1. Separating Items in a List
* General Rule: Use commas to separate items in a list of three or more.
* Example: I need apples, oranges, bananas, and grapes.
* Final Comma (Oxford Comma): The comma before the "and" is optional. It's called the Oxford comma and can help avoid ambiguity in certain cases.
* Example with Oxford Comma: I need apples, oranges, bananas, and grapes.
* Example without Oxford Comma: I need apples, oranges, bananas and grapes.
2. Separating Independent Clauses
* General Rule: Use a comma before a coordinating conjunction (for, and, nor, but, or, yet, so) that joins two independent clauses (clauses that can stand alone as sentences).
* Example: The sun was shining, and the birds were singing.
3. Setting Off Introductory Phrases and Clauses
* General Rule: Use a comma after introductory phrases or clauses that precede the main clause.
* Example: After the long drive, we were exhausted.
* Example: Because I was tired, I went to bed early.
4. Setting Off Nonessential Phrases and Clauses
* General Rule: Use commas to set off words, phrases, or clauses that are not essential to the meaning of the sentence (nonessential or parenthetical elements).
* Example: My brother, who lives in California, is a doctor. (The clause "who lives in California" is nonessential).
* Note: You would not use commas if the phrase or clause is essential.
* Example: The doctor who lives in California is my brother. (The clause "who lives in California" is essential to identifying which doctor is being referred to).
5. Setting Off Interjections and Direct Address
* General Rule: Use commas to set off interjections (words that express strong emotion) and words used in direct address.
* Example: Oh, no! I forgot my keys.
* Example: John, can you please pass the salt?
6. Dates, Addresses, and Titles
* Dates: Use commas between the day and year and between the city and state.
* Example: June 15, 2023, was a beautiful day.
* Example: I live in Seattle, Washington.
* Addresses: Use commas after the street address, the city, and the state.
* Example: My address is 123 Main Street, Anytown, CA 12345.
* Titles: Use commas after a person's name followed by their title.
* Example: John Smith, President of the company, gave a speech.
7. Avoiding Comma Splices
* General Rule: Don't use a comma to separate two independent clauses unless they are joined by a coordinating conjunction. This is called a comma splice.
* Incorrect: I went to the store, I bought milk.
* Correct: I went to the store, and I bought milk.
8. Using Semicolons
* General Rule: Use a semicolon instead of a comma to separate two independent clauses that are closely related in meaning.
* Example: I went to the store; I needed milk.
Remember: These are general guidelines, and the specific rules for comma usage can sometimes be complex. It's always a good idea to consult a grammar guide or style manual if you have any questions.