语言教学 | 普渡大学写作教学系列General Writing 77-Punctuation
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Brief Overview of Punctuation
When speaking, we can pause or change the tone of our voices to indicate emphasis. When writing, we use punctuation to indicate these places of emphases. This handout should help to clarify when and how to use various marks of punctuation.
Independent clause: a clause that has a subject and a verb and can stand alone; a complete sentence
Dependent clause: a clause that has a subject and a verb but cannot stand alone; an incomplete sentence
Comma
Use a comma to join two independent clauses and a coordinating conjunction (and, but, or, for, nor, so).
Road construction can be inconvenient, but it is necessary.
The new house has a large fenced backyard, so I am sure our dog will enjoy it.
Use a comma after an introductory phrase, prepositional phrase, or dependent clause.
To get a good grade, you must complete all your assignments.
Because Dad caught the chicken pox, we canceled our vacation.
After the wedding, the guests attended the reception.
Use a comma to separate elements in a series. Although there is no set rule that requires a comma before the last item in a series, it seems to be a general academic convention to include it. The examples below demonstrate this trend.
On her vacation, Lisa visited Greece, Spain, and Italy.
In their speeches, many of the candidates promised to help protect the environment, bring about world peace, and end world hunger.
Use a comma to separate nonessential elements from a sentence. More specifically, when a sentence includes information that is not crucial to the message or intent of the sentence, enclose it in or separate it by commas.
John's truck, a red Chevrolet, needs new tires.
When he realized he had overslept, Matt rushed to his car and hurried to work.
Use a comma between coordinate adjectives (adjectives that are equal and reversible).
The irritable, fidgety crowd waited impatiently for the rally speeches to begin.
The sturdy, compact suitcase made a perfect gift.
Use a comma after a transitional element (however, therefore, nonetheless, also, otherwise, finally, instead, thus, of course, above all, for example, in other words, as a result, on the other hand, in conclusion, in addition)
For example, the Red Sox, Yankees, and Indians are popular baseball teams.
If you really want to get a good grade this semester, however, you must complete all assignments, attend class, and study your notes.
Use a comma with quoted words.
"Yes," she promised. Todd replied, saying, "I will be back this afternoon."
Use a comma in a date.
October 25, 1999
Monday, October 25, 1999
25 October 1999
Use a comma in a number.
15,000,000
1614 High Street
Use a comma in a personal title.
Pam Smith, MD
Mike Rose, Chief Financial Officer for Operations, reported the quarter's earnings.
Use a comma to separate a city name from the state.
West Lafayette, Indiana
Dallas, Texas
Avoid comma splices (two independent clauses joined only by a comma). Instead, separate the clauses with a period, with a comma followed by a coordinating conjunction, or with a semicolon.
Semicolon
Use a semicolon to join two independent clauses when the second clause restates the first or when the two clauses are of equal emphasis.
Road construction in Dallas has hindered travel around town; streets have become covered with bulldozers, trucks, and cones.
Use a semicolon to join two independent clauses when the second clause begins with a conjunctive adverb (however, therefore, moreover, furthermore, thus, meanwhile, nonetheless, otherwise) or a transition (in fact, for example, that is, for instance, in addition, in other words, on the other hand, even so).
Terrorism in the United States has become a recent concern; in fact, the concern for America's safety has led to an awareness of global terrorism.
Use a semicolon to join elements of a series when individual items of the series already include commas.
Recent sites of the Olympic Games include Athens, Greece; Salt Lake City, Utah; Sydney, Australia; Nagano, Japan.
Colon
Use a colon to join two independent clauses when you wish to emphasize the second clause.
Road construction in Dallas has hindered travel around town: parts of Main, Fifth, and West Street are closed during the construction.
Use a colon after an independent clause when it is followed by a list, a quotation, an appositive, or other ideas directly related to the independent clause.
Julie went to the store for some groceries: milk, bread, coffee, and cheese.
In his Gettysburg Address, Abraham Lincoln urges Americans to rededicate themselves to the unfinished work of the deceased soldiers: "It is for us the living rather to be dedicated here to the unfinished work which they who fought here have thus far so nobly advanced. It is rather for us to be here dedicated to the great task remaining before us — that from these honored dead we take increased devotion to that cause for which they gave the last full measure of devotion — that we here highly resolve that these dead shall not have died in vain, that this nation under God shall have a new birth of freedom, and that government of the people, by the people, for the people shall not perish from the earth."
I know the perfect job for her: a politician.
Use a colon at the end of a business letter greeting.
To Whom It May Concern:
Use a colon to separate the hour and minute(s) in a time notation.
12:00 p.m.
Use a colon to separate the chapter and verse in a Biblical reference.
Matthew 1:6
Parenthesis
Parentheses are used to emphasize content. They place more emphasis on the enclosed content than commas. Use parentheses to set off nonessential material, such as dates, clarifying information, or sources, from a sentence.
Muhammed Ali (1942-2016), arguably the greatest athlete of all time, claimed he would "float like a butterfly, sting like a bee."
Dash
Dashes are used to set off or emphasize the content enclosed within dashes or the content that follows a dash. Dashes place more emphasis on this content than parentheses.
Perhaps one reason why the term has been so problematic—so resistant to definition, and yet so transitory in those definitions—is because of its multitude of applications.
In terms of public legitimacy—that is, in terms of garnering support from state legislators, parents, donors, and university administrators—English departments are primarily places where advanced literacy is taught.
The U.S.S. Constitution became known as "Old Ironsides" during the War of 1812—during which the cannonballs fired from the British H.M.S. Guerriere merely bounced off the sides of the Constitution.
To some of you, my proposals may seem radical—even revolutionary.
Use a dash to set off an appositive phrase that already includes commas. An appositive is a word that adds explanatory or clarifying information to the noun that precedes it.
The cousins—Tina, Todd, and Sam—arrived at the party together.
Quotation Marks
Use quotation marks to enclose direct quotations. Note that commas and periods are placed inside the closing quotation mark, and colons and semicolons are placed outside. The placement of question and exclamation marks depends on the situation.
He asked, "When will you be arriving?" I answered, "Sometime after 6:30."
Use quotation marks to indicate the novel, ironic, or reserved use of a word.
History is stained with blood spilled in the name of "justice."
Use quotation marks around the titles of short poems, song titles, short stories, magazine or newspaper articles, essays, speeches, chapter titles, short films, and episodes of television or radio shows.
"Self-Reliance," by Ralph Waldo Emerson
"Just Like a Woman," by Bob Dylan
"The Smelly Car," an episode of Seinfeld
Do not use quotation marks in indirect or block quotations.
Italics
Underlining and italics are often used interchangeably. Before word-processing programs were widely available, writers would underline certain words to indicate to publishers to italicize whatever was underlined. Although the general trend has been moving toward italicizing instead of underlining, you should remain consistent with your choice throughout your paper. To be safe, you could check with your teacher to find out which he/she prefers. Italicize the titles of magazines, books, newspapers, academic journals, films, television shows, long poems, plays of three or more acts, operas, musical albums, works of art, websites, and individual trains, planes, or ships.
Time
Romeo and Juliet by William Shakespeare
The Metamorphosis of Narcissus by Salvador Dali
Amazon.com
Titanic
Italicize foreign words.
Semper fi, the motto of the U.S. Marine Corps, means "always faithful."
Italicize a word or phrase to add emphasis.
The truth is of utmost concern!
Italicize a word when referring to that word.
The word justice is often misunderstood and therefore misused.
Punctuation in Types of Sentences
Learning rules for how and when to punctuate a sentence can be difficult, especially when you consider that different types of sentences call for different types of punctuation. This handout should help to clarify not only the types of sentences, but also what punctuation to use in what situation.
Punctuation in Types of Sentences
Independent clause: a clause that has a subject and a verb and can stand alone; a complete sentence
Dependent clause: a clause that has a subject and a verb but cannot stand alone; an incomplete sentence
Simple: composed of 1 independent clause.
No standard punctuation.
Compound: composed of 2 or more independent clauses.
Join 2 independent clauses by a comma and a coordinating conjunction (and, but, or, for, nor, so).
Road construction can be inconvenient, but it is necessary.
Join 2 independent clauses by a colon when you wish to emphasize the second clause.
Road construction in Dallas has hindered travel around town: parts of Main, Fifth, and West Street are closed during the construction.
Join 2 independent clauses by a semicolon when the second clause restates the first or when the two clauses are of equal emphasis.
Road construction in Dallas has hindered travel around town; streets have become covered with bulldozers, trucks, and cones.
Complex: composed of 1 or more dependent clauses and 1 or more independent clauses.
Join an introductory dependent clause with the independent clause by a comma.
Because road construction has hindered travel around town, many people have opted to ride bicycles or walk to work.
Many people have opted to ride bicycles or walk to work because road construction has hindered travel around town.
Compound-Complex: composed of 1 or more dependent clauses and 2 or more independent clauses.
Join an introductory dependent clause with an independent clause with a comma. Separate 2 independent clauses with a comma and a coordinating conjunction (and, but, or, for, nor, so).
When it is filtered, water is cleaner, and it tastes better.
Join an introductory dependent clause with an independent clause with a comma. Separate 2 independent clauses by a colon when you wish to emphasize the second clause.
Whenever it is possible, you should filter your water: filtered water is cleaner and tastes better.
Join an introductory dependent clause with an independent clause with a comma. Separate 2 independent clauses by a semicolon when the second clause restates the first or when the two clauses are of equal emphasis.
When it is filtered, water is cleaner and tastes better; all things considered, it is better for you.