Proper Comma Usage
Good business writing is the textual equivalent of a well-made, perfectly tailored suit. People who write well sound smart, confident, and successful. And yet, so much business writing is simply bad—the textual equivalent of frumpy pajamas. Let’s start with the abused, misused, and neglected comma.
Proper Comma Usage in Simple Sentences
What it is: A simple sentence has a subject and a predicate with one or more main verbs. (A simple sentence is also known as an independent clause.) A main verb is a verb that describes the primary action of the subject in the sentence. For example, “the falling London Bridge” is not a simple sentence because there is no main action. The bridge is falling, but “falling” is used as an adjective to describe the London Bridge, not a verb.
Simple sentence #1: Humpty Dumpty sat on a wall. (subject: Humpty Dumpty; main verb: sat)
Simple sentence #2: Humpty Dumpty sat on a wall and had a great fall. (subject: Humpty Dumpty; main verbs: sat, had)
Simple sentence #3: All the king’s horses and all the king’s men couldn’t put Humpty together again. (subject: All the king’s horses and all the king’s men; main verb: put)
With simple sentences that have only one main verb, such as “Humpty Dumpty sat on a wall,” it’s pretty clear that a comma anywhere in the sentence doesn’t make sense:
Humpty Dumpty sat on a wall.
But what about a simple sentence with two main verbs? Don’t use a comma:
Humpty Dumpty sat on a wall and had a great fall.
Resist the temptation to insert a comma between “wall” and “and.” Because “had a great fall” is not itself a complete sentence, inserting a comma is incorrect comma usage:
Humpty Dumpty sat on a wall, and had a great fall.
Proper Comma Usage in Compound Sentences
What it is: A compound sentence contains two or more simple sentences—each with a subject and a main verb.
Simple sentence #1: Jack fell down and broke his crown.
Simple sentence #2: Jill came tumbling after.
Compound sentence: Jack fell down and broke his crown, and Jill came tumbling after.
When connecting two simple sentences, you should use a comma with a conjunction (and, or, but, etc.):
Jack fell down and broke his crown, and Jill came tumbling after.
If you choose to omit the conjunction, you need to remove the conjunction and replace the comma with a semi-colon:
Jack fell down and broke his crown; Jill came tumbling after.
Or, you could simply make the compound sentence two simple sentences:
Jack fell down and broke his crown. Jill came tumbling after.
Employing a comma alone, without a conjunction, turns the compound sentence into a grammatically incorrect comma splice:
Jack fell down and broke his crown, Jill came tumbling after.
Proper Comma Usage with Complex Sentences
What it is: A complex sentence has one independent clause with one or more dependent clauses. An independent clause is a simple sentence with a subject and a main verb. A dependent clause contains a subject and a verb but cannot stand alone as a sentence.
Independent clause: The cradle will rock.
Dependent clause: When the wind blows (Note: not a complete sentence!)
Complex sentence: When the wind blows, the cradle will rock.
When the dependent clause precedes the independent clause, use a comma to mark the end of the dependent clause:
When the wind blows, the cradle will rock.
When the independent clause precedes the dependent clause, no comma is necessary:
The cradle will rock when the wind blows.
Employing a comma after the independent clause creates an unnecessary and unnatural pause and is incorrect comma usage:
The cradle will rock, when the wind blows.
To strengthen your business writing, check out our online business writing courses: Writing Effective Business E-mails and Writing the Modern Memo. (Try our courses for free with promo code OHCBLOG.) You can also download ten tips for writing effective business e-mails.
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Julie H.
One Hour Courses
www.onehourcourses.com
Thank you for all the great posts from last year! I look forward to reading your blog, because they are always full of information that I can put to use. Thank you again, and God bless you in 2010.