The Grammar Doctor

Comma Rules

What do commas really mean? We think of spoken language as a series of sounds, but an important part of language is the pause between sounds. We pause briefly between words so that our words don't run together. We make a longer pause at the end of a sentence to signal to our listeners that we are at the end of a thought.

We also pause within sentences to signal a change of the flow of thought within that sentence. Here are three structures that change the flow of thought within a sentence.

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.

Click here for a comma quiz

Do you still have questions?

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