Table of contents
Punctuation is used to make text easier to read and to convey clear and specific meaning. It is used to divide words into grammatical units, like clauses within sentences. Punctuation marks consist of a set of standardized symbols: periods, commas, semicolons, colons, question marks, exclamation points, apostrophes, quotation marks, hyphens and dashes, and parentheses and brackets. The proper use of these symbols is governed by grammatical and stylistic guidelines.
A period is used to end a declarative sentence or imperative sentence. The period stands inside quotation marks.
- They are going to the mall.
- Hand me the book next to you, please.
- Finish your dinner so you can go to sleep.
- She said, “I’m not leaving my purse on the table unattended.”
Periods are also often used with abbreviations and acronyms.
- Massachusetts Ave. begins in Dorchester.
- The U.S. and China are the countries most responsible for greenhouse gas emissions.
If a sentence ends with an abbreviation or acronym, no additional period is required.
- They will bring the dishes, serving pieces, flatware, etc.
- The train arrives at ten P.M.
- Their son recently received his B.S.
A comma is used to separate two independent clauses joined by any of the following coordinating conjunctions: and, but, for, or, and nor.
- The men remained in the kitchen, and the women went out to the garden.
- We were supposed to go boating, but the storm changed our plans.
- Should we stay home tonight, or should we go out to dinner?
A comma is used to separate a dependent clause from the main clause that follows.
- Even though the concert was great, we had to leave early.
- When I was through with the dishes, I sat down with a glass of wine.
If the dependent clause follows the main clause, the comma is often not used.
- I sat down with a glass of wine when I was through with the dishes.
A comma is used to separate an introductory element from the main clause of a sentence.
- Running as fast as he could, Chris finished second in the marathon.
- Taken completely by surprise, the enemy was forced to surrender.
A comma is used after a wide range of introductory words, including yes, no, oh, and well, at the beginning of a sentence.
- No, I can’t tell you why she left so suddenly.
- Well, they may stay in the guest room if they leave by tomorrow afternoon.
A comma is used to separate an apposite phrase from the rest of a sentence. An apposi-tion is a word or phrase placed after another to provide additional information about it or to explain it.
- Erin likes that dress, which she bought at a Macy’s sale, because it fits so well.
- We saw that blue car, the one that is parked right over there on the street, the last time we ate here.
- My game console, an Xbox, offers crystal clear graphics.
A comma is used to separate declarative elements from a clause that poses a question.
- She is depending on those grades, isn’t she?
- That movie was beautiful, don’t you think?
A comma is used to separate groups of numbers, the different elements of an address, and the date from the year. A comma ordinarily is not used to separate the name of a month from the year.
- Their twentieth wedding anniversary was on March 10, 2000.
- Barbara and I lived at 232 Lorraine Road, Austin, Texas for roughly ten years.
- He left South Korea in May 1977.
A comma is used to separate interrupting elements from the rest of a sentence.
- If Shawn writes more than 20 pages by the end of this weekend, and we doubt he will, he will treat himself to a smoothie.
- When John finishes his degree, which would be some kind of a miracle, he plans to start his own business.
- Karen won a prize in the lottery and, with any luck, will be able to pay off her debts.
A comma is used at the end of the greeting of a personal letter and at the end of the closing.
- Dear Mr. Mustar,
- Sincerely yours,
A comma is used to separate numbers composed of four or more digits (except for years).
- The company made more than $8,000,000 in the last fiscal year.
- We need 1,500 cubic yards of concrete for the parking lot.
A comma is sometimes used when the meaning of a sentence needs to be preserved and to avoid confusion.
- She asked me why I hadn’t kissed her, and giggled. (to make clear that it is she who giggled)
A comma is used to separate direct quotations from the rest of a sentence.
- Mr. Wilson told me, “There is no gain without some loss.”
- The president always said, “To protect our freedom, I must be conservative.”
A comma is used to separate the person or persons being addressed from the rest of the sentence.
- Ladies and gentlemen of the jury, may I have your attention?
- Jack, turn down the volume on the TV.
A comma is used to separate items in a series.
- We bought apples, plums, and a bushel of tomatoes.
- They hope to visit France, Germany, and the Netherlands.
A semicolon is used to mark a break between independent clauses in the same sentence. It links clauses that are closely related.
- She has asked them to leave several times; they had a habit of overstaying their welcome.
- For the second time, he rescued a drowning child; his bravery is well known.
A semicolon is also used before conjunctive adverbs and transitional phrases that join independent clauses.
- They had been walking around the neighborhood for hours, looking for the lost dog; at the same time, they talked to neighbors they had never met before.
- The salesman let the man take the car for a drive; soon after, he had the eager buyer signing the purchase papers.
A semicolon is used to join independent clauses connected by a coordinating conjunction (and, but, for, or, nor, so, or yet) when at least one of the clauses contains a comma.
- It was time for the football team to take a break, drink some water, and stretch; but there were so many different exercises, and they had such a limited space, that they would need to be on break for too long to really stretch properly.
A semicolon is used to separate a series of elements from the rest of the sentence when at least one of the elements is long and contains commas. These elements can be phrases or clauses.
- In his analytical thesis on the Ninth Symphony, the author decided to include information about Beethoven’s father, Johann, who was his first music teacher; Christian Gottlob Neefe, his most important teacher in Bonn; and Giulietta Guicciardi, his fiancée.
A semicolon is placed outside quotations marks.
- Sheryl told them, “You might be scared when you watch this movie”; still, I don’t think it’s scary enough to prevent you from watching it.
Semicolons are never used to join dependent to independent clauses.
A colon connects clauses that are closely linked in meaning or topic. Typically, the second clause continues or develops the thought of the first clause, or it contains an illustration or explanation of a topic in the first clause. If a complete sentence follows a colon, the first word of that sentence should be capitalized.
- Bill has 20 paintings on his wall: Ten of them he painted himself.
- The dictator was overthrown: The cruelty of his methods and the corruption of his government were finally exposed.
- Everything in his life seemed to be coming apart and collapsing: his marriage, his career, his confidence in himself.
- The economic sustainability of Bangladesh depends on three factors: the production of tea and rice, the export of garments, and foreign investment.
A colon is sometimes used to introduce dialogue or formal statements. In this case, the first word after the colon is capitalized.
- Julien could not help himself when the teacher asked him what was wrong: “There is no reason for all of us to be punished because Fred won’t stop acting silly in class!”
- If she wants my opinion, this is what I shall tell her: “You need to raise your own kids when they’re that little and stop leaving them in day care.”
A colon is used after the greeting in formal or business letters.
- Dear Mrs. Jackson:
- Dear Governor:
A colon is used to separate hours and minutes in statements of time.
- 8:15 A.M.
- 11:37 P.M.
The question mark
A question mark is used at the end of a sentence to signal a question; it can be a direct question, an interrogative series, or an expression of editorial doubt.
- When are you coming?
- Peter waved his hands while jumping up and down. What if they failed to see him?
- What do you think of his paintings? sculptures? drawings?
- Despite his participation in the 1934 riots (?), we do not know which organization he was marching with.
The exclamation point
An exclamation point or mark is used to signal an interjection, which is often associated with fear, surprise, shock, excitement, or disbelief. An exclamation point can also be used instead of a question mark to indicate that the overall emotion of a question is surprise, not interrogation.
- That’s amazing!
- He stops short, shoots, and scores!
- Did they really believe we were that stupid!
An apostrophe is used in one of two ways: to form a contraction (a shortened version of two words) or to express possession. Following are some common English contractions.
- cannot → can’t
- do not → don’t
- it is → it’s
- what is → what’s
- who is → who’s
In the same way that the apostrophe is used to replace letters that have been omitted, it can also be used to indicate that numbers have been omitted.
- 1990 → ’90
- 2008 → ’08
The following examples illustrate the use of the apostrophe to express possession.
- Damien’s car is really fast.
- Rosie’s roses are so pretty.
- The roller skates are Helen’s.
- Have the employees’ paychecks come in yet?
When an apostrophe is used to indicate joint ownership, only the last word has the apostrophe.
- My grandmother and grandfather’s paintings are in the attic.
- Bill and Peter’s car dealership is at the next intersection.
If joint ownership is not involved, each party has an apostrophe.
- Tim and Barbara’s pets (All the pets belong to both Tim and Barbara.)
- Tim’s and Barbara’s pets (Tim has his pets, and Barbara has hers.)
It’s is a contraction of it is, whereas its is a possessive pronoun.
- It’s the most complicated problem I’ve had to solve.
- Its art collection was lost in the fire.
Quotation marks are used for the title of a short work, to indicate direct quotations, to indicate a part of a large work, and to emphasize certain, often ironic words. Quotation marks indicate the direct comments of a speaker or remarks taken from written material.
- “The Raven” is the title of a poem written by Edgar Allan Poe. (TITLE OF A SHORT WORK)
- Mark Twain first became known for his short story “The Celebrated Jumping Frog of Calaveras County.” (TITLE OF A SHORT WORK)
- She said, “There they go again,” as the children raced back outside to play. (DIRECT QUOTATION)
- In an article from last week’s Economist, I read that “10% of the world’s population controls 90% of the wealth.” (DIRECT QUOTATION)
- “When Business Mergers No Longer Work” was an article published in the New Yorker. (PART OF A LONGER WORK)
- I agree, the theater play was so “entertaining” that I slept through most of it.
- His latest painting is proof of “his creative skills” and worth every cent of the $20 he wants for it.
Single quotation marks are used to enclose a quotation within another quotation. The first quote is noted in the standard way, with double quotation marks, and the embedded quote is noted with single quotation marks.
- In his speech, Charles brought up an interesting point: “If Adam Smith wrote that ‘the subjects of every state ought to contribute towards the support of the government, as nearly as possible, in proportion to their respective abilities,’ then why are people clamoring for a flat tax?”
The hyphen and the dash
A hyphen is used to divide or syllabify words at the end of a line when the word runs over to the beginning of the next line. It also connects individual words to form a compound word.
Hyphens cannot be used to divide one-syllable words: thought, through, weight, and so on. Hyphens can be used to divide words of two or more syllables.
If a word already contains a hyphen, it is generally syllabified using that hyphen.
- a mid-life crisis
- a cross-cultural conference
A number of everyday words and expressions are hyphenated: U.S. Social Security numbers (666-86-3454), telephone numbers (555-342-4536), and certain compound nouns (two-step) and adjectives (two-way). Following are examples of hyphenated everyday words.
- Yves Saint–Laurent
When dividing words at the end of a line, leave at least two letters at the end of the line and bring at least three letters down to the beginning of the next line.
A dash interrupts the flow of a sentence and sets a separate thought off from the rest of a sentence.
- If you find yourself in a dangerous situation, use the two Bs method—back off and breathe in—because otherwise you might panic.
- She was thinking of ways of running away—how could she have agreed to be part of this nonsense—but she was stuck.
Parentheses and brackets
Parentheses enclose explanatory material, supplemental material, or any added information that could clarify the text it refers to. They are placed at the beginning and end of the enclosed text.
- The museum demolition that began in 1993 (and ended in 1996) was a sad reminder of how suddenly historical buildings can be taken away.
Parentheses can be used in text references.
- The death toll of Hurricane Katrina was staggering (see Table 5.7).
Parentheses can be used to set off a list of elements.
- The green screen on your left indicates (1) the wind speed, (2) the outside temperature, (3) the atmospheric pressure, and (4) the humidity ratio.
Brackets enclose editorial comments and corrections.
- These painting copies [reproduced from the original artworks that burned in the fire of 1954] are listed as some of the most expensive art of the exposition.
- The students prefer Milton over him [Shakespeare].
- The president said, “The illiteracy level of our children are [sic] appalling.”
Brackets can also be used to replace a set of parentheses within a set of parentheses.
- During his trial, Fidel Castro stated, “None of you are entitled to condemn, you’ll see, history will absolve me!” (See Fidel Castro’s speech “History Will Absolve Me” [October 16, 1953].)