Writing Resources

End Stop Punctuation, Fragments, and Commas

This handout is available for download in DOCX format and PDF format.

End Stop Punctuation

When you reach the end of a sentence, you need a period, question mark, or exclamation point.


Use a period after a sentence that makes a statement or a request. Make sure that your statements have an independent clause (see handout on independent clauses).


Phrases or subordinate clauses standing alone are missing a subject or a verb or are stated in such a way that they cannot stand alone. Fragments can be useful in informal conversations, but they have no place in formal writing.

Examples of grammatical sentences:

  • The pivotal event in the Civil War was the Battle of Gettysburg.
  • Study your punctuation.

Examples of fragments:

  • After having gone swimming.
  • Went to the store.
  • Before eating dinner and going to bed.

Examples of corrected fragments:

  • After having gone swimming, Jake took a nap.
  • John went to the store.
  • Bob practiced the guitar before eating dinner and going to bed.

Nine Rules for Commas

1. Independent clauses are separated by a coordinating conjunction.

  1. You can remember these conjunctions with the mnemonic FANBOYS; For, And, Nor, But, Or, Yet, and So receive a comma.
  2. A comma placed between two independent clauses that are not joined by a FANBOYS creates a comma splice, an ugly grammatical mistake. Be sure to include a FANBOYS as well as a comma.
  • I found a shiny rock, I brought it home. (INCORRECT! COMMA SPLICE!)
  • The table is set, and the dinner is ready.
  • Greg wanted to go to a movie, but Janice did not.

2. Introductory subordinate clauses and prepositional phrases receive commas.

Examples of subordinate clauses and prepositional phrases:
  • In the great big state of Texas, farmers are now growing grapes.
  • After she had given him a book, she asked him to read aloud.
  • Before eating dinner and going to bed, I went for a run.

3. Items in a series receive commas.

Example of items in a series:
  • I bought eggs, butter, cheese, milk, and bread.

4. Serial comma

Grammarians disagree over whether a comma should be placed before the conjunction in a series (the underlined comma in example 2 below is a “serial comma”). However, confusion can be avoided by adding such a comma:

  • “I want to thank my parents, Sue and Bob” is different from “I want to thank my parents, Sue, and Bob.” In (1) my parents are Sue and Bob. In (2) I thank my parents, and I thank Sue, and I thank Bob.

5. Multiple adjectives in a series are separated by commas, but commas are not used to separate adverbs and adjectives.

Examples of adjectives and adverbs:
  • I liked the beautiful, sparkling vase.
  • I liked the very beautiful, sparkling vase. (no comma between very and beautiful)

6. Parenthetical elements (phrases and clauses) and interrupters receive commas when parentheses are not used.

Examples of interrupters and parenthetical elements:
  • I will buy, I think, a new dress.
  • The criminal, we all believe, is guilty.
  • He thought (though it was untrue) that we wanted him as boss.

7. Direct addresses—people or objects to which you are directly talking—are set off by commas.

  • Mitch, eat your vegetables.
  • Brilliant scholar, would you publish in our journal?

8. Speech tags are separated from quoted speech by commas. Do not use a comma when the word “that” is present.

Examples of speech tags:
  • He said, “Hi!”
  • The critic argued that “Hamlet has been given a disproportionate amount of attention.”

9. Appositives, phrases which restate a noun, are set off by commas.

Examples of appositives:
  • Clinton, the 42nd president, started a foundation.
  • Bill Gates, a Harvard drop-out, gives huge amounts of money to AIDS research.

Credit: Lydia Fash, © 2008, 2009