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.
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.
Clauses
Dependent Independent
4. Sentence Structure:
Independent Clauses
A complete sentence has at least two components, a
subject and a verb.
The subject and verb must form a complete thought to be
considered an independent clause.
5. Sentence Structure:
Compound Sentences
Compound Sentence: a sentence that contains two
independent clauses joined by a coordinating conjunction
A conjunction joins words, phrases, and clauses together
in a sentence.
Conjunctions (remember with the acronym FANBOYS):
8. Sentence Structure:
Dependent Phrases
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:
9. Sentence Structure:
Dependent Phrases
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.
12. Dependent Clauses
When a dependent clause is located after an independent
clause, do not place a comma between the two.
13. An essential clause or phrase is used to modify a noun. It
adds information that is critical to the meaning of the
sentence.
Essential clauses are not set off by commas.
Essential Phrases and
Clauses
14. The word “that” is almost always an indicator of an
essential phrase or clause.
Essential Phrases and
Clauses
15. A nonessential clause or phrase adds extra information
to a sentence. This information can be eliminated from the
sentence without influencing the meaning of the sentence.
Always place commas around nonessential phrases and
clauses.
Non-essential Phrases
and Clauses
16. Use commas to set off additional information:
Non-essential Phrases
and Clauses
17. 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.
Comma Practice
18. 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.
Sentence Structure:
Commas in a Series
19. 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?
Sentence Structure:
Commas in a Series
20. 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.
21. 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 yes, use a comma.
Commas with Adjectives
22. A comma splice is an error in which two independent clauses
are joined by a comma.
A Common Error:
The Comma Splice
23. Insert a conjunction between the two independent clauses
Start a new sentence
Insert a semi-colon between the two independent clauses
To Correct a
Comma Splice
24. 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.
To Correct a
Comma Splice
25. Where to Go
for More Help
Purdue University Writing Lab, Heavilon 226
Check our web site: http://owl.english.purdue.edu
Email brief questions to OWL Mail:
https://owl.english.purdue.edu/contact/owlmailtutors
26. The End
CONQUERING THE COMMA
Purdue OWL staff
Brought to you in cooperation with the Purdue Online Writing Lab
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.
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.
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.
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.”
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.
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.
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.
Key Concepts: This slide further clarifies the role of dependent phrases and clauses within a sentence.
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.
Activity: Click to reveal answer.
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.
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.
Key Concept: The word “that” almost always indicates an essential phrase or clause.
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.
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.
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.
Key Concept: Commas should be placed between each element within a list. This placement can help the reader to avoid confusion.
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.
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.
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.
Key Concepts: One of the most prevalent comma errors is the comma splice—the placement of a comma between two independent clauses.
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.
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.
Rationale: As the presentation concludes, the facilitator can remind students that they can come to the Writing Lab for extra help with comma usage.
The Writing Lab is located on the West Lafayette Campus in room 226 of Heavilon Hall. The lab is open 9:00am-6:00 pm. OWL, Online Writing Lab, is a reach resource of information. Its address is http://owl.english.purdue.edu. And finally, you can email your questions to OWL Mail at owlmail@owl.english.purdue.edu and our tutors will get back to you promptly.
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.
