1. Separating Items in a List:
* When three or more items are listed:
* "I need to buy milk, eggs, bread, and cheese."
* Before the conjunction "and" when there are four or more items:
* "She packed her suitcase with clothes, toiletries, books, and a first-aid kit."
2. Separating Independent Clauses:
* When two complete sentences (independent clauses) are joined by a coordinating conjunction (for, and, nor, but, or, yet, so):
* "The sun was shining, and the birds were singing."
* If no conjunction is used, a semicolon is needed:
* "The sun was shining; the birds were singing."
3. Setting Off Introductory Phrases and Clauses:
* After a short introductory phrase:
* "In the morning, I like to drink coffee."
* After a longer introductory clause:
* "Because it was a beautiful day, we decided to go for a hike."
4. Setting Off Non-Essential Phrases and Clauses:
* Phrases or clauses that add extra information but are not crucial to the main sentence:
* "My brother, who is a doctor, lives in New York."
* Use commas before and after the phrase or clause:
* "The book, which I read last night, was very interesting."
5. Setting Off Appositives:
* Words or phrases that rename or explain a noun:
* "My dog, a golden retriever, loves to play fetch."
6. Separating Adjectives:
* When adjectives are used to modify the same noun and can be reversed without changing the meaning:
* "She wore a beautiful, red dress."
7. In Dates, Addresses, and Numbers:
* Dates: "July 4, 1776"
* Addresses: "123 Main Street, Anytown, CA 12345"
* Large numbers: "1,000,000"
8. In Direct Quotes:
* To separate the quote from the speaker:
* "I'm going to the store," she said.
9. To Indicate a Pause:
* Sometimes used for emphasis or to create a specific rhythm:
* "Well, I never!"
10. To Prevent Misreading:
* Avoid confusion by separating words that might otherwise be misread:
* "Please, let me know if you have any questions." (vs. "Please let me know if you have any questions.")
Remember: Comma rules can be complex, and there are exceptions. If you're unsure about comma usage, consult a style guide or grammar resource.