Purdue
University North Central Writing Center Handout
General
Punctuation Rules
Periods
1.
A period is used to end a sentence.
2.
(A period is used inside parentheses if the entire sentence is inside the
parentheses.)
3.
A period is placed outside the parentheses (if the material inside the
parentheses is only part of the entire sentence).
4.
A period is used “inside quotation marks at the end of a sentence.”
Exclamation
Point
1.
An exclamation point is used at the end of an emphatic statement!
2.
And exclamation point is treated the same as a period in the examples
cited in rules 2, 3, and 4 under “Periods.”
Questions Marks
1.
Is a question mark used a the end of an interrogative sentence? (You
bet!)
2.
A question mark is treated the same as a period in the examples cited in
rules 2, 3, and 4 under “Periods.”
Commas
1.
Commas are used between two independent clauses separated by a
conjunction, and the comma appears before the conjunction.
Conjunctions are such words as and, but, for, nor, or, so, and yet.
2.
When a sentence begins with an adverbial clause (as this one does), a
comma separates that clause from the rest of the sentence. Other adverbs commonly used to start sentences include after,
if, as, because, and although.
3.
A nonrestrictive clause, which is a clause that could be dropped from a
sentence without changing the meaning of the sentence, is often set off with
commas.
4.
A clause that begins with a form of a verb is set off with a comma from
the rest of the sentence. Having
explained this rule, I will now move on to the next rule.
5.
Parenthetical words, phrases, and clauses should be set off with commas.
(You can also use parentheses or dashes.)
Parenthetical expressions are those that can, it would seem, be removed
from the sentence without changing its meaning.
6.
Friends, when you open a sentence with a form of address or an
introductory word, you should set off that address with a comma.
7.
Appositives (words or phrases placed so that they directly modify nouns
in the sentence) should be set off by commas.
This handout, General Punctuation Rules, includes this and many other
helpful examples.
8.
Two adjectives that modify the same noun should be separated by a comma.
If you can insert the word and between
the adjectives without changing the meaning of the sentence, separate the
adjectives with a comma. Users
should take a long, hard look at these punctuation rules.
9.
Use commas to separate the elements in a series that contain three or
more words, phrases, or clauses.
10.
Separate two like words with a comma to prevent confusion: The dog never comes in, in the summer.
11.
Use commas in dates to separate the day and month from the year:
April 12, 1986 or May, 1986. Also,
use commas to separate elements of an address when written out:
3468 Shelly Lane, Aurora, Illinois.
12.
Use commas inside quotation marks when writing a direct quote:
“She’s allergic to work,” said
Cindy’s brother.
Semicolons
1.
Use semicolons between two independent clauses of a compound sentence
when they are not separated by a conjunction.
Do not use a semicolon to join just any two independent clauses; they
should be closely related.
2.
Use semicolons to separate the elements in a series that contains other
punctuation. To enter the Portals
contest, a student needs to prepare a cover page, indicating entry class; submit
the cover page and entry to the Letters and Language office, LSF 68; and meet
the deadline, February 13.
3.
When a semicolon follows quoted material, place the semicolon outside the
quotes: Her trip to Mexico left her
with a case of “Montezuma’s Revenge”;
she found it did not agree with her.
Colons
1.
Use a colon to separate two independent clauses of a compound sentence
when the second clause makes the first clause clearer:
several of the examples in the “Commas” section illustrate this rule.
2.
You may use a colon to introduce a series or list:
either words, phrases, or clauses.