| A | B |
|---|
| Rule #1 | after introductory words or phrases |
| Rule #2 | after adverbs that introduce a series |
| Rule #3 | after every item in a series |
| Rule #4 | after every item in a date |
| Rule #5 | after every item in an address |
| Rule #6 | after greetings and closings in a friendly letter |
| Rule #7 | between adjectives that describe the same noun |
| Rule #8 | set off direct address |
| Rule #9 | set off appositives |
| Rule #10 | set off nonrestrictive clauses |
| Rule #11 | set off interrupters |
| Rule #12 | before the conjunction in a compound sentence |
| Rule #13 | with participial phrases |
| Rule #14 | with explanatory words in quotes |
| Rule #15 | to avoid confusion |
