Teacher’s Corner – Commas

The use of grammar is undervalued. Simply put, we are failing to give our students the proper tools to communicate effectively. To have a mastery of grammar is to know how sentences work, so you can express ideas more accurately. It helps us to structure ideas logically and to write with intent, thus helping our critical thinking skills. Ironically, a strong grasp of grammar also enhances the way we use AI. Knowing the rules allows us to craft better prompts and to revise AI-generated text effectively, using these tools as they were intended—a supplement, not a crutch. Currently, AI is far from infallible, and programs like Grammarly often misinterpret the intent of a sentence or the nuances of word choice.

For any teacher attempting to teach grammar, these are the seven rules for commas that I teach. I used the seventeenth edition of the Chicago Manual of Style to create these rules. There are certainly more rules and nuances students could learn, but this is more than enough for the average person who is not in a writing-intensive field. I often apply this to the real world and tell students that these are the only rules for commas you need to write a competent email. With enough practice, these seven rules are easy to remember and apply.

Rule 1: Use commas to separate three or more items in a series. (Serial Comma)

• We bought apples, oranges, and bananas at the market.
• The dog barked, spun in a circle, and sprinted toward the door.

Rule 2: Use a comma to show a pause after an introductory word or prepositional phrases at the beginning of a sentence.

• Before sunrise, the hikers set out on the trail.
• Unfortunately, the concert was canceled.

Rule 3: Use commas to set off words in a sentence that interrupt the flow of thought or provide an explanation (appositive phrase/ nonessential clauses).

• My brother, a talented guitarist, just released a new album.
• The book, which was first published in 1923, is still widely read today.
• Our teacher, despite her busy schedule, always makes time to help us.

Rule 4: Use commas to set off names used in direct address.

• Sarah, you will oversee transcribing the interview.
• Thank you, everyone, for coming.

Rule 5: Use a comma before, and, or, but when it joins a simple sentence into a compound sentence (FANBOYS).

• I wanted to go for a walk, but it started raining
• You can come with us, or you can stay home.

Rule 6: A dependent clause that precedes a main clause should be followed by a comma.

• Although the team was tired, they kept playing.
• If you need help, I’ll be in my office.

Rule 7: Use commas with items in dates and addresses.

• She was born on June 15, 2005, in Seattle.
• Send the letter to 125 Maple Street, Boston, Massachusetts, as soon as possible.

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