Commas are an important punctuation and are used in a variety of situations.  Here is a list of the situations:

1. Before conjunctions when there’s a following subject:

James is tall, but he doesn’t like to play basketball.
Marie forgot her math textbook, and she has a test today.

BUT: if there’s no subject following, then there’s no comma.
I like to cook but don’t like to clean up afterwards.

2. In a list of 3 or more nouns or verbs:

She bought a skirt, stockings, earrings and a coat.
He got gas, put air in the tires, and changed the oil in the car.

[Note:  the comma before and is optional.]

BUT: if the list only has 2 things, there is no comma:
We need to replace the stove and refrigerator in the kitchen.
John and George like to snowboard and hike together.

3. After introductory words before a main clause: 

Unfortunately, there were many mistakes made.
Furthermore, we have to paint the entire exterior of the house.

4. To separate 2 or more adjectives of equal value: [adjectives that are equal can be reversed or connected with “and”]

He’s a tall, handsome young lad. [handsome and tall can be reversed, but handsome and young cannot]
That man is a sloppy, dirty, ill-mannered person. [all 3 can be reversed]

5. Before question tags:

She’s coming with us, isn’t she?
We can’t use our dictionaries, can we?

6. After introductory dependent clauses:

Because he was repeatedly late, the teacher asked him to withdraw from class.
As I was coming to school, I saw an old friend on the bus.

BUT: When the dependent clause comes after the independent clause, there’s no comma.
He stayed home from school because he was sick.

7. In dates, addresses, and city-countries:

He was born on Sunday, June 25, 1989.
They live on West 22^nd Street, Vancouver, B.C.
They visited their friends in London, England.

BUT: When there’s only a month and year, no comma is used
They got married in June 2005.

8. After long introductory prepositional phrases: [longer than 5 words]

On the morning of her first day of school, Sandra woke up early.
During the snowstorm in January of last year, there were many car accidents.

9. Around extra information adjective clauses:

My last teacher, whom I liked very much, taught us about popular psychology.
Vancouver, which lies on the west coast of Canada, is a major port city.

BUT:  When the adjective clause has necessary information, there’s no comma.
Would all the students who need bus passes please follow me.

10. Around interrupters (including names): [interrupters are words that are added but aren’t necessary]

Margaret Thatcher was, as they say, a formidable woman.
The decor was excellent.  The food, on the other hand, was poor.
Michael, what do you think of our new kitchen?

11. Around (or after) appositives:

Bermuda, a popular honeymoon destination, is a two-hour plane trip from New York City.
A brilliant young boy, Andrew was admitted into the special school.

BUT:  if the appositive is only a name, no comma is used.
My friend Alice is coming with us.
Her brother Gary will be in charge.

12. Before “which” when the following adjective clause modifies more than just the last word:

The clown slipped on a banana peel, which made all the children laugh.
Jessica left the club and went home early, which is unusual for her.

13. With quotes:

Jonathan said, “I’m seeing a girl in the neighboring town.”
“I was able,” she told me, “to complete all my work.”

14. Before end-of-sentence words that add information:

 She wants to go to the movies, too.
His father is chief of police, you know.

 
© 2014 Ambien Malecot