Let’s jump right into the topic of commas. Here I’ll describe the five main uses of commas.  We’ll talk about how to use comas, when and when not to use comas, and give you examples.

Between Items in a Series

Commas are used to separate three or more items in a series. (Don’t use a comma when the series contains only two words.) Items in a series may be single words, phrases, or clauses.  

Example: Placing Commas Between Items in a Series

Beautiful redwoods, ferns, and hiking trails are all found on the California coastline.  

My father willed me all of his property, houses, and warehouses. 

My mother baked cookies, planned the Christmas party, and bought gifts for everyone.  

Practice 1

Place commas between items in a series. 

1. My family likes to recycle newspapers aluminum and plastic.

2. Jogging backpacking and horseback riding are my favorite pastimes.

3. Mom gathered the kids loaded the minivan and set off for the zoo.

4. Signs of burnout include insomnia inability to concentrate and depression. 

After Introductory Material

A comma is used to separate introductory material from the rest of the sentence. The most common introductory word groups are clauses and phrases functioning as adverbs. These kind of words groups tell the reader when, where, how, why, or under what conditions the main action of the sentence occurred. 

Practice 2

Place commas after the introductory material of each sentence below. 

1. During our Valentine’s Day dinner last year my boyfriend finally proposed to me.

2. When the shock wore off from him proposing I told him I would marry him.

3. Pausing in the doorway the blushing bride smiled as she entered the reception room.

4. After a long night of dancing and drinking the bride and groom were exhausted. 

Around Words that Interrupt the Flow of a Sentence

Sentences sometimes contain material that interrupts the flow of though. Such words and word groups should be set off from the rest of the sentence by commas. The material added to the sentence that interrupts the flow of thought is often less important to the sentence. 

Examples:

My brother, who is neat, complains that I am too messy. 

The house we’re buying, which was built in 1950, needs a new roof and new windows. 

Practice 3

Place commas around the interrupting words in each of the following sentences.

1. The downstairs neighbor, grumbling angrily, came upstairs to complain about the noise.

2. The new skyscraper seventy stories high offers a beautiful view of the entire city.

3. Some employees on the other hand would rather not be distracted by such a beautiful view. 

Between Complete Thoughts Connected by a Joining Word

When two complete thoughts are combined into one sentence by a joining word like and, but, or so, a comma is used before the joining word. 

Example:

They were five strangers stuck in an elevator, so they told each other jokes to ease the tension. 

Each part of this sentence is a complete thought, combined into one sentence by the joining word so. Only use a comma in this way when the joining word comes between two complete thoughts. Each of those thoughts must have its own subject and verb. 

Example:

Comma- My best friend spends two hours at the gym every night, and then she goes to class.

No Comma- My best friend spends two at the gym and then goes to class. 

Practice 4

Place a comma before the joining words in the following sentence.

1. My mother wanted to attend college but her family couldn’t afford the tuition.

2. My best friend has a internship this summer and my boyfriend has hired for the same position as her internship.

3. Someone had broken into the house but nothing had been taken.

4. I forgot my reading glasses at home so I had trouble reading the test at school. 

With Direct Quotations

A comma is used to separate directly quoted material from the rest of the sentence. When the comma is placed at the end of a quotation, it is included within the quotation marks. 

Examples:

Someone screamed, “Help! Please help me!” 

Practice 5

Place commas to set apart quoted material in the following sentences.

1. Susan whispered “Only fifteen more minutes until this class ends.”

2. “Never reach your hands into the cages” the zookeeper told the visiting children “because the animals might bite your hands.”

3. “Please leave your name and number after the beep” said the voice on the answering machine.