1. Purdue University Writing Lab
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.
Purdue University Writing Lab

2. 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.
Key Concept: Commas should be placed between each element within a list. This placement can help the reader to avoid confusion.

3. Sentence Structure: Commas in a Series
Consider the difference in the following:
Last month, Alex played with Mary Ann Lee and Kim.
Last month, Alex played with Mary, Ann, Lee, and Kim.
Last month, Alex played with 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 girls did Alex play with?

4. 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.

5. 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

6. Commas in Quotations Follow your rules for dialogue punctuation.
If the He said comes first, place the comma after said.
He said, “I know Kung Fu.”
If the he said comes after the quote, place the comma inside the quotation marks after the last word in the quotation.
“I’ll dance with you,” he said.

7. Commas in Quotations
If the he said comes in the middle of the quote, place the comma inside the quotation marks after the last word in the first part of the quote and after the he said.
“Put the box,” he said, “in the house.”
Purdue University Writing Lab

8. A Common Comma Error: The Comma Splice
A comma splice is an error in which two sentences are joined by a comma.
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.

9. To Correct a Comma Splice
Insert a conjunction between the two sentences.
Start a new sentence.
Insert a semi-colon between the two sentences.
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.