1. Conquering the Comma
Rationale: Welcome to “Conquering the Comma.” This presentation is designed to acquaint your students with the rules of comma usage, including placement in compound sentences, after introductory elements, with dependent phrases and clauses, around nonessential elements, in a series, and with adjectives. This presentation will also cover methods for avoiding a common comma error—the comma splice. The twenty-seven slides presented here are designed to aid the facilitator in an interactive presentation of the elements of comma usage. This presentation is ideal for the beginning of a composition course, the assignment of a writing project, or as a refresher presentation for grammar usage.
This presentation may be supplemented with OWL handouts, including “Using Commas” ( “Commas after Introductions” ( and “Commas with Non-essential Elements” (
Directions: Each slide is activated by a single mouse click, unless otherwise noted in bold at the bottom of each notes page.
Writer and Designer: Jennifer Liethen Kunka
Contributors: Muriel Harris, Karen Bishop, Bryan Kopp, Matthew Mooney, David Neyhart, and Andrew Kunka
Developed with resources courtesy of the Purdue University Writing Lab
Grant funding courtesy of the Multimedia Instructional Development Center at Purdue University
© Copyright Purdue University, 2000.

2. What Is a Comma?
A comma is a punctuation mark that indicates a pause is needed in a sentence.
Commas help to clarify meaning for the reader. ,
Key Concepts: The facilitator may choose to invite the audience to respond to the title question and allow participants to discuss the function of the comma. Many writers become frustrated with comma usage because they are unsure of where to place them in their sentences. This presentation is designed to demystify the placement and usage of commas.
The facilitator may stress to participants that commas should not be ignored in writing; they are often needed to clarify meaning within a sentence and can help to avoid confusion.
Click mouse after title question to reveal each response.

3. Clauses and Phrases
A clause is a group of words that contains both a subject and a verb that complement each other.
A phrase is a group of words that does not contain a subject or a verb that complement each other.
Key Concepts: This slide articulates the basic differences between a clause and a phrase. The facilitator may stress the importance of understanding these definitions for understanding comma placement.

4. Sentence Structure: Independent Clause
A complete sentence has two components, a subject and a verb.
The subject and verb must form a complete thought to be considered an independent clause.
Key Concepts: This slide explains the structure of an independent clause, the primary building block for the development of any sentence. An independent clause requires a subject and a verb that can stand as a complete thought. Sentences can be very short, as the one detailed in the slide. The facilitator may ask the audience to identify the subject and verb in the example.
Click mouse after text appears to reveal picture and sample sentence.
Click mouse after sample sentence to reveal the labels “subject” and “verb.”
The couple dances.
The couple dances.
subject (S) verb (V)

5. Sentence Structure: Compound Sentence
A sentence that contains two independent clauses joined by a coordinating conjunction is called a compound sentence.
A conjunction joins words, phrases, and clauses together in a sentence.
Conjunctions
for
and
nor
but or
yet so
Key Concepts: This slide explains the structure of a compound sentence and the role of a conjunction. An easy method for remembering the seven coordinating conjunctions is the acronym “fan boys.”
Click mouse at the end of the first column.
Click mouse at the end of the conjunction list to reveal the acronym.
FAN BOYS

6. Sentence Structure: Compound Sentence
The comma in a compound sentence is placed before the coordinating conjunction.
Andy built a snowman, and Jeff played with his dog.
S V conj.
Andy built a snowman, and
Jeff played with his dog.
S V
Example: This slide exemplifies the location of a comma in a compound sentence, before the coordinating conjunction. The facilitator may ask participants to identify the subjects, verbs, and conjunction in the example.
Click after example sentence appears to reveal parts of speech.

7. Sentence Structure: Compound Sentence
Where would you place the comma in the following sentence?
Example: This slide provides participants with an opportunity to locate the correct position for the comma within the sample sentence. The facilitator may also invite students to identify the subjects, verbs, and conjunction in the sentence.
Click mouse after sample sentence to reveal the comma.
Click mouse after the comma to reveal parts of speech.
Dan struggled with his homework so his father helped him.
Dan struggled with his homework, so his father helped him.
S V conj. S V

8. Sentence Structure: Dependent Clause
Some dependent
clause markers:
A dependent clause contains a subject and verb, but the clause cannot stand independently.
Dependent clauses can often be identified by the use of dependent clause markers.
because
since
when
while
until if as
though
although
unless
after
before
once
whether
Key Concepts: This slide explains the definition of a dependent clause. The dependent clause markers can help writers identify clauses that cannot stand alone within a sentence.

9. Sentence Structure: Dependent Phrases and Clauses
Dependent phrases and clauses help to clarify and add detail to an independent clause.
Dependent clauses may appear at the beginning, middle, or end of a sentence.
Key Concepts: This slide further clarifies the role of dependent phrases and clauses within a sentence.

10. Introductory clause= dependent clause located at the beginning of a sentence
When a dependent clause is placed at the beginning of a sentence, place a comma between the independent clause and the dependent clause.
Key Concepts: An introductory clause is a dependent clause located at the beginning of a sentence. After an introductory clause, a comma is needed to distinguish it from the independent clause.
Activity: The facilitator may choose to ask students to identify the independent and dependent clauses, the subjects, the verbs, and the dependent clause marker in the sample sentence.
Click mouse to reveal the parts of speech.
When Elizabeth called 911, the firemen rushed to her rescue.
When Elizabeth called 911, the firemen rushed to her rescue. DCM S V S V

11. Where would you place the comma in the following examples?
Introductory Clause
Where would you place the comma in the following examples?
Since it was raining, we decided to go to the movies. DCM S V S V
Since it was raining we decided to go to the movies.
Once the movie began, I fell asleep.
DCM S V S V
Once the movie began I fell asleep.
Activity: This interactive slide invites participants to place commas after the introductory clauses in each sentence. Again, the facilitator may ask students to identify the parts of speech in each example.
Click mouse to reveal parts of speech, and then click again to reveal each example.
After the movie ended, we went out for coffee.
DCM S V S V
After the movie ended we went out for coffee.

12. Dependent Clauses When a dependent clause is
located after an independent clause,
DO NOT place a comma between the two.
I went on the roller coaster because my brother dared me.
S V DCM S V
Activity: When a dependent clause follows an independent clause, commas are not used. Facilitators may choose to ask students to identify the parts of speech in each example.
I became very sick when the
S V DCM
roller coaster zoomed upside down.
S V

13. Sentence Structure: Essential Phrases and Clauses
An essential clause or phrase is used to modify a noun.
It also adds information that is critical to the meaning of the sentence.
Essential clauses are NOT set off by commas.
Key Concepts: This slide leads off a section about essential and non-essential phrases and clauses. Essential phrases and clauses—elements that add critical information to the meaning of a sentence—do not have commas placed around them.

14. Sentence Structure: Essential Phrases and Clauses
The people who work in my office are so uptight!
Example: This example illustrates the placement of an essential phrase within a sentence. The phrase “who work in my office” is critical to the overall meaning of the sentence; therefore, it should not be set off with commas.
If the clause or phrase is eliminated from the sentence and the sentence no longer makes sense, the clause or phrase is essential.
S essential phrase V
Without the essential phrase, this sentence does not make complete sense : The people are so uptight!

15. Sentence Structure: Essential Phrases and Clauses
The martini that I had at Joe’s was much better than this one!
Key Concept: The word “that” almost always indicates an essential phrase or clause.
S essential V
The word “that” is almost always an indicator of an essential phrase or clause.

16. Sentence Structure: Nonessential Phrases and Clauses
A nonessential phrase or clause adds extra information to a sentence.
This information can be eliminated from the sentence without jeopardizing the meaning of the sentence.
Always place commas around nonessential phrases and clauses.
Key Concepts: This slide illustrates the difference between essential and nonessential elements. While commas should not be placed around essential phrases and clauses, they should be placed around nonessential phrases and clauses.

17. Sentence Structure: Nonessential Phrases and Clauses
My brother, who lives across town, plans to throw a party!
Example: Nonessential phrases and clauses can be removed from sentences without jeopardizing the overall meaning of a sentence. In this example, “who lives across town” is superfluous information; it is not critical to the main message of the sentence—the woman’s brother will throw a party for her.
S non-essential V
Even without the phrase the sentence still makes sense : My brother plans to throw a party!

18. Sentence Structure: Nonessential Phrases and Clauses
S V
Steve said that he would propose to me on Valentine’s Day, which is my favorite holiday!
Example: This slide provides another example illustrating the placement of a nonessential phrase within a sentence. At the end of a sentence, the nonessential element should have a comma placed before it and a period after it. The facilitator may wish to stress that “which” often, but not always, indicates a nonessential phrase or clause.
non-essential
Use commas to set off additional information

19. Would you place commas in the following sentences? If so, where?
I am planning a trip to Paris, which is one of the greatest cities in the world.
I am planning a trip to Paris which is one of the greatest cities in the world.
The place that I would most like to see is the Eiffel Tower.
Activity: These examples allow participants an opportunity to test their comma skills.
The first example needs a comma after “Paris” to set off the nonessential phrase.
The second example requires no comma. The phrase “that I would most like to see” is essential to the meaning of the sentence. The sentence will not make sense without this essential phrase.
The third example requires two commas, both before and after the nonessential phrase “who is one of my business contacts.” The main message of this sentence—that Pierre will meet this person at the airport—is clear without knowing the additional information about his identity.
Click to reveal the comma placement for each example.
No comma is needed. The sentence is correct.
Pierre, who is one of my business contacts, will meet me at the airport.
Pierre who is one of my business contacts will meet me at the airport.

20. Sentence Structure: Commas in a Series
Place commas in a sentence to divide items in a list.
The commas will help the reader to avoid confusion.
The comma before the conjunction is generally required, but it can be omitted if there is no possibility of confusion.
Key Concept: Commas should be placed between each element within a list. This placement can help the reader to avoid confusion.

21. Sentence Structure: Commas in a Series
Consider the difference in the following:
Last month, Alex dated Mary Ann Lee and Kim.
Last month, Alex dated Mary, Ann, Lee, and Kim.
Last month, Alex dated Mary Ann, Lee, and Kim.
Activity: These examples illustrate the importance of comma placement within a list. The facilitator may ask students to answer the question “How many women did Alex date?” in accordance with each example—two women in the first, four in the second, and three in the third.
Click to reveal each example.
How many women did Alex date?

22. Sentence Structure: Commas in a Series
Commas should be placed in series of words, phrases, or clauses.
Place commas in the following sentences:
Martina brushed her hair, put on her pajamas, and went to bed.
Martina brushed her hair put on her pajamas and went to bed.
Activity: The facilitator may stress to participants that a series includes a list of words, but it can also include a list of phrases or clauses. This exercise allows participants to determine when the commas should be placed in each sentence.
Click to reveal commas for each sentence.
She fell asleep and dreamed that she was a princess, she kissed a frog, and she rescued her prince.
She fell asleep and dreamed that she was a princess she kissed a frog and she rescued her prince.

23. Commas with adjectives
Use commas to separate adjectives that provide an equal description of a noun.
THE TEST:
Can you put “and” between the adjectives?
Can they be described in reverse order?
If so, use a comma.
Key Concepts: Students often find comma placement between adjectives to be tricky. The key is to determine if the adjectives are equal—meaning that they modify the noun in the same capacity. Adjectives of size and quantity are generally considered to be unequal to adjectives of character or quality. Placing “and” between adjectives or reversing the order of adjectives are good tests to determine if a comma is needed.
big blue house three hungry kittens
a cranky, ungrateful man

24. A Common Comma Error: The Comma Splice
A comma splice is an error in which two independent clauses are joined by a comma.
We had a nice time, I hope we can meet again soon.
S V S V
Key Concepts: One of the most prevalent comma errors is the comma splice—the placement of a comma between two independent clauses.
The Internet has revolutionized the business world,
S V
online sales have increased dramatically this year.
S V

25. To Correct a Comma Splice
Insert a conjunction between the two independent clauses.
Start a new sentence.
Insert a semi-colon between the two independent clauses (only in cases where the independent clauses are closely related in topic).
Key Concepts: This slide enumerates several methods for correcting comma splices. The examples listed here are corrections of the comma splices in the previous slide.
We had a nice time, and I hope we can meet again soon.
We had a nice time. I hope we can meet again soon.
The Internet has revolutionized the business world; online sales have increased dramatically this year.

26. How would you correct the following sentences?
This semester I am taking calculus physics and economics.
This semester I am taking calculus, physics, and economics.
Calculus is my best subject, I am certain I will get an A.
Calculus is my best subject, and I am certain I will get an A.
Although I am very busy, I still find time to have fun.
Although I am very busy I still find time to have fun.
Activity: This slide invites participants to again test their comma skills.
The first example requires commas between each element within the list.
The second example contains a comma splice. The sentence may be corrected by the addition of a conjunction after the comma, turning the comma splice into a compound sentence. This example may also be corrected by separating the two clauses into two separate sentences, or by changing the comma to a semi-colon.
The third example requires a comma after the introductory clause. The facilitator may wish to note that “although” is a dependent clause marker.
The fourth example, a compound sentence, requires a comma before the conjunction. Commas are also needed after each element in the list.
Click mouse to reveal comma placement for each example.
Last weekend my brother visited me and we went to a football game a party and a rock concert.
Last weekend my brother visited me, and we went to a football game, a party, and a rock concert.