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 thirty-one slide 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 resources here:
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
Updated by H. Allen Brizee, 2007.
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, 2007.

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.
The couple dances.
subject (S) verb (v)
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.

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
F A N B O Y S
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.”

6. Sentence Structure: Compound Sentences
The comma in a compound sentence is placed before the coordinating conjunction.
S V Conj. S V
Andy built a snowman, and Jeff played with his dog.
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.

7. Sentence Structure: Compound Sentence
Where would you place the comma in the following sentence?
S V S
Dan struggled with his homework so his father V
helped him.
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.

8. Sentence Structure: Dependent Clause
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.
Some 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 & 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. Sentence Structure: Introductory Clause
When a dependent clause is placed at the beginning of a sentence, place a comma between the independent clause and the dependent clause.
Dep. clause S V
Before he took the test, Dan struggled with
Conj S V
his homework, so his father helped him.
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.

11. Introductory Clause
Where would you place the comma in the following example?
S V
Because it was raining we decided to go to the movies.
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 the example.

12. Introductory Clause
Where would you place the comma in the following example?
Introductory clause S V
Because it was raining, we decided to go to the movies.

13. Dependent Clause When a dependent clause is
located after an independent clause,
Do not place a comma between the two.
S V
We decided to go to the movies because we were bored.
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 the example.

14. 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.
S essential phrase V
The people who work in my office are loud.
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. For the slide example: Without the essential phrase, this sentence does not make complete sense : The people are loud! While the sentence is grammatically correct, we don’t know about the people being discussed.

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

16. Sentence Structure: Nonessential Phrases & 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 & Clauses
Even without the phrase the sentence still makes sense: My brother plans to throw a party.
S non-essential V
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.

18. Sentence Structure: Nonessential Phrases & Clauses
Use commas to set off additional information.
S V
Steve said that he would propose to me on
non-essential
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.

19. Comma Practice
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.
The place that I would most like to see is the Eiffel Tower.
Pierre, who is one of my business contacts, will meet me at the airport.
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.

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.
How many women did Alex date?
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.

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.
She fell asleep and dreamed that she was a princess she kissed a frog and she rescued her prince.
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.

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.
big blue house | three hungry kittens | a cranky, bald man
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.

24. A Common Error: The Comma Splice
A comma splice is an error in which two independent clauses are joined by a comma.
S V
Dan struggled with his homework, his
father helped him.
Key Concepts: One of the most prevalent comma errors is the comma splice—the placement of a comma between two independent clauses.

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 in the next three slides are corrections of the comma splices in the previous slide.

26. To Correct a Comma Splice
S V Conj.
Dan struggled with his homework, so his
S V
father helped him.
Add a coordinating conjunction.

27. To Correct a Comma Splice
S V
Dan struggled with his homework. His
father helped him.
Start a new sentence.

28. To Correct a Comma Splice
S V
Dan struggled with his homework; his
father helped him.
Insert a semi-colon between the two independent clauses (only in cases where the independent clauses are closely related in topic).

29. Comma Splice Practice How would you correct the following?
This semester I am taking calculus physics and economics.
Calculus is my best subject, I am certain I will get an A.
Although I am very busy, I still find time to have fun.
Last weekend my brother visited me and we went to a football game a party and a rock concert.
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.

30. Additional Help Purdue University Writing Lab, Heavilon 226
Check our web site:
brief questions:
Rationale: As the presentation concludes, the facilitator can remind students that they can come to the Writing Lab for extra help with comma usage.
Click mouse after the title question.
For additional assistance with comma usage, see:
Harris, Muriel. Prentice Hall Reference Guide to Grammar and Usage. 4th ed. Upper Saddle River, NJ: Prentice Hall, 2000.

31. The End
Thanks!