The comma has a great deal of uses with english grammatical rules. Not only are commas used for a pause, but they also help clarify and added fluidity to writing. However, one must be careful as the comma is often overused. Within grammatical structures, there are seven distinct comma rules, which to follow.
Rule 1 - Seperate Items in a Series
Within a sentence, when there are three or more items being listed in a series, they should be separated with commas. Although it has changed in the past, one should place a comma before the conjunction and last item in the series, within the sentence. See below for examples:
I brought a blanket, pillow, and sleeping bag to the sleepover.
My mom enjoys sports, knitting, and naps.
The game required a ball, bat, glove, and players.
Rule 2 - Seperate a Compound Sentence
A compound sentence is when two independent sentences are joined by a conjunction. When this is the case, a comma should be placed in front of the conjunction, before the second independant clause. A good test is to see if each side of the conjuntion is a complete sentence (i.e. it has both a subject and verb). See below for examples:
The game started in the morning, and the party began in the afternoon.
Test - The game started in the morning.
Test - The party began in the afternoon.
The teacher gave the test, but the children forgot to study.
Test - The teacher gave the test.
Test - The children forgot to study.
The prisoner was found guilty, so he was sent immediately to jail.
Test - The prisoner was found guilty.
Verb Phrase: was found
Test - He was sent immediately to jail.
Verb Phrase: was sent
Rule 3 - Seperate Introductory Elements
When a sentence has an introductory word, clause, or phrase which would be confusing without a pause, utilize a comma. See below for examples:
Each and every morning, I wake up and go straight to the shower.
To the New York Yankees, winning is a familiar theme.
Yesterday, I went to my son's football game.
Rule 4 - The Appositive Rule (Additional Information)
When a sentence offers additional information to add meaning or explanation, but is not necessarily required, set the non-essential clauses, phrases, and modifiers from the remainder of the sentence. A good test is to take out the additional information and see if the sentence still makes sense. If it does, you have an appositive. See below for examples:
The doorbell, which was installed yesterday, rang out loud.
Test - The doorbell rang out loud.
The holidays, although very expensive, are a wonderful time of year.
Test - The holidays are a wonderful time of year.
The criminal, who was denied parole, served the rest of his life in prison.
Test - The criminal served the rest of his life in prison.
Rule 5 - Separate Cooridinate Adjectives
When a group of adjectives come before a noun, separate them with a comma. This can be similar to the items in a series rule. The difference is that, in this case, the modifiers are adjectives. See below for examples:
The night had a dark, mysterious feeling.
The forecast was for a cold, dreary day.
Scientists could not predict when the powerful, explosive, and violent vocano would erupt.
Rule 6 - Separate Quoted Elements
When there is a complete quotation, utilize a comma to separate it from the remainder of the sentence. However, you do not need to use a comma to set off a partial quote (i.e. The president said that the war was "far from over.") See below for examples:
"Wait a minute," said Jenny.
"I didn't tell you to do that now," the boss interjected.
Steve indicated, "I love to go to the movies!"
Rule 7 - Seperate Two Clauses to Eliminate Confusion
If there are two distinct ideas, and it will help eliminate confusion, seperate the two ideas with a comma. See below for examples:
I don't mind Pepsi, but would prefer Dr. Pepper.
I chose option one and two, but really wanted the third choice.
The colors shown were blue and yellow, with a tint of green.