1. Use a comma to join independent clauses with a coordinating
conjunction: for, and, nor, but, or, yet, so:
We visited the museum, but we never found
the sculpture garden.
Susan lost her keys, yet she still made it to class on time.
2. Use a comma after an introductory clause, or after an introductory phrase of five words or more:
Introductory Clause: As the days grow longer, we find ourselves restless to be outdoors.
Introductory Phrase: In most middle class American households, dinners prepared by microwave are commonplace.
Introductory clauses are most often subordinate elements of the sentence. This means that they cannot stand on their own, and that they support the meaning of the main clause.
A conjunctive adverb or transition element is set off by a comma. These elements signal a logical direction of the sentence content. This direction may be a continuation as in the following sentence:
For example, Americans spend more on
prepared foods
than on fresh vegetables.
Or, they may signal a logical contrast:
However, we still like to think of ourselves as healthy.
3. Use a comma after all items in a series:
The junior class took reponsibility for the
homecoming parade,
the holiday tea, and the spring cruise.
4. Use a comma to set off nonrestrictive (nonessential) elements of a sentence:
Alana, a senior from Texas, spoke to our
class
about her mission work in Cuba.
Nonrestrictive elements can be subordinate clauses or phrases. They can also be appositives such as "a senior from Texas" above. Appositives are words, clauses, or phrases which offer additional information about the sentence element that proceeds them.
1. Do not use a comma to separate compound elements within a single clause or phrase:
Incorrect: Four Meredith students entered the national
contest, and won first place.
The comma in this example separates the two parts of a compound verb, "entered" and "won." There is only one clause in the sentence. If the second verb, "won," were to have its own subject, then a comma would be needed:
Correct: Four Meredith students entered the national
contest, and they won first place.
2. Do not use a comma before the first or after the last item in a series:
Incorrect: She asked me to bring, crackers, napkins, and ice.
The comma after "bring" should be removed.
Correct: She asked me to bring crackers, napkins, and ice.
Incorrect: She asked me to bring crackers, napkins, and, ice.
The comma after "and" should be removed.
Correct: She asked me to bring crackers, napkins, and ice.
3. Do not use a comma with restrictive (essential) clauses or phrases:
Incorrect: Virginia Woolf's novel, To the Lighthouse, explores the passing of time.
By setting the title of the novel off with commas, we indicate that To the Lighthouse is the only novel Virginia Woolf wrote.
Correct: Virginia Woolf's novel To the Lighthouse explores the passing of time.
In this form, the restrictive element To the Lighthouse tells us which of Virginia Woolf's numerous novels explores the passing of time.
4. Do not use a comma to separate the subject and verb of a sentence:
Incorrect: The ways in which people choose to communicate, have been linked to gender expectations.
The subject is "ways"; the verb is "have been linked." The phrase "in which people choose to communicate" is essential to the understanding of "ways," so it does not call for a comma at either end. This problem occurs most often when a group of words appears between the subject and the verb. The sentence should look like this:
Correct: The ways in which people choose to communicate have been linked to gender expectations.
5. Do not join independent clauses with a comma:
Incorrect: Sonya received three job offers, she took the one closest to home.
This is a comma splice. It can be punctuated correctly with a semicolon:
Correct: Sonya received three job offers; she took the one closest to home.
The sentence can also be edited to include a coordinating conjunction:
Correct: Sonya received three job offers, and she took the one closest to home.
It is also correct to remove the subject "she" and make a compound verb:
Correct: Sonya received three job offers and took the one closest to home.
For more help with comma splices, please see the "Sentence Problems" section of this guide.
Comma Tutorial
One of the three sentences in each group uses commas correctly. Click on the corresponding colored block to see if you have chosen the right one. Then roll over the comments box for an explanation.
1. Use a semicolon to connect closely related independent clauses not joined by a coordinating conjunction:
Diane expects to get a car for her birthday; she's
already
making plans for a trip.
Her parents' prosperity has made her independent; her independence has made her strong.
Note that on either side of the semicolon you will find an independent clause, complete with subject and verb.
2. Use a semicolon between independent clauses linked by a conjunctive adverb or a transitional phrase:
Special effects can interfere with our sense of a
film's story line;
however, we still rush to the theater for the latest in laser wars and
technographics.
Remember the comma after "however," the conjunctive adverb.
I really enjoyed Kenneth Brannaugh's Hamlet;
even so, the Mel Gibson version captures the story without dragging on too long.
Examples of transitional phrases: after all, as a matter of fact, as a result, at any rate, at the same time, for example, finally, likewise, otherwise
3. Use a semicolon between items in a series containing internal punctuation. For example, items in a series may include commas:
My favorite film adaptations of Shakespeare
include the 1950s version of Hamlet, starring Lawrence Olivier;
Brannaugh's Much
Ado about Nothing, starring his ex-wife Emma Thompson, and the recently release Othello,
which featured Denzel Washington in the title role.
1. Do not use a semicolon to join sentence elements of unequal rank. Semicolons do not connect clauses and phrases, nor do they connect subordinate clauses to the main clause in a sentence.
Incorrect: Tired of waiting for an operator; Sheila hung up the telephone.
A comma should be used to connect the introductory phrase to the main clause.
Correct: Tired of waiting for an operator, Sheila hung up the telephone.
Incorrect: Although the cost of living has remained even; basic expenses can still devour a student's paycheck.
The "although" clause is dependent upon the main clause. The sentence should be punctuated as follows:
Correct: Although the cost of living has remained even, basic expenses can still devour a student's paycheck.
1. Use a colon after an independent clause to direct attention to a list, an appositive or a quotation. Note that the sentence element after the colon is not an independent clause.
Introducing a list: Maisie had three goals: to win a poetry prize, to travel to Asia, and to learn to snowboard.
Introducing an appositive: Carmen told us about her trip: six weeks of rock climbing in Afganistan.
Introducing a quotation: Officer Melbourne offered this advice: "After a snowstorm, drive slowly and avoid steep inclines."
2. Use a colon to connect two independent clauses IF the second summarizes or explains the first:
Example: Patience is a virtue: it can make you a kinder person.
1. Do not use a colon between a verb and its complement or
object:
Incorrect: The most difficult challenges I have faced include: overcoming a fear of water and learning to walk again after breaking both ankles.
Note that the portion of the sentence to the left of the colon is not an independent clause. The "list" is the object of the verb "include." This sentence would be correct without the colon:
Correct: The most difficult challenges I have faced include overcoming a fear of water and learning to walk again after breaking both ankles.
Punctuation Tutorial
This tutorial allows you to check your understanding of the use of commas, semicolons and colons. It is helpful to know when not to use a semicolon. Click on the colored box beside the number of the correctly punctuated sentence.
