Tip #8 - Comma Rules, Part One

Unless they come at the beginning of a sentence, after an introductory phrase or clause, or precede a concluding phrase or clause, commas usually come in pairs. In the previous sentence, for example, they surround the phrase “after an introductory phrase or clause,” which explains “at the beginning of a sentence.” In both preceding sentences a comma also is used between clauses. So here are a couple of rules:

#1 - One comma separates independent and dependent clauses in the same sentence. Examples:

John took a taxi, as it was too far to walk comfortably to the museum.

INDEPENDENT CLAUSE - COMMA - DEPENDENT CLAUSE.

If rain is forecast, please take your umbrella.

DEPENDENT CLAUSE - COMMA - INDEPENDENT CLAUSE.

#2 - Use commas in pairs to set off nonessential phrases, clauses, appositives, interjections, direct address, and so on as needed, except when they begin or end the sentence. Examples:

John, would you set the clock for me?

DIRECT ADDRESS - COMMA - INDEPENDENT CLAUSE.

She knew, for example, how to tie her shoelaces.

“FOR EXAMPLE” INTERRUPTS AND IS SET OFF WITH COMMAS.

Are there exceptions? Of course. After all, this is English, and what would our language be without exceptions to every rule? For instance, most modern writing avoids the comma following a short introductory prepositional phrase: “In January we will go skiing” rather than “In January, we will go skiing.” The latter form would have been more common, if not indeed required, fifty years ago. If the introductory phrase is long or might confuse the reader, however, the comma should be used.

Note in Rule #2 above the word nonessential. Essential clauses are not set off with commas. For example: “The woman who is wearing a red hat is my aunt.” Without the clause “who is wearing a red hat” the reader wouldn’t know which woman is the writer’s aunt.

More about commas in future posts.