This document provides an overview of common punctuation errors and guidelines for proper punctuation usage. It discusses apostrophes, colons, semicolons, commas, the Oxford comma, dashes, ellipses, exclamation points, parentheses, question marks, and quotation marks. For each punctuation mark, it provides examples of correct and incorrect usage and explains the functions and rules. The document aims to help writers avoid unintended meanings from misused punctuation.

1. SPOTTING AND AVOIDING
DANGEROUS
PUNCTUATION ERRORS
Let’s Eat Grandpa!

2. Why know this stuff?
— Punctuation performs many MANY functions, and
knowing these gives your writing cohesion and
expressive power.
— Misused punctuation can create unintended
meanings and misunderstandings.

3. Why know this stuff?
— Punctuation performs many MANY functions, and
knowing these gives your writing cohesion and
expressive power.
— Misused punctuation can create unintended
meanings and misunderstandings.
— Mostly, it’s so you don’t look silly.

4. The Apostrophe [ ’ ]
The main functions of apostrophes are:
1. To indicate omitted letters.
(can’t, let’s, won’t, havin’, Jo’burg [Johannesburg])
2. To show the possessive.
(Larry’s book, the Bank’s money, the Jones’s car, in
five days’ time)

5. [’] Apostrophe: Common Usage Errors
— Multiple possessives.
¡ Incorrect: “This is a sequel to Jeremy Paul’s and Alan
Gibson’s play” (London Times)
¡ Correct: “This is a sequel to Jeremy Paul and Alan Gibson’s
play”
÷ Rule: When possession is held in common, only the last person or
entity gets the possessive.

6. [’] Apostrophe: Common Usage Errors
— Multiple units of measure.
¡ Few people make a mistake with singular units of measure:
÷ Correct: “All in a day’s work”
¡ But it’s common to leave out apostrophes from plural units:
÷ Incorrect: “I got three classes worth of credit”
÷ Incorrect: “He lost three weeks worth of wages”
÷ Correct: “I got three classes’ worth of credit.”
÷ Correct: “He lost three weeks’ worth of wages.”
¡ Often, a more elegant solution is to cut out the extra words:
÷ “I got credit for three classes”

7. The Colon [:]
— Colons indicate the start of a series. A colon should
not separate a verb from its objects in enumerations.
¡ Incorrect: “The four states bordering Texas are: New Mexico,
Arkansas, Oklahoma, and Louisiana.
¡ Correct: “Texas is bordered by four states: New Mexico,
Arkansas, Oklahoma, and Louisiana.

8. The Semicolon [;]
— The semicolon is heavier than a comma but lighter
than a period. It’s main function is to divide two
ideas that are connected in sense but not by a
conjunction.
¡ Example: “You take the high road; I’ll take the low road.”
÷ (You can often replace a semicolon with the conjunction “and.”)

9. The Semicolon [;]
— Semicolons are also used in lists where the individual
items contain commas. This avoids confusion
between list items.
÷ Example: “There are basically two ways to write: with a pen or
pencil, which is inexpensive and easily accessible; or by computer
and printer, which is more expensive but quick and neat.”
¡ … and to separate long clauses, or clauses with commas.
÷ Example: “Some people write with a word processor, typewriter,
or a computer; but others, for different reasons, choose to write
with a pen or pencil.”

10. The Comma [,]
“The most abused of punctuation marks”
-Bill Bryson
— Comma use is necessary in three situations and
recommended in a fourth:
1. When the information is clearly parenthetical.
2. When the information is non-restrictive.
3. With forms of address (like with poor Grandpa)
4. With interpolated words in a sentence.

11. The Comma [,]
1) Parenthetical Information
— “Seymour Hersch, an investigative journalist for The
New Yorker, was criticized for his reporting on prison
abuse.”
÷ Notice how the sentence would still be grammatical if you took out the
parenthetical clause.
— “Toyota, according to surveys, is rated highest among
automakers in reliability and customer satisfaction.

12. The Comma [,]
1) Parenthetical Information
— Incorrect: “At his home on Lake Washington/east of Seattle,
Bill Gates likes to entertain wealthy donors to his foundation.”
(I put a slash where the missing comma should be.)
— Incorrect: “At nine she won a scholarship to Millfield, a
private school, for bright children.
¡ If you remove what’s presented as parenthetical, the sentence
would (incorrectly) read:
“… she won a scholarship to Millfield for bright children.”

13. The Comma [,]
1) Parenthetical Information
— Incorrect: It’s become clear that people don’t want to
buy Hummers, the most efficient gets 10 MPG, with gas
prices as high as they are.
¡ Here, the parenthetical information is a stand-alone sentence, and
therefore needs to be set off with stronger punctuation, like dashes or
parentheses.

14. The Comma [,]
— Sometimes, parenthetical information can so long it
makes it difficult to follow the sense of the sentence.
“When Nasser’s successor, Anwar Sadat, expelled the Russians, [the
Russians] cultivated a trio of dictators, Muammar el-Qaddafi in Libya,
Saddam Hussein in Iraq and Hafez al-Assad in Syria. All three, running
merciless, dynastic-Mafia regimes behind the facade of
socialistic parties, central planning and Stalinesque cults of
personality, took quickly to their new benefactors.” ( NY Times)

15. The Comma [,]
2) Nonrestrictive Information
— Incorrect: “The chairman of BBC George Howard
claimed that cable TV would be socially divisive.”
¡ The writer has failed to understand the difference between
1. “BBC chairman George Howard claimed…” and
2. “The chairman of BBC, George Howard, claimed…”
Ø In (1), George Howard is essential to the sense of the sentence.
Ø In (2), the name is nonrestrictive.
(If you take the name out of each sentence, only (2) reads grammatically.)

16. The Comma [,]
3) With Forms of Address
— Always put commas around name or titles when
addressing people.
¡ Incorrect: “Hit him Jim, hit him!”
A British tabloid once captioned a story illustration:
÷ “I’m choking Mr. Herriot” when what was meant was
“I’m choking, Mr. Herriot.” Two very different meanings.
(A well known book on punctuation is called Eats Shoots and Leaves.)

17. The Comma [,]
4) Interpolated words or phrases
(recommended)
— What the heck is an interpolated word or phrase?
¡ These are words like “However,” “Moreover,” “Finally,”
and “…, say,…”
¡ and phrases like, “In a nutshell,” “At the end of the day,”
— Sometimes, leaving out a comma can create ambiguity
(especially with “however”). Note the contrast between these
sentences:
¡ However hard he tried, he failed.
¡ However, he tried hard, but failed.
÷ A comma in the first would be incorrect; in the second, the comma is needed.

18. The Oxford Comma [,]
— The Oxford comma (AKA “serial comma”) occurs
before the and at the end of a list. American
journalism typically doesn’t employ this comma, but
most style guides recommend it, including MLA &
APA.
¡ Example: “They went to Spain, France, and Italy during their
recent European trip.

19. The Dash [—]
— Dashes are used in pairs to enclose parenthetical
information:
¡ Correct: “The company – it is the largest of its kind in the European
sector – has reported higher earnings for the quarter.”
÷ A common mistake is to leave off the closing (2nd) dash.
— Dashes also mark a break in a sentence:
¡ Correct: “There are only two things we can count on – death and
taxes.
Note: dashes are best used sparingly, and you should
never include more than one pair in a sentence.
(there are exceptions in literature, which allows more freedom than academic
writing)

20. The Ellipsis […]
(plural: ellipses)
— This punctuation mark (yes, it’s a single mark),
consists of three evenly spaced periods and indicates
material that has been omitted (removed).
— In quoted material, it often occurs in square brackets
[…] to show that the author who is quoting has
removed words fr0m the quote.
Note: An ellipsis used at the end of a sentence is followed by a fourth
period.

21. Exclamation Point [!]
— These are used to show strong emotion:
¡ “Help me!” / “Get out!”
— They should not be used to give emphasis to simple
statements of fact:
¡ “It was bound to happen sometime!”
÷ A better solution here might be to italicize “sometime.” However,
italicizing for emphasis should be used very sparingly.

22. Parentheses [( )]
— Parentheses, like dashes, are used for information
that is so incidental to the main thought that it needs
to be separated from the sentence that contains it.
— In other words, use parentheses when a comma isn’t
strong enough.

23. Parentheses [( )]
— Parenthetical information should have no grammatical
effect on the sentence.
¡ Incorrect: “Ms. Smith (and her father before her) have made a
success of the family business.”
¡ Correct: “Ms. Smith (and her father before her) has made a success
of the family business.”
— But the sentence’s grammar influences the parenthetical.
¡ Incorrect: “No Japanese citizens were allowed to become citizens
(and thus could not vote) until 1952.”
¡ Correct: “No Japanese citizens were allowed to become citizens
(and thus vote) until 1952.”
÷ otherwise, the sense is that “… no Japanese citizen could not vote.”

24. Parentheses [( )]
— If parentheses are used at the end of a sentence, the
final period (or question or exclamation mark) goes
outside of the closing parenthesis (like this).
— (But when an entire sentence is parenthetical, then
the period stays inside of the closing parenthesis.)

25. The Question Mark [?]
— Direct questions always take a question mark:
¡ “Who is going with you?”
— Indirect questions never do:
¡ “I was wondering who is going with you.”

26. Quotation Marks [“”]
Quotations and Punctuation
Quotation marks enclose quoted material – this is not
controversial. Where conventions differ is where to put the
punctuation.
— American convention dictates that the punctuation goes inside
of the quotation. (However, you will see a few writers differ.)
¡ He said, “I will not go.”
— An exception is when the original quote is not a question, but he
sentence where it is quoted is:
¡ Did I hear him correctly when he said, “Take me to Algeria”?

27. Quotation Marks [“”]
Quotations and capitalization.
— If the quotations are setting off a complete statement, the
first word on the quotation should be capitalized:
¡ He said, “Victory is ours!”
— This is not the case when the quotation is preceded by that:
¡ He said that “victory is ours.”

28. The Period [.]
… last but far from the least.
Two main errors arise with period use, and both of
them arise from its absence:
1. Run-on sentences
2. Trying to say too much in a single sentence.

29. The Period [.]
Run-on sentences.
(this is where I really hope you’re attention)
— Look at the following sentences (from major publications). A
slash is inserted where the period should be.
¡ “Although GEC handled the initial contract, much of the equipment is
American, / the computers and laser printers come from Hewlett
Packard.”
¡ Confidence is growing that OPEC will resolve its crisis, / however the
Treasury is drawing up contingency plans.”
¡ “Funds received in this way go towards the cost of electricity and water
supply, / industries, shops and communes pay the higher rate.”
Note: There are several fixes for these run-ons, but the period is the most
efficient.

30. The Period [.]
2. Trying to say too much in a single sentence.
¡ Example: “The measure would include plans to boost investments for
self-financing in industry, coupled with schemes to promote
investment and savings, alleviate youth unemployment, fight
inflation, and lower budget deficits, as well as a new look at the
controversial issue of reducing work hours.”
— Notice how the last clause is grammatically unconnected
to what came before (i.e. it isn’t parallel).
— The sentence cries out for a period so that the reader can
absorb the information.

31. Source material for slideshow
Many of the examples and much of the wording in this
slideshow were shamelessly adapted for the benefit of
students from a copy of Bill Bryson’s helpful reference,
Bryson’s Dictionary for Writers and Editors:
Bryson, Bill. Bryson’s Dictionary for Writers and
Editors. 1991. New York: Broadway Books: 2008.
Print.