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Using Commas, Semicolons, and Colons Within Sentences

Punctuation within sentences can be tricky; however, if you know just a few of the following rules, you will be well on your way to becoming a polished writer and proofreader.

Rule: Use a comma between two long independent clauses when conjunctions such as and, or, but, for, nor connect them.
Example: I have painted the entire house, but she is still working on sanding the floors.

Rule: If the clauses are both short, you may omit the comma.
Example: I painted and he sanded.

Rule: If you have only one clause (one subject and verb pair), you won’t usually need a comma in front of the conjunction.
Example: I have painted the house but still need to sand the floors.
This sentence has two verbs but only one subject, so it has only one clause.

Rule: Use the semicolon if you have two independent clauses connected without a conjunction.
Example: I have painted the house; I still need to sand the floors.

Rule: Also use the semicolon when you already have commas within a sentence for smaller separations, and you need the semicolon to show bigger separations.
Example: We had a reunion with family from Salt Lake City, Utah; Los Angeles, California; and Albany, New York.

Rule: A colon is used to introduce a second sentence that clarifies the first sentence.
Example: We have set this restriction: do your homework before watching television.
Notice that the first word of the second sentence is not capitalized. If, however, you have additional sentences following the sentence with the colon and they explain the sentence prior to the colon, capitalize the first word of all the sentences following the colon.

Rule: Use a colon to introduce a list when no introductory words like namely, for instance, i.e., e.g. precede the list.
Example: I need four paint colors: blue, gray, green, and red.

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Posted on Sunday, October 1, 2006, at 10:15 pm