Author: CNS - LCT
Last saved by: Teresa Bulman
Company: Portland State University

Punctuation Guide
(T. L. Bulman and S. Hill 2005)

The comma
The following are rules to remember:
a)	Use a comma before a coordinating conjunction (and, or, but, nor, yet, for, so) that separates two independent clauses.
b)	Use a comma after an introductory word, phrase, or clause that comes before a main clause.
c)	Use commas around words, phrases, and clauses in the middle of a sentence when they are not essential to the meaning of the sentence.
d)	Use commas between items in a series.
e)	Use commas before and after a quotation within a sentence.
f)	Use a comma before an afterthought or contrasting element.
g)	Use commas to set off geographical names, items in date, and professional titles.

The dash (or, the “em dash”)
Dashes (—) basically separate major parts of a statement and are used in the following instances:
a)	To set off parenthetical material—like this—that deserves emphasis.
b)	To set off appositives that contain commas. An appositive is a noun or noun phrase that renames a nearby noun. (Dr. Bulman—a professor at PSU—teaches the geography of Africa.)
c)	To prepare for a list, a restatement, an amplification, or a dramatic shift in tone or thought.

Parentheses
When to use parentheses:
a)	To enclose supplemental material, minor digressions, and afterthoughts that are extra information.
b)	To enclose letters or numbers labeling items in a series: Go to Chapter Six (pages 100-150).
c)	To enclose the abbreviation or acronym that follows its full name: Portland State University (PSU).

The ellipsis mark (. . .)
When to use ellipsis:
a)	To indicate that you have deleted material from an otherwise word-for-word quotation.
b)	If you delete a full sentence or more in the middle of a quoted passage, use a period before the three ellipsis dots.
c)	It may also be used to mark a hesitation or an interruption in speech or to suggest unfinished thoughts.

A good resource for rules and examples is http://www.grammarbook.com/punctuation/cnt_punc.asp