A female student of mine once complained that "Punctuation is stupid. What good are commas and stuff? Who needs them?" I responded by showing her two of my favorite examples of the importance of punctuation, and here they are:
I asked her if she agreed with that sentence, and, of course, she violently disagreed. Then I punctuated the sentence in the following way:
All of a sudden, she thought the sentence made perfect sense. A second example deals with the difference between an appositive and direct address.
Introduction
Woman without her man means nothing at all.
Woman: without her, man means nothing at all.
Call me fool if you like.
Call me, fool, if you like.
1a. Use an apostrophe to signal possession.
The girl’s dress is pretty. (one girl, one dress)
The girl’s dresses are pretty. (one girl, many dresses)
The girls’ dresses are pretty. (many girls, many dresses)
The girls’ dress is pretty. (many girls, one dress [a poor family])
Note: Often, using the possessive form may create an awkward adjective-noun pair. If so, rewrite the sentence, using a noun and a prepositional phrase beginning with of.
The Nuclear Test–Experimental Science Program’s accomplishments were revolutionary. (awkward use of the possessive)
The accomplishments of the Nuclear Test–Experimental Science Program were revolutionary. (better)
James’s expertise is in microbiology.
Note: Although the word "James" ends with an s, the possessive form demands an ’s because it is sounded in speech.
1b. Use an apostrophe to signal the omission of a letter (or letters) as in a contraction.
It’s a warm day.
They’ve had a bad time.
Note: It’s is a contraction, meaning "it is" or "it has." Its is a possessive pronoun, meaning "belongs to it." In general, avoid using contractions in technical reports.
Its color has faded.
2a. Use brackets to function as parentheses within parentheses.
The two presidents (one from the University of California at Los Angeles [UCLA} and the other from Stanford) are collaborating on the project.
2b. Use brackets to enclose editorial comments.
3a. Use bullets to introduce items that are not sequential.
• A solid background in the subject matter.
• A desire to stay current by exhaustive reading in the subject matter.
• A love of learning.
• A love of students.
• An ability to command respect.
• A large dose of patience.
We divided our assignment into four tasks: (1) gathering the data, (2) organizing the material gathered, (3) preparing a rough draft, and (4) writing the final copy.
4a. Use a colon to introduce a list.
The leader’s talk dealt with many topics: consistency, uniformity, professionalism, loyalty, and attendance at social functions.
4b. Use a colon to separate two independent clauses when the second clause is an explanation of the first.
My good friend, Dan, has a definite opinion about all incumbent politicians: throw the bums out!
His facial expression signified one thing: total interest in what she was saying.
5a. Use a comma to separate two independent clauses that are joined by a conjunction. (An independent clause is a group of words including a verb that could stand alone as a sentence.)
I went to the store, and I bought bread.
Note: "I went to the store" is an independent clause and could therefore stand alone as a sentence. The same is true of "I bought bread."
I went to the store and bought bread.
Note: "I went to the store" is an independent clause, but "bought bread" is not and therefore cannot stand alone as a sentence. It is thus incorrect to put a comma before "and."
5b. Use a comma to separate elements in a series.
Note: The final comma in the series, referred to as the serial comma, is optional, but I prefer to use it to avoid ambiguity.
5c. Use a comma to separate an introductory clause or phrase from the main part of the sentence.
Although we are improving our understanding of male-female relationships, many questions remain unanswered.
Because you are such an intelligent person, you surely can understand all of these examples.
Note: If the clause or phrase follows the main part of the sentence, do not use a comma.
You surely can understand all of these examples because you are such an intelligent person.
5d. Use a comma on both sides of an appositive to separate it from the rest of the sentence. (An appositive is inserted material that further explains or means the same as the preceding term.)
President Bush and General Secretary Gorbachev, the leaders of the two great superpowers, signed the Strategic Arms Reduction Treaty on July 31, 1991.
My wife, Claudia, is a bright and sensitive woman.
Note: Such abbreviations as Jr., Inc., and Ltd. are similar to appositives and are set off by commas.
5e. Use a comma to separate a person(s) or thing(s) directly addressed from the rest of the sentence.
I am very fortunate, Claudia, to have met you.
Rover, fetch my slippers!
5f. Use a comma to separate two or more consecutive adjectives.
Note: If the first adjective describes the second adjective and not the noun or if it describes the combination of the second adjective and the noun, do not use a comma between the two adjectives.
We are pursuing collaborative research programs with the former Soviet Union.
She has fiery red hair.
5g. Use a comma to separate inserted, additional, unessential, or nonrestrictive material from the rest of the sentence.
It is obvious to me, although not apparent to everyone else, that the world is a beautiful place.
John, who lives next door to me, works in Oakland.
All students who are caught cheating on tests will flunk. (The who clause is essential to the meaning of the sentence.)
All water wells that have an unsafe level of contaminants must be immediately shut down. (essential, restrictive)
Note: Use the relative pronoun that to introduce a restrictive clause, but use the relative pronoun which to introduce a nonrestrictive clause.
The theory of relativity, which was one of Einstein’s greatest contributions to science, was a revolutionary theory. (unessential, nonrestrictive)
The theory that all men are created equal is tested in the U.S. in many ways. (essential, restrictive)
Note: As a rule, if the material can be deleted from the sentence without destroying the sentence’s meaning, the material is nonrestrictive and is set off by commas. However, if the material is deleted and the meaning of the sentence is destroyed or significantly altered, the material is restrictive (essential) and is not set off by commas.
Eugene O’Neill, who wrote Long Day’s Journey into Night, is the only American playwright who has won the Nobel Prize. (unessential, nonrestrictive)
The author who wrote Rejected by Misfortune may win the Nobel Prize.
My sister Lynn is a bright, sensitive woman. (The word "Lynn" is restrictive, essential. I may have other sisters who are stupid and brutish!)
5h. Use a comma to avoid confusion.
He walked in, in the middle of the discussion about situational ethics.
At home, work is emphasized.
For Stanley, Graham was an inspiration.
6a. Use ellipses to signal an omission within the sentence.
When I arrived home three hours late, my wife angrily shouted, " . . . ." Politeness prohibits me from quoting her exactly.
Note: Use four dots if the omission is the last part of the quoted material, the entire sentence or more, or the entire paragraph or more. If the omitted material is in the middle of a sentence, use three dots.
7a. Use an em dash to separate enclosed material.
Because we were unable to verify some of the information—we will discuss this in the next chapter—we decided not to print the article.
It was quite an experience—an unbelievable experience—for all who witnessed it.
Note: The em dash separates enclosed material as do the comma and the parenthesis, but the em dash signals an abrupt break. Also note that the em and en dashes separate, whereas the hyphen combines.
8a. Use an en dash to signal a range.
He conducted the research on July 17–24.
Note: Use "between July 17 and July 24" and "from July 17 to July 24" instead of "between July 17–24" and "from July 17–24."
8b. Use an en dash instead of a hyphen in a compound adjective if one of the adjectives is a hyphenated word or consists of two words.
They conducted an x-ray–opacity experiment.
She is a UC Berkeley–LLNL employee.
He caught the Chicago–Des Moines flight.
8c. Use an en dash for a minus sign.
9a. Use an exclamation point to signal a strong emotional response (e.g., surprise, fear, anger, joy, and amazement)
Oh, the joy of being an English instructor!
10a. Use a hyphen to signal that two (or more) words have been combined to form another word. (Such words are often called unit modifiers and therefore act as adjectives.)
The president-elect will reside in the White House beginning next month.
He needed a 7-1/2-inch pipe. (If you have a computer, with the use of superscript and size reduction on the 1 and reducing the size of the 2, you can create this instead: 71/2.)
Note: Sometimes two words are combined (and spelled with a hyphen) to form a verb or a noun.
We will mass-produce the item to lower its price. (verb)
Self-discipline is essential if one is to succeed in life. (noun)
10b. Use a hyphen to break a word that is too long to fit on a line.
rapist who also treated her father. (Notice that the word "therapist" creates confusion about whom Ellen is visiting when it is hyphen-
ated in the above fashion, but the word "hyphenated" in this sentence creates no such problem.)
Note: Because of automatic word-wrapping on computers, the line-break hyphen is seldom used. Break the word only between syllables, and if unsure about syllabication, use the dictionary.
11a. Use parentheses to separate enclosed material.
My friend Jim (all of his other friends would agree) is quite a character.
Note: A parenthetical phrase, clause, or sentence is unessential material that is an interruption in the text. Set off such a phrase or clause with commas, parentheses, or em dashes. Do not set off a parenthetical sentence with commas but only with parentheses or em dashes.
The natural gases from which helium is made are carried, in a pipeline eleven miles long, from the Amarillo field.
The natural gases from which helium is made are carried (in a pipeline eleven miles long) from the Amarillo field.
At times—they were more than a few—the situation seemed hopeless.
Note: Parentheses, like the comma and em dash, set off material from the rest of the sentence, but the parentheses and em dash remove the material farther away than does the comma.
11b. Use parentheses to separate an acronym from its appositive.
The Department of Defense (DOD) and the Department of Energy (DOE) are powerful arms of the government.
Note: After the first use of the appositive-acronym combination in a document, use only the acronym and without parentheses.
12a. Use a period to signal the end of a declarative sentence (a statement of fact) or an imperative sentence (a command).
Get out of here.
12b. Use a period with some abbreviations (but not with abbreviations of units of measurement in technical writing).
Mr. Willis’ address on commas was very informative.
During a typical 2–min pass, we acquired 1200 images.
12c. Use a period at the end of a bulleted item.
• Putting the lug nuts back on and tightening them.
• Taking the lug nuts off the flat tire.
• Putting on the new tire.
• Removing the flat.
Note: If the above items were listed sequentially, numbers would be used in place of bullets.
13a. Use a question mark to signal a direct question or an editorial doubt.
My favorite author is Eugene O’Neill (1888?–1953)
I am wondering why you are reading this sentence. (indirect question)
14a. Use quotation marks to signal quoted words, phrases, and sentences.
When asked what were the two most important qualities of a teacher, she responded, "kindness and consistency."
The manager kept referring to "our mission for the future."
My mother often told me, "When I am gone and someone on the phone asks, ‘Is your mother at home?’ or some similar question, you answer by saying, ‘Yes, but she is busy right now.’ "
14b. Use quotation marks (or italics) for the first use of an unusual, technical word that is presumably unfamiliar to the reader.
14c. Use quotation marks (or italics) with a word or phrase highlighted for the purpose of definition or explanation.
I used the word static in the sense of "unchanging."
15a. Use a semicolon to separate two closely related independent clauses.
Note: The semicolon in the above sentence is a replacement for a comma followed by a coordinating conjunction.
I went to the store; I bought bread.
Note: This is incorrect because the two independent clauses are not closely related. Use a period [or a comma plus "and"] instead.
15b. Use a semicolon to separate items in a list when the items already contain commas.
My children were born on March 16, 1970; November 2, 1971; October 24, 1977; October 26, 1979; and October 23, 1984.
My favorite cities are London, England; Paris, France; Rome, Italy; Valencia, Spain; and Milpitas, California.
Brad is a dear friend, a longtime friend; and even though he is very, very busy, he always manages to find time for me and for my concerns; but I am not yet ready to canonize him! (This "sentence" is grammatically correct but clumsy, and it would be preferable to break it up into two or more sentences.)
15c. Use a semicolon to separate two independent clauses when the second clause begins with a transition word. Put a comma after the transition word.
Note: Examples of transition words are: however, moreover, thus, nonetheless, nevertheless, etc. Do not confuse transition words with coordinating conjunctions such as: for, and, nor, but, or, yet, so (the FANBOYS).
I studied; nonetheless, I failed.
I studied for many more hours and then retook the test; thus, I finally passed.
16a. Place periods and commas inside quotation marks.
When the teacher lectured us on "acting in a mature fashion," some of us failed to listen maturely.
16b. Place colons and semicolons outside quotation marks.
In his homily, the preacher kept using the term, "efficacious grace"; however, none of us knew what the term meant.
I have two reasons for loving Robert Frost’s poem, "The Road not Taken": it challenges my mind, and it moves my soul.
16c. Place exclamation points and question marks inside quotation marks when they are part of the quoted material and outside when they are not.
In a soft voice, and with no sign of emotion, the murderer said, "I have done nothing wrong"! (The exclamatory emotion is that of the speaker and not of the murderer.)
The man shouted, "Get out of here now!"
Was President Bush thinking rationally when he said, "Dan Quayle is the best man for the job"? (Unfortunately, the speaker, not the man in power, asked the question.)
Mom asked, "Have you cleaned up your room yet?"
16d. Place periods, exclamation points, and question marks inside parentheses and brackets when they are part of the parenthetical or bracketed material; otherwise, place them outside.
Was Mr. Bush thinking clearly when he named his running mate? (It is unfortunate that I, and not the President, asked the question.)
Mr. Bush was not thinking clearly when he named his running mate (the one who spells potato with a final "e").
My son (I almost died!) told the crowd the story about my most embarrassing moment.
He actually told the crowd about my most embarrassing moment (the sliver in the "unmentionable" area)!
When I first met Claudia (could she possibly have been interested in me?), I fell in love immediately.
Do you believe that I proposed to Claudia less than 24 hours after I met her (January 2, 1968)?
16e. Place semicolons, colons, and commas outside parentheses and brackets.
My kids wanted to go to that particular movie (all of their friends had recommended it); however, I felt it was too violent.
Five great American novelists have won the Nobel Prize for Literature (Eugene O’Neill is the only American playwright to do so): John Steinbeck, Ernest Hemingway, William Faulkner, Pearl Buck, and Sinclair Lewis.
Because he publicly praised Dan Quayle to the skies (he did not want to appear as one who "waffles" on his opinions), Mr. Bush had to stick with the Indiana Senator as his running mate.
16f. Do not use any punctuation before an opening parenthesis, and use only terminal punctuation (periods, exclamation points, and question marks) before a closing parenthesis. Omit colons, semicolons, dashes, and other punctuation that is not terminal.
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