Comma Get It!

Robots love commas

Robots love commas.

Commas aren’t some piece of punctuation meant to aggravate you. They can actually be used as rhetorical tools, meaning that you can use them to emphasize information. Commas can also help you add clarity to your writing so you don’t confuse your readers.

Commas separate, introduce, and show information. While comma rules aren’t completely rigid, there are some comma guidelines that you should be familiar with. Once you get to know these, you can begin to mess with them to suit your rhetorical needs.


There are four cases when you should really use commas:

1. To separate clausesCommas often separate an independent clause (a phrase that can stand alone as a sentence) from a dependent clause (a phrase that can’t stand alone).

  • When the robot was first built, he didn’t have any legs.

2. To separate parenthetical phrases. Parenthetical phrases interrupt other phrases or clauses, and contain extra information that could be removed from the sentence without changing the sentence’s core meaning.

  • The robot, which had no name, was created to guard and protect the Writing Center.

3. To separate introductory phrases. An introductory phrase is a phrase at the beginning of the sentence (usually a dependent clause) that provides background information for the main sentence.

  • While the robot was painted silver, he had a heart of gold.

4. To balance two independent clauses (with a coordinating conjunction). Two independent clauses can be two separate sentences, or can be combined into one sentence using a comma and a coordinating conjunction (and, but, or, yet, for, nor, so).

  • Students loved the robot, for he was kind and generous.
  • The robot enjoyed getting to see the students, but he was always sad when the Writing Center closed for the night.
  • The tutors realized how lonely the robot was becoming, so they built him a robot dog to keep him company.


Even though there is a lot of flexibility in what ways you can use commas, there are also cases when you should avoid using them:

1. Don’t separate the verb from its subject or its object.

  • The robot, danced when no one was looking. → The robot danced when no one was looking. (The robot is the subject, danced is the verb.)
  • The robot walked, his robot dog. → The robot walked his robot dog. (Walked is the verb, his robot dog is the object.)

2. Don’t use a comma between an adjective and a noun.

  • The cardboard, robot was always eager to help students with their writing. → The cardboard robot was always eager to help students with their writing.

3. Don’t use a comma before the first item in a series.

  • The robot likes, gummy worms, break dancing, and paper cranes. → The robot likes gummy worms, break dancing, and paper cranes.

4. Don’t use a comma after a coordinating conjunction.

  • The robot was large yet, gentle. → The robot was large yet gentle. *OR* The robot was large, yet gentle.

Note: You can use a comma before the coordinating conjunction if you want, but you don’t have to, since the two clauses are not independent clauses. Whether or not you put a comma before the coordinating conjunction in cases like this will depend on how much you want to emphasize the piece after the conjunction.

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We hope this rundown of good and not-so-good uses of commas is helpful for you. If you have any more punctuation questions, feel free to stop by the Writing Center or schedule an appointment here.

We also hope that you’ll stop by and check out our new giant cardboard robot—he still needs a name and we would love your input!

Annie and Sarah, peer tutors

Fan Fiction and Grammar Tips

Some students come into an appointment at the Writing Center asking if we will edit their paper.

The short answer is not exactly!

The long answer is yes—and we’ll show you how to look for grammatical mistakes, so that you can have the tools to do so yourself.

We want you to become a better writer and not just have a better paper.

So let’s take this really badly written and grammatically incorrect piece of fan fiction I just wrote this morning after too much soda and too little sleep.

I’ll make this fan fiction about Harry Potter:

Harry woke up in a wave of tears. He dreams about Hermione last night and how Ron took her away from him. Angrily, he ran over to his mirrors in his room on Private drive and punched it. Harry did not want to look at himself.

“It should be I who has Hermione as a girlfriend, not Ron!” said Harry.

Harry walked around his room he thought of the many ways he could seek revenge on his freckled enemy, he would need his wand and the help of his most hated arch-nemeses Draco Malfoy.

Boy, I’m sorry you had to read through that. Trust me. It was just as much torture to write it. Here’s a picture of a kitten to pick you up:

Courtesy of

Now of course this is an extreme case, but the same rules apply. If I brought this fanfiction to the Writing Center to be worked on, they would focus on teaching me better ways to identify and fix grammatical mistakes.

Let’s start from the top.

The first error is a tense agreement error: “He dreams about Hermione last night and how Ron took . . . .” Each verb tense must be the same, either past or present. To fix it, “dreams” should be changed to dreamt or dreamed. The best way to identify this mistake and fix it yourself is to read through your paper with a consistent tense in mind. If your objective is past tense, go through each verb and make sure it is the past tense of it. If it is present, make sure every verb is present.

The second error is a pronoun disagreement: “he ran over to his mirrors . . . and punched it.” Each pronoun should agree in a sentence; they should be either singular or plural respectively. Thus, “mirrors” should be changed to mirror or “it” to them. The best way to identify and fix this grammatical mistake is to read your paper aloud. If you read it aloud, you’ll notice that the flow of your reading is interrupted by pronoun disagreement.

The last error is the run-on sentence (sentence that “runs on” without proper punctuation). The last paragraph of the fan fiction is all one sentence. Sometimes this can happen, but not if it is grammatically incorrect and without proper punctuation. Let’s fix this: “Harry walked around his room. He thought of the many ways he could seek revenge on his freckled enemy; he would need his wand and the help of his most hated arch-nemeses, Draco Malfoy.” The best way to identify such a grammatical mistake is to reread sections with long sentences especially. Sometimes you write in stream-of-consciousness, forgetting to punctuate.

Here is a handout about commas, periods, semicolons, and colons.

With all that said, grammar can be hard sometimes. We all make mistakes, but if you make yourself more self-aware of your writing, it will make you a better writer.

For help with these challenges—or any others–come visit us at the Writing Center in Hill Hall room 111 or book an appointment with us!

Oh and if you want to talk about kittens, that’s cool too.

Courtesy of

Charles, peer tutor.