1. Separating Items in a Series:
- They separate items in a list, whether it's words, phrases, or clauses.
- Example: "I bought apples, oranges, and bananas."
2. Setting Off Interrupters:
- They isolate words, phrases, or clauses that interrupt the main flow of a sentence.
- These interrupters can be parentheticals, appositives, or non-essential clauses.
- Example: "The dog, a golden retriever, wagged its tail."
3. Marking Boundaries Between Clauses:
- They separate independent clauses (clauses that can stand alone as sentences) when joined by a coordinating conjunction (e.g., and, but, or, so, for, yet).
- They also separate independent clauses from dependent clauses when the dependent clause comes first.
- Example: "The sky was clear, but the wind was strong."
Understanding these three main functions will help you use commas correctly and effectively in your writing.