It was the best of sentences, it was the worst of sentences - June Casagrande 2010
Punctuation basics for writers
When it comes to punctuation, professional writers should aspire to a higher standard than laypeople. A misplaced apostrophe or extra comma is much more forgivable in a casual e-mail than in a manuscript. Though no one punctuates perfectly, anyone who wants to write for publication should study the basic principles of punctuation.
Period
Use a period
• to end a sentence: Carrots are orange.
• to form abbreviations: The office is at 222 Oak Blvd., near the post office.
• to form some initialisms: The White House is in Washington, D.C.
Style rules vary on when to use periods with initials. Common initialisms like CIA, FBI, and LA may not have periods, depending on style.
The period is often unnecessary when an internal question mark or exclamation point appears at the end of the larger sentence that contains other terminal punctuation: Jim wanted to ask, "Are you kidding?"
Similarly, a sentence that ends with a period from an abbreviation or initial does not take an additional period at the end: He visited Orlando, Fla.
Comma
Use a comma to separate nouns, phrases, or clauses in a series. Brett likes peas, spinach, and cauliflower. Marianne studies hard, sleeps a lot, and never watches TV.
The comma before the conjunction and in these examples is called a serial comma or an Oxford comma. AP style says not to use the serial comma: Brett likes peas, spinach and cauliflower. Chicago style and many academics say that you should use it.
Use a comma to separate coordinate adjectives. Think of these as adjectives that modify the same noun independently: He was a mean, ugly, immoral clown. Note that this is different from noncoordinate adjectives: He wore a bright red Hawaiian shirt.
Usually, anywhere that and makes sense between the adjectives, you can use a comma in place of and: He was a mean and ugly and immoral clown. Noncoordinate adjectives often have a cumulative effect, and therefore and cannot logically replace them: a bright and red and Hawaiian shirt doesn't make sense as an alternative to a bright red Hawaiian shirt. Coordinate adjectives can often switch places without changing meaning: He was an ugly, immoral, mean clown. Noncoordinate adjectives cannot: He wore a Hawaiian red bright shirt.
The same comma rule works for adverbs. Coordinate adverbs should be separated with commas: They easily, happily, and regularly show up to work on time. But noncoordinate adverbs should not: They are a very happily married couple. Again, if an and would make sense, you can use a comma.
Use a comma to separate independent clauses joined with a conjunction.
This use is optional, but common:
We ate the stuffing, but the turkey remained untouched.
Mark drove the bus, and Stella sat in the back grumbling.
Renee had a good education, so she tried to hide that fact from Skeeter.
The comma is more likely to be omitted in short, clear sentences in which the independent clauses are joined by and: I like bananas and I like oranges.
Use a comma after introductory phrases and clauses. This use of the
comma is subject to individual judgment and tastes. In general, the longer the introductory matter, the more likely a comma will help the Reader understand how the information is organized: On Mondays Barry shows up early. But On the first Monday of every week in which he's scheduled, Barry shows up early.
Use a comma with a direct address. A direct address is a name or other moniker that you call someone directly: Hey, Jim. Listen, buddy. After you, sir. Bye, Pete. Note that there is no comma in Dear Jacob because dear is an adjective modifying Jacob and therefore works as part of the name. But Hello, Jacob takes a comma.
Use a comma to introduce or set off a direct quotation. Chuck said, "It's a great day." The docent said, "Don't touch the paintings," but Stan didn't listen. Longer quotations are sometimes introduced with colons instead.
Use a comma to set off parenthetical information. This includes nonrestrictive clauses, appositives, interjections, and many other modifying clauses and phrases.
A nonrestrictive clause is any clause that provides supplemental information and does not restrict the meaning of a modified word. Commas or the absence of commas around clauses can significantly change meaning by signaling whether the clauses are restrictive:
Men who like baseball are pleased, [only those who like baseball are pleased]
Men, who like baseball, are pleased, [all men like baseball and all men are pleased]
Fred's sister Jennifer is the youngest of the three Adams children. [Jennifer is essential information because it restricts the subject Fred's sister; without the name, you can't be sure which sister is being talked about]
Fred's sister, Jennifer, is his only sibling. [Here, Jennifer is nonrestrictive information; because we know that Fred has only one sister, her name in no way narrows down— restricts—the range of possible subjects]
An appositive is a noun phrase that refers to the same thing as another noun phrase immediately preceding it:
The president, a decisive man, will give a press conference.
My wife, Lorraine, will attend.
The temp, a real go-getter, impressed the boss.
The difference between appositives and titles is sometimes blurry:
The U.S. Senator, Steve Stevens, signed the legislation.
but
U.S. Senator Steve Stevens signed the legislation.
In the preceding example, we see that the could not logically modify U.S. Senator Steve Stevens because it would be akin to saying the Steve Stevens. So we know that the U.S. Senator is a noun phrase and that Steve Stevens is a separate noun phrase that must therefore be functioning as an appositive. Without the, U.S. Senator Steve Stevens could be a single unit with U.S. Senator functioning as a modifier.
The difference between appositives and noun-modifier combinations at times is purely a matter of intent:
Her book, The Rogue, is a best seller.
Her book The Rogue is a best seller.
In the first example, Her book is treated as the head noun phrase. The title is supplemental information—in this case, an appositive.
But in the second example, Her book is modifying the main noun phrase, The Rogue.
Use a comma to set off interjections. Bombo could tell you, of course, but then he'd have to kill you. (Of course is an interjection here.) Yes, you're right. (Yes here is an interjection.) The friar, indeed, was the murderer. (Indeed here is an interjection.)
The commas around interjections are often dropped when they would come too close to another comma—especially one used before a conjunction that is separating independent clauses: Bombo could tell you, but of course then he'd have to kill you.
Use a comma to set off other modifying phrases and clauses. In general, if an adverbial element such as a participial phrase or prepositional phrase contains parenthetical information, use commas:
Al, being the great guy that he is, brought pizza.
I, too, enjoy roller coasters.
Roger, with a wink and a smile, invited Josie to his room.
Ajax, undeterred by his enemies' skill, charged into battle.
Sometimes, the use of commas around adverbials is subject to your own judgment. For example, many say that words like too, either, and also should be set off by commas: Rodney ordered lobster, too. But this comma use is becoming less common: Rodney ordered lobster too.
Different styles disagree on whether Inc., Jr., and similar parenthetical elements in names and titles require commas. But if you use one before Inc. and so on, you must also use one afterward:
Warren bought shares of ABC, Inc., and Microsoft.
or
Warren bought shares of ABC Inc. and Microsoft, but not
Warren bought shares of ABC, Inc. and Microsoft.
Dates that include the month, day, and year use commas around the year:
Dale was hired on April 1, 1982, and stayed till last year.
not
Dale was hired on April 1, 1982 and stayed till last year. Apostrophe
Use an apostrophe
• to form possessives: The man's house. The doctrine's flaw. The Joneses' vacation.
• to denote omitted letters or numbers, especially in contractions: Can't is a contracted form of cannot. Doesn't is a contracted form of does not. It's is a contracted form of it is or it has.
• to avoid confusion, only when necessary: The sign read, "CDs for sale." But, The sign read, "CD'S FOR SALE." Here, the apostrophe is justified to make clear that S is not just another initial like C and D. In school, Anna got Cs, Bs, and a few A's.
Here, the apostrophe is justified after A because, otherwise, it would spell As. Some publications will bend these rules to make the writing easier on the eye: Anna got C's, B's, and a few A's. Publications disagree on which situations are confusing enough to justify apostrophes. For example, the Los Angeles Times writes the 1980s, but the New York Times's style is the 1980's.
The curve of an apostrophe, if any, should open to the left, not the tight. So, except in the simplest fonts, an apostrophe is identical to a closing single quotation mark, and should not be confused with an opening single quotation mark,
Quotation Marks
Use quotation marks
• for direct quotations: The president said, "This nation will prosper."
• in some styles, to denote words being discussed as words: The word "jeepers" isn't as common as it used to be.
• to denote irony or skepticism: Yeah, that cake looks "great," Mom. I "love" the green frosting.
• in some styles, around the titles of books, songs, movies, articles, and other compositions (other styles use italics for some of these works; consult a style guide for applicable rules and exceptions): Smithers, a character in "The Simpsons," likes the song "It's Raining Men."
When the matter in quotation marks could stand as a complete sentence, it begins with a capital letter: He said, "You should leave." When it's part of a sentence made complete by unquoted matter, the quoted portion begins with a lowercase letter. He said he wanted me to "get lost."
SINGLE QUOTATION MARKS
Use single quotation marks for quotations within quotations: "They told me, 'Never come here again,"' Roy said.
QUOTATION MARKS WITH OTHER PUNCTUATION In standard American style, a period or comma always goes inside a closing quotation mark:
Michelle said, "It's time."
When Dane said, "Hello," I didn't think he was talking to me.
In standard American style, a colon or semicolon always goes outside a closing quotation mark:
He told us the items on his "grocery list": beer and pretzels.
He sang "Oh, Canada"; "America, the Beautiful"; and other songs, many of them anthems.
In standard American style, question marks and exclamation points may go inside or outside closing quotation marks, depending on whether they apply to the whole sentence or to the quoted matter only:
Kojak's catch phrase was "Who loves ya, baby?"
but
Can you believe he called me "baby"? Also
He said, "This is an outrage!"
but
I'm outraged that he said, "baby"! The same rules apply to single quotation marks: Jeff always says, "Why ask 'why?'"
and
Joe said, "Have you noticed how much Jeff likes the word 'why'?"
Hyphens
A hyphen is generally less than half as long as an em dash. Use a hyphen
• to form a compound modifier before a noun: A sweet-talking woman. Adverbs ending with -ly are an exception: A happily married couple. This use of the hyphen is highly subjective. No two people—not even professional editors working for the same publication—hyphenate exactly alike. The main goal of the hyphen is to prevent confusion, even momentary
confusion: I saw a man-eating lobster versus I saw a man eating lobster.
• in words whose official spellings contain hyphens. The only way to be sure whether a word—especially a noun or verb— contains a hyphen in its official spelling is to check the dictionary. For example, Webster's New World College Dictionary says that the verb water-ski has a hyphen but the noun water ski does not.
• to attach certain prefixes and suffixes to words. There is no universal rule for knowing whether it's co-worker or coworker. Indeed, different styles advocate both. To know when to hyphenate prefixes and suffixes, consult the style guide or recommended dictionary that governs the publication you're writing for. In general, stylebooks tend to eschew hyphenating prefixes and suffixes: nondairy, midsentence, companywide. But they make plenty of exceptions.
Dashes
The em dash is generally more than twice as long as the hyphen. Em dashes are versatile and their uses overlap other punctuation.
Use an em dash
• to denote an abrupt change in tone or form: Vonnegut, Joyce, Hemingway—they were all heroes in Claire's mind.
• to set off parenthetical information: Mr. Beasley stormed through the house—he was very angry—demanding his slippers.
• to indicate a sudden interruption: Will he—does he dare defy me?
• to add emphasis: Raul was finished by noon—he's that good.
The en dash is less common and it's nonexistent in most newspaper styles. It's longer than a hyphen and shorter than an em dash. It can denote a range or a time span, usually meaning "up to and including" or just "to." During Brett's time at the firm, 1998—2002, he added five branches. The en dash can also do some of the hyphen's jobs when a hyphen wouldn't be as visually clear. For example, it can connect hyphenated items to each other: It was a semi-public—semi-private organization, or it can connect a multi-word term like "World War I" to another word or prefix, as in: World War I—era planes.
Colon
Use a colon
• to introduce a list: Here are the items that will be served: stuffed mushrooms, beef skewers, and cheese puffs.
• to add emphasis: Let me tell you this: you're awesome. AP style says that if the material after the colon forms a complete sentence, it should begin with a capital letter: You're awesome. Chicago style says that only if the matter introduced by the colon consists of two or more sentences should it begin with a capital letter.
• to introduce a quotation that contains two or more sentences. This use is optional. A comma is often used instead.
• to follow a direct address in correspondence: Dear Ms. Williams: This use is optional. A comma is often used instead.
Parentheses
Use parentheses to set off information that is less important than or somehow removed from the main passage: I was driving an Escalade (an expensive one) when I hit the center divider. A period goes before the closing parenthesis only if both the main text and the parenthetical are complete stand-alone sentences: I was driving an Escalade. (It was an expensive one.) That was the day I hit the center divider. Otherwise, the parenthetical takes no period.
Question Mark
Use a question mark with an interrogative sentence (a question): Who moved my guacamole? A question mark is usually considered terminal punctuation because it can end a sentence. But occasionally a question mark can appear midsentence: When he asked, "How are you?" it was as though he actually cared.
Exclamation Point
Use an exclamation point to denote high emotion or something exclaimed: You monster!