Punctuation

Punctuation rules The Comma

I. Introductory expressions
Anything that goes before the subject is introductory. Introductory expressions are followed by a comma if - they are five or more words long, or - they have a verb form EXAMPLES Everything was fine Before those people moved next door, everything was fine. In the first year of the marriage, everything was fine. In the beginning everything was fine.

II. Interrupters
Use commas to separate any expression that interrupts the flow of thought in a sentence. EXAMPLES My cousin figured it out. My cousin, who is not a rocket scientist, figured it out. My cousin, by the way, figured it out. My cousin, nevertheless, figured it out. Do not use commas to separate an expression that does not interrupt the flow of thought. The man who first discovered gold in California died in poverty. Sam Jackson, who first discovered gold in California, died in poverty.

III. Compound Sentence
Use a comma along with a conjunction to separate the two clauses of a compound sentence. EXAMPLE Bill is going to save his money, and then he is going to buy a new car. A sentence is not compound if it does not contain two independent clauses. EXAMPLE Bill is going to save his money and then is going to buy a new car.