CRT Grammar Review

Commas

Commas are one of the most widely used punctuation marks in the English language. They are used in several places for different reasons.

1. Use a comma before the eight coordinating conjunctions (and, or, so, but, nor, yet, for, although). Examples:
  • He came early, but she came late.
  • I was ready to leave, but he didn't see my ride.
  • I was hungry, and I wanted to eat.
  • It was raining, so I walked him to the bus.

2. After a subordinate clause that comes before a main clause. Subordinate clause: has a subject and a verb, but is not a complete sentence. Subordinate clauses are often used to add information to another clause, especially to tell about specific circumstances. Examples:
  • When I'm hungry, I go to my favorite restaurant.
  • Despite the fact we were tired, we stayed up to watch a movie.

3. Around extra information that does not include a verb. Examples:
  • New Hampshire, a state with many tall mountains, is my home.
  • My son, Rick, is home from college.
  • My father, a good doctor, took care of me when I broke my arm.

4. With non-defining relative clauses. Similar to #3, non-defining relative clauses give additional information about something, but does not define it. Examples:
  • Professor Smith, who teaches the evening class, is at home.
  • Central Park, which was built by Olmsted, is one of the world's most venerated parks.

5. Between two elements or items in a list. Examples:
  • I like bananas, pears and peaches.
  • I took a several classes my first semester in college: English 1010, Theatre 1020, Biology 1010 and Math 1050.

Sources http://www.scribd.com/doc/14819641/Rules-for-Using-COMMAS