain introductory elements.
(1) Use a comma after an introductory participial phrase.
- Living in Dallas, most residents will experience road rage.
(2) Use a comma after two or more introductory prepositional phrases.
- After the final on Tuesday, we can relax for a week.
(3) Use a comma after an introductory adverb clause.
- If it rains today, the baseball game will be cancelled
Use commas to set off expressions that interrupt the sentence.
(1) Appositives and appositive phrases are usually set off by commas.
- Tina’s father, Jerry Smith, works at the planetarium.
(2) Words used in direct address are set off by commas.
- I hope, Lisa, that you’re going to show up for class today.
(3) Parenthetical expressions are set off by commas.
- The teacher was, of course, serious about the test scores.
(4) Words such as well, yes, no, and why are followed by a comma when they begin a sentence or remark.
- Yes, copies are in the office.
- Well, he did say he’d be here
Use commas to set off nonessential clauses and nonessential participial phrases.
Use a comma before and, but, or, for, so, nor, and yet when they join independent clauses in a compound sentence.
Use a comma in certain conventional situations.
(1) Use commas to separate items in dates and addresses.
- January 14, 2005
- 12345 South Second Street, Anyplace, Texas
(2) Use a comma after the salutation of a friendly letter and after the closing of any letter.
- Dear Bob,
(3) Use a comma with direct quotations.
- One teacher told me, “You should always attend class.