1. Joining two independent clauses:
* Use a comma before "but" when it connects two complete sentences.
* Example: The sun was shining, but it was cold outside.
2. Joining a dependent clause to an independent clause:
* Don't use a comma before "but" when it joins a dependent clause to an independent clause.
* Example: Although it was cold outside, the sun was shining. (No comma needed)
3. Joining two words or phrases:
* Don't use a comma before "but" when it joins two words or phrases.
* Example: He was tall but thin.
4. Starting a sentence:
* You can always start a sentence with "but."
* Example: But he was tired of waiting.
In summary:
* Use a comma before "but" when it joins two independent clauses.
* Don't use a comma before "but" when it joins a dependent clause to an independent clause or when it joins two words or phrases.
Let me know if you have any other punctuation questions!