Understanding clauses is important to using commas correctly because
commas are used according to the type and structure of the clause.
Clauses
A clause is a group of words with both a subject and a predicate. There are two types of clauses.
A. Independent Clause: A group of related words that can stand alone as a complete
sentence.
sub. pred.
She was unhappy with her grade.
B. Dependent Clause: Cannot stand alone as a complete sentence because of the word
introducing it:
sub. pred.
She is the best performer when she gets enough sleep.
sub.
pred.
What the witness said may be a lie.
Comma Rules with Phrases and Clauses
Commas are needed in the following situations:
A. Before a coordinating conjunction linking independent clauses.
Subject + predicate,
conjunction subject + predicate.
Jane
went to the store, but
she
forgot her money.
(The conjunction is like a glue word; it connects words, phrases, and clauses.)
B. After introductory words, phrases, or clauses.
Introductory word:
However, Jane had her checkbook.
Introductory phrase:
In the produce aisle, Jane saw Robert.
Introductory clause:
Although Robert seems like a trouble maker, Jane has a crush on him.
C. Separating elements in a series that contains three or more parallel elements.
Robert drinks, swears, and parties too much.
D. Set off nonessential elements (information not needed to understand the meaning of a
sentence).
The department Christmas party, at Jane’s house, will be a blast.
(In this example, we do not need to know where the party is to know
which party the speaker is talking about.)
COMPARED TO
The party at Jane’s house will be a blast.
For further explanation on comma rules, see the Writer’s Harbrace Handbook (Loretta Gray and Glenn Cheryl):
pp.683-696.
For more resources:
www.cwu.edu/~writingcenter/