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Comma Practice


  1. Write more “natural-sounding” English by learning to use commas more accurately.
  2. Communicate in writing more effectively through better sentence structure


  1. Read the rules on using commas.
  2. Try the exercise

1. Rules for When to Use Commas

  1. Two independent clauses
  • Use a comma between two independent clauses joined by a coordinating conjunction such as and, but, or, and nor.
  • Independent clause = a sentence
  • Examples:
    • This is not correct: I like torts, and I like civil procedure. (I like torts. + and + I like civil procedure.)
      • No comma: “I like torts and civil procedure.” No comma is needed because “civil procedure” is not an independent clause.
    • This is also not correct: He went to the store, but left.
      • No comma: “He went to the store but left.” No comma is needed because “but left” is not an independent clause.
    • This sentence is correct: He went to the store, but the store was closed.
  1. Series
  • Use commas to separate three or more items (words, phrases, or short clauses) in a series. For clarity, be sure to use a comma before the conjunction.
  • Examples:
    • I like A, B, C, D, E, and F.
    • I like torts, civil procedure, and contract law.
    • She always takes notes, reorganizes them after class, and then studies them on the weekend.
    • The judge preferred listening to both sides, writing her thoughts down, and then making a decision.
  1. Introductory phrases
    1. Use commas after introductory phrases.
    2. Note: The general rule is 5 words or more. But actual use varies.
    3. Examples:
      1. However, the defendant argued against the motion.
      2. Therefore, the judge will likely find for the plaintiff.
      3. For the purpose of fairness, we will give both parties equal time to argue.
      4. Even though the defendant made a strong argument to the judge, she still was found guilty.
      5. While some people are in favor of strong environmental laws, other people prefer looser regulation.
      6. To apply for a job, submit an application to Mr. Smith.
      7. If the plaintiff was partly responsible, then the defendant will not be liable.
      8. When the police arrived, the lawyer introduced herself.
      9. Regarding Section 3 of the contract, we would like to suggest some changes.
      10. Because the coffee was extremely hot, the jury felt that McDonald’s was liable.
      11. For example, yesterday Starbucks was closed.
  1. Interrupters
  • Use commas to separate internal sentence interrupters, such as non-restrictive (non-essential) clauses. 
  • These are clauses that add information that describes the noun that comes right before the clause.
  • For example:
    • On Monday, which is a holiday, we will close.
    • Barack Obama, the 44th President of the United States, is coming over for dinner tonight.
    • My brother, who is an experienced lawyer, is helping me with my first client case.
    • I went to the store, which is two blocks away. 
  1. Proper form
  • Use commas in:
    • dates
      • Today is Tuesday, May 31, 2017
    • addresses
      • Queens, NY 11439
    • long numbers
      • 1,359,542,113

2. Try the exercise