In the writing classes I teach at the college, I assign a comma exercise. I provide students fifteen sentences and instructions to add commas in the appropriate place, provide the reason for the comma, or mark the sentence with a C if it is correct (no commas needed).
The textbook I use contains a glossary with the most common reasons for commas, and I encourage students to use the appendix.
For most students, this is one of the hardest assignments of the semester. Sentences without punctuation are difficult to read. Knowing where to insert a comma is tough, but knowing why is even more difficult.
Here are some common reasons to use commas.
- Insert comma between two independent clauses joined with a conjunction. Example: Louise thought John would be late, but John made it on time.
- Use commas between three or more items in a series. Example: Larry, Moe, and Curly. NOTE: Some writing manuals require the comma before the conjunction in a series (Chicago Manual of Style and APA, for example), while others do not.
- Use a comma after introductory phrases. Example: When the sun goes down, the night creatures come out.
- Use a comma to set off contrasting words or phrases. Example: The more you edit, the better your writing.
- Use commas for sentence interrupters. Example: She is, or thinks she is, a wonderful person.
- Use commas to set off explanatory equivalents. Example: My mother, Jane, is a huge baseball fan.
- Use a comma in a direct address. Example: Mary, can you babysit Saturday night?
- Use commas with direct quotations. Example: Tom said, “I’m trying out for the lead in the class play.”
- Use commas between modifiers. Example: the thorough, concise, readable manuscript.
Make sure you have a reason for inserting a comma (and the reason is not “That’s where I stop to take a breath.”). Your comma sense will show and you won’t go comma-crazy.