Comma Overuse

Learning Objectives

  • Recognize the standard uses of commas

Commas with Introductory Words or Phrases

An introductory phrase is a group of words at the beginning of a sentence that provides background information or sets the stage for the main part of the sentence. Since an introductory phrase can be removed without changing the core meaning of the sentence, a comma helps clarify that it is an extra part of the sentence.

Sometimes, an introductory phrase is just one word. In these cases, a comma is still needed. Some common words that begin introductory phrases include:

  • Because
  • Although
  • After
  • While
  • Nevertheless
  • Therefore
  • Since

Each of these words introduces a dependent clause or transition, requiring a comma before the main part of the sentence.

One way to identify an introductory phrase is to see if it can be moved to the end of the sentence without changing the meaning.

Example: Introductory phrases

  • Because I ate food, I was not hungry. (Introductory phrase at the beginning)
  • I was not hungry because I ate food. (Same phrase at the end—no longer introductory)

Key Takeaway: Introductory phrases

When an introductory phrase appears at the beginning of a sentence, it should be followed by a comma. However, when the same phrase appears at the end, a comma is not needed.

Common Comma Mistakes

Placing a Comma Between the Subject and the Verb

A comma should not separate the subject of a sentence from its verb.

Examples: Incorrectly separating Subject and Verb

Incorrect:

  • My mother, is a wonderful cook.
  • The judge, jury, and audience, were all surprised by this admission.

Correct:

  • My mother is a wonderful cook.
  • The judge, jury, and audience were all surprised by this admission.

Using a Comma Between Compound Subjects or Verbs

A compound subject consists of two or more subjects joined by and or or. A compound verb consists of two or more verbs describing the same subject. Commas should not be placed between them.

Examples: separating compound Subjects and Verb

Incorrect:

  • My brother, and my sister both hate broccoli with a passion.
  • Jesse tripped, and fell into a rosebush.

Correct:

  • My brother and my sister both hate broccoli with a passion.
  • Jesse tripped and fell into a rosebush.

Using a Comma Before a Preposition

Prepositions (such as in, on, at, with, to, through) show relationships between words in a sentence. A comma should not separate a preposition from the rest of the sentence.

Examples: Commas before a Preposition

Incorrect:

  • I signaled quietly to Harriet that she had spinach, in her teeth.
  • All Juan wanted to do was to have some time outside walking, through the forest.

Correct:

  • I signaled quietly to Harriet that she had spinach in her teeth.
  • All Juan wanted to do was to have some time outside walking through the forest.

Placing a Comma Before or After a Conjunction

A conjunction (such as and, but, or, so, yet) should not have a comma before or after it unless it separates two independent clauses.

Examples: Commas after a conjunction

Incorrect:

  • I challenged Mr. Burton to an arm-wrestling match and, he beat me twice.
  • Joey tossed the ball, and watched his dog run after it.

Correct:

  • I challenged Mr. Burton to an arm-wrestling match, and he beat me twice. (Correct because both clauses are independent)
  • Joey tossed the ball and watched his dog run after it. (No comma needed because watched his dog run after it is not an independent clause)

Using a Comma Before a List

A comma should not be placed before listing items unless there is an introductory phrase or it is part of a necessary sentence structure.

Example: Commas before lists

Incorrect:

  • My favorite things to eat for breakfast are, bacon, eggs, and cereal.

Correct:

  • My favorite things to eat for breakfast are bacon, eggs, and cereal.

Try It

Commas with Adjectives

This is an easy and simple rule! Or, this is an easy, simple rule. When you have two adjectives modifying a noun (easy and simple are the adjectives) describing the noun (rule), you use a comma between the two. You can double check this by substituting the word “and.” If “and” works, the comma is correct.

Examples: Commas with adjectives, the “And” Test

  • It was a dark and stormy night.
  • It was a dark, stormy night.

Should we use a comma here?

  • Tom got Huck to paint the white picket fence.
  • Tom got Huck to paint the white and picket fence. That sounds weird. So we don’t use a comma between white and picket. 

One way to think about this rule is that the two adjectives need to be equal; the other way is just to use the “and” test.

Try It

Complete the practice exercises in the interactive below to ensure you know when to use, and when not to use, a comma.