Commas

Commas have three basic functions within a sentence:

  1. To SEPARATE less important clauses from the main part of your sentence
  2. To ENCLOSE nonessential information into manageable segments
  3. To LINK ideas that belong together

Rules may help you manage commas, but ultimately you have to develop a feel for them. Read sentences aloud and consider adding commas where you naturally pause. Use the following guidelines to help you decide:

I. Commas that SEPARATE:

  A sentence is made of a subject, verb, and predicate. Groups of words that do not fall into any of these categories are called phrases or clauses. Commas are often necessary to separate these clauses more clearly from the main structure of the sentence.

  1. To understand the appeal of city life, one should visit Boston or Chicago.

    2.   The comma sets off the introductory phrase, which is placed before the subject to tell when, where, how or why the main action of the sentence occurs.

  2. Although I hated carrots, I ate them for the carotene.

    3.   The comma separates the subordinate clause from the rest of the sentence. A subordinate clause is a group of words that cannot stand alone as a sentence, even though it has a subject and verb. These clauses often begin with words such as although, when, because, if, after, as, before, since, unless, or while.

  3. The orientation adviser urged us to be sensitive to our neighbors, implying that we might offend someone verbally.

    4. The comma is used to add an additional, nonessential thought to the end of the sentence.

  4. Playing golf is a luxury, not a necessity.

    5. The comma marks contrasts.

  5. He remarked, "Dinner was great." "That was the best meal I've ever eaten," he exclaimed to Mom.

    6. The comma separates the quote (which is a sentence by itself) from the main body of the sentence that contains it.

Caution:

  1. Don't use a comma to separate two complete sentences (comma splice).
    • Incorrect:That guy fell over a lot, he must have been drunk.
    • Correct:That guy fell over a lot; he must have been drunk.
  2. Don't use a comma to separate a subject from a verb.
    • Incorrect: Fighting for the championship, means playing hard.
    • Correct: Fighting for the championship means playing hard.

 

II. Commas that ENCLOSE:

  1. Neil Armstrong, who was born in a small Ohio town, was allegedly the first human to walk on the moon.

    2. The commas enclose the nonessential modifier, which adds information to a sentence but can be removed without altering the sentence’s basic meaning.

  2. Bob, a recent college graduate, was applying for a job as a teacher.

    3. The commas enclose the nonessential appositive, which is a noun or noun phrase that gives additional information about the subject.

  3. Nancy was, as her mother often said, very stubborn.

    4. The commas enclose phrases that interrupt the sentence. When the information given is not the main point of the sentence, you can use commas instead of parentheses.

Caution:

  1. Don't use commas to encluse information that affects sentence meaning.
    • Incorrect: Journalists, who claim dedication to community service, often have political agendas of their own.
    • Correct: Journalists who claim dedication to community service often have political agendas of their own.

 

III. Commas that LINK:

  1. She was going to go to sleep, but her friend called.

    2. The comma belongs before the conjunction (and, but, or, nor, for, yet, so) to link two complete sentences together.

  2. Mary was searching for her brother. Therefore, she was not home when her mom called.

    3. The comma links the transitional expression to the rest of the sentence. Transitional expressions include words (however, therefore, nonetheless, moreover, consequently, rather, otherwise, thus) and phrases (for example, as a matter of fact, in other words).

  3. George read a book, ate pizza, watched TV, and went to bed.

    4. The commas link three or more items in a series.

  4. Kelly is a smart, funny, kind friend.

    5. The comma appears between multiple adjectives to replace the word “and.”

Caution:

  1. Don't use a comma before a conjuction if the conjunction joins parts of the same sentence instead of two independent sentences.
    • Incorrect: I read the paper aloud, and discussed it with the student.
    • Correct: I read the paper aloud and discussed it with the student.

Additional Online Resources

UWC Handouts
Fragments and Run-ons

Virgil: Online Writing Tutorial
Commas

Purdue OWL
Commas
Run-ons- Comma Splices- Fused Sentences
Punctuation

AttachmentSize
Commas09pdf.pdf259.02 KB