Punctuation can be thought of as a sign that warns the reader that he or she is approaching a change in direction in a sentence. A road sign on a highway warns a motorist that the road ahead is not a straight, divided highway with one-way traffic but two lanes of traffic with a short curve. Similarly, punctuation in a sentence warns the reader that the flow of words ahead may shift in an unexpected direction. Thus punctuation guides the reader to avoid misreading just as a road sign warns the driver to avoid misdirection.

The period is the most common punctuation mark. It is used at the end of an abbreviated word such as Dr. to indicate the word doctor or at the end of a sentence. When typing, you should space once after an abbreviation and twice after a period which ends a sentence. If you are typing a document with margins justified right and left, however, use only one space after a period and let the computer adjust the spacing.

ERROR: A common error many writers make is to join two sentences which are closely related in meaning and end the first sentence with a comma instead of a period:

• John is my best friend, I have known him for twelve years.

	CORRECTION: If the writer wishes to join these two sentences, he or she should use a semi-colon instead of a comma: John is my best friend; I have known him for twelve years.
	ANOTHER OPTION: Another option is to revise the sentence: I have known my best friend John for twelve years. I have known John, my best friend, for twelve years.

A comma is the punctuation mark used most often within a sentence. A comma is also the punctuation mark that people seem to have more trouble with. The reason for this difficulty is that commas can be used in a larger variety of ways than periods. In fact, some people have a tendency to read a sentence out loud and then place a comma every time they pause to breathe, swallow, or emphasize a word. This practice usually results in an overuse of the comma.

	The comma actually has very few uses, all of which can be summed up in this one general rule: Use a comma to prevent misreading.
	Use the comma in these five instances to prevent misreading: Items in a series Interruptions Introductions Afterthoughts Compound sentences

1. Use a comma to separate items in a series. Notice in the examples below that the series can be single words or phrases:

• I like cereal, bananas, and orange juice for breakfast.
  
• Pizza, spaghetti, and lasagna are three of my favorite foods.
  
• Rising early in the morning, working hard throughout the day, and relaxing in the evening are my plans for sleeping well at night.
• Caution: If you join only two items in a series with "and," "but," or "or," then you do not need any commas.
  • I like cereal and orange juice for breakfast.
  • Working hard throughout the day and relaxing in the evening are my plans for sleeping well at night.

2. Use a comma before and after a word or phrase which interrupts the flow of the sentence:

• John, one of my best friends from college, now lives in Siler City.

3. Use a comma after an introduction to the main idea of the sentence. Notice that the italicized word signals the introduction. Notice also that the sentence below would read differently if the comma were removed:

• After eating, I decided to walk along the shore.
• After I had been walking in the woods, I noticed that my shoes were covered with mud.
• Although I have not finished all my work, I will go to the movies with you.
• Because I have spent too much time dwelling on the past, I have missed some opportunities in the present.
• Even though I have never eaten here, I have heard the food is delicious.
• If I finish my work on time, I will go to the movies with you.
• Knowing that my family was safe, I was relieved. (Notice that the person who was relieved is the same person who knew that the family was safe.)
• Since I have finished my work on time, I will go to the movies with you.
• When I was walking through the peaceful woods, yesterday and all its trouble seemed far away.
• While I stood there watching, the little girl saw me and came running towards me.

4. Use a comma before an afterthought:

• I felt a sense of relief, knowing that my family was safe. (The meaning of this sentence is "I knew that my family was safe. Therefore, I felt a sense of relief.")
• American manufacturing companies are learning to speed up production, thus making themselves more competitive. (The meaning of this sentence is "American manufacturing companies are learning to speed up production. Speeding up production will make the companies more competitive.")
• Caution I: The phrase "such as" is used to connect a term to an example of that term. If "such as" appears directly between the term and the example, then you would not use a comma, but if words interrupt the term and the example, then you would use a comma:
  • Be sure to include vegetables such as broccoli and carrots in your diet.
  • Be sure to include vegetables in your diet, such as broccoli and carrots.
• Caution II: The pronouns "which" and "that" are used as conjuctions to introduce clauses that modify or describe a noun. "Which" introduces a non-restrictive clause that provides extra or non-essential descriptive information. "That" introduces a restrictive clause that provides essential information or description. In the following examples, do not use a comma with "that" since the clause that modifies "dog" is essential information that restricts the meaning of "dog" to a particular dog. Do use a comma with "which" since the clause that modifies the noun "dog" is extra, non-essential information:
  • I saw the dog that bit you.
  • I saw the dog that bit you, which is a collie.

5. Use a comma to join two sentences (compound sentence) with one of the "FANBOYS: for, and, nor, but, or, yet, and so (but not so that). Notice that the comma is used in each of the examples below to signal to the reader that the word in italics is introducing a new idea; otherwise, the word in italics would seem to belong to the first part of the sentence:

• Eat a diet rich in carbohydrates the day before the race, for the gold medal will be won by the runner who has plenty of energy.
  
• Take advantage of each opportunity, and you will always have more opportunities to take advantage of.
  
• Time does not wait for anyone, nor does the Internal Revenue Service.
  
• Being in the right place at the right time will not necessarily secure you the job, but not being in the right place at the right time will produce nothing.
  
• Be sure to eat your dessert first, or you may find that you will have no room after you eat the main course.
  
• I have always had a wonderful time traveling to other countries, yet I have always been glad to return home.
  
• Patience is supposed to be a virtue, so now I will be patient and see if I feel virtuous.

1. Use a semi-colon to join sentences that are related in meaning and to give each part of the the new sentence equal emphasis.
   1. Use a semi-colon to join two sentences without using any transitional word:
      
      • Eat a diet rich in carbohydrates the day before the race; the gold medal will be won by the runner who has plenty of energy.
      
      
   2. Use a semi-colon to join two sentences with a long transitional word such as however, therefore, and otherwise. In addition, use a comma after the transitional word because it interrupts the flow of the second sentence. Notice that although the meaning of the first part of the sentence stays the same, the second part of the sentence changes with different transitional words.
   
   
   • Eat a diet rich in carbohydrates the day before the race; however, don't eat so much that you can't sleep the night before.
     
   • Eat a diet rich in carbohydrates the day before the race; therefore, you will have plenty of energy to carry you through the race.
     
   • Eat a diet rich in carbohydrates the day before the race; otherwise, you may find that you have run out of energy before you have finished the race.
     
   • Note: Instead of being used between two sentences, however and the other transitional words listed above can be placed between the subject and verb of a sentence. In that type of sentence, use a comma before and after the transitional word:
     
   • Eat a diet rich in carbohydrates the day before the race; don't eat so much, however, that you can't sleep the night before.
     
   • Eat a diet rich in carbohydrates the day before the race; you will have plenty of energy, therefore, to carry you through the race.
   
   
2. Use a semi-colon to separate the items in a series when one or more of the items also contain items in a series. Notice that the following sentence would be difficult to read if commas were used instead of the semi-colons:
   
   • I prefer cereal, banana, milk, juice, and English muffins for breakfast; a turkey, cheese, lettuce, and tomato sandwich for lunch; and pasta, salad, rolls, and apple pie for dinner
   
   
3. Use a semi-colon between two independent clauses when the independent clauses themselves contain commas:
   • I have known Mr. Smith ever since I arrived in this town, or maybe I met him the year before; I can't remember for sure, but I am sure I have known him for the past five years.
   
   

Use the colon to introduce.

1. Use a colon to introduce a list only when a complete sentence precedes the list:
   • Healthy living usually includes the following:   a well-balanced diet, regular exercise, and rest.
   • Healthy living usually includes a well-balanced diet, regular exercise, and rest.
   
   
2. Use a colon to when a complete sentence introduces an explanatory word, phrase, or sentence that you want to emphasize:
   • Alexander Pope gave us good advice many years ago:   "Act well your part; there all the honor lies."

The English language is so flexible and varied that it permits several different ways of expressing ownership of, responsibility for, or possession of something or someone. Instead of saying, "The dented fender that belongs to John was the only injury in the wreck" or "John has a dented fender that was the only injury in the wreck," we can say, "John's dented fender was the only injury in the wreck." Notice in the last example that the word John ends in an apostrophe (') and an "s." Notice the similar use of the apostrophe and "s" in the following sentences. In each case the bolfaced word has ownership, possession of, or responsibility for the word or phrase which follows. When you proofread your own writing, check your sentences to see if you have used possessive nouns. Make sure they end in an apostrophe and an "s" as shown in the following examples:

• Summer's heat wave has finally ended. (The heat wave belongs to summer.)
  
• The man's overcoat is too large for my son. (The overcoat belongs to the man.)
  
• The men's club will meet on Wednesday. (The club belongs to the men.)
  
• The child's first day at school was filled with surprises. (The first day belongs to the child.)
  
• The woman's gloves were lying on the table. (The gloves belong to the woman.)
  
• The women's club will meet on Thursday. (The club belongs to the women.)
  
• The club's dues will be raised by fifty dollars. (The dues belong to the club.)
  
• The Joneses' party was a success. (The party belongs not to one person names Jones but to several Joneses.)
  
• The team's celebration was boisterous. (The celebration belongs to one team.)
  
• The teams' celebration was boisterous. (The celebration belongs to several teams.)
  
• Note: if the word already ends in an s, as shown in the second sentence above, simply add the apostrophe after the s to show that the entire word is the owner.

• Let's go to the party tonight. (Let us go to the party.)
  
• We can't go because we weren't invited. (We cannot go because we were not invited.)
  
• It's too bad that we weren't invited. (It is too bad that we were not invited.)
  
• Note: In the last example above, it's means it is. The word its is a possessive pronoun that means belonging to it, as in "the dog ate all its food." Possessive pronouns, such as its, yours, theirs, ours, his, and hers are not written with an apostrophe as possessive nouns are.
  

Use quotation marks around quotations and titles of chapters, poems, songs, stories, and articles. Use italics or underlining with the titles of books, magazines, newspapers, etc.

1. Use quotation marks around the title of a chapter from a book, of a poem from a book of poetry, or of a song from a record album.
   
2. Place the title of a story or article from a magazine or newspaper within quotation marks.
   
3. Use italics with the titles of books, magazines, newspapers, movies, record albums, and pamphlets. Note: If you do not have a typewriter or printer that can print in italics, underline the title.
   
   • "Fields of Gold" has been a hit song from Sting's recording Ten Summoner's Tales.
     
   • "Birches" can be found in Robert Frost's Complete Poems.
     
   • Did you read "In the Tracks of Thoreau" from the March 1981 issue of National Geographic?

1. Use the hyphen (-) to form compound words:
   • You should not drive your car over 60 miles per hour during the break-in period.
     
   • His attitude toward her problem was cold-hearted.
   
   
2. Use the hyphen (-) to divide words at the end of a line. Note: The word should be divided by syllables, so be sure to use a dictionary if you are not certain where the break should occur.
   • If you do not have enough room to write the entire word collapse at the end of a sentence, look up the word in your dictionary. You will see it written in this manner: col  lapse. This spelling means that at the end of the line you would write col-, and then write lapse at the beginning of the next line.
   
   
3. Use the hyphen (-) to form compound adjectives used in front of a noun. Note: The words are hyphenated because they are used as one. If the words are used after the noun, however, they do not have to be hyphenated.
   • That is a broken-down car. That car is broken down.
     
   • He is a soon-to-be father. He will be a father soon.
   • She is my headset-wearing, CD-toting, thirteen-year-old daughter. My daughter is thirteen years old, wears a headset, and carries her CD collection wherever she goes.
   
   

Use a dash before and after an interrupting word, phrase, clause, or sentence when you want to give extra emphasis to the interrupting words or whenever the interrupting words contain words or phrases separated by commas. The dash can be written in one of four ways:

1. Place a space before and after a hyphen - as you see here - and then continue.
   
2. Place two hyphens with no spaces before and after the interrupting phrase--as you see here--and then continue.
   
3. Place a space before and after an en dash – as you see here – and then continue.
   
4. Insert an em dash with no spaces before and after the interrupting words—as you see here—and then continue.

These are typical examples of the dash used for emphasis or to guide the reader through interruptions:

• The trip was — what a relief — finally over!
• Being cooped up in our old pink station wagon — with my parents, sister, and two brothers for six days of monotonous travel — was not something that I anticipated with enthusiasm.

Some writers like to use the single hyphen with spaces before and after to indicate a speaker who has interrupted his own flow of thoughts and then use double hyphens with a space before and after the hyphens to indicate that a speaker has been interrupted by someone else. You can also use the dash to signify interruptions in dialogue. Court reporters, for example, use the dash, when transcribing a speech during which either the speaker interrupts his or her own sentence or a second speaker interrupts the first speaker:

I have known Mr. Smith ever since I arrived in this town - or maybe I met him the year before; I can't remember for sure - but I am sure I have known him for the past five years.

I have known Mr. Smith ever since I arrived in this town -
--Was that in 1995?--
- no, that was in 1996 - but it may have been in 1995; I can't remember for sure.

Use parentheses when the interruption is extra information not essential to the meaning of the sentence. In transcribing speech, parentheses would seldom be used. Brackets, however, may be used to indicate that someone has entered a room during the middle of the speech:

I have known Mr. Smith ever since I arrived in this town [plaintiff's lawyer, Ms. Jones, entered the room] but maybe longer.