Commas with and

Q:

This question has to do with punctuation. When should we use a comma before and?

Vera
vcqm@ruralsp.com.br

A:

Here are some comma rules. Rules 3–5 are mainly from pages 325–326 of Keys for Writers by Ann Raimes (Houghton Mifflin, 1996). I have added a few examples and some parenthetical remarks.

1)

Use a comma before and to join two independent clauses: Joe's mother was a famous neurosurgeon, and his father was a celebrated actor. We'll be celebrating the new year together, and we'll probably be celebrating the arrival of our new baby, too.

2)

Use commas to separate three or more items in a series: In the car, detectives found nothing more than a beach towel, suntan lotion, and a large straw hat. He spoke forcefully, with references to the nation's history, its successes, its failures, and its destiny.

3)

Use commas to separate coordinate adjectives: Coordinate adjectives can be identified by the fact that their order can be reversed and the word and can be inserted between them. They do not give information about size, shape, age, color, nationality, religion, or material. Separate coordinate adjectives with commas: He hired people who are energetic, efficient, and polite. The new medicine worked wonders, but it made Helen nervous, shaky, and irritable.

4)

Do not put a comma between a final adjective and the noun it modifies (or after and just before the final adjective): Energetic, efficient, and polite salespeople are much in demand.

5)

Do not use a comma before part of a compound structure that is not an independent clause (that is, does not contain both its own subject and verb): Amy Tan has written novels and adapted them for the screen. Tan has written about her mother and the rest of her family.

I hope this is clear, and I hope it helps.