How Use Commas
Commas
exist to help readers make sense of writing. Commas serve, primarily, to break
ideas into clear packets. Put another way, they keep words and ideas from
running together in a confusing manner.
Conjunction Commas
Use a comma before a conjunction that joins two independent clauses. The comma warns the reader that one independent clause is done and another is coming. (and, but, or, nor, for, so, and yet)
Example: I have always wanted to be an English teacher, but I fell into history instead.
Exceptions: If the independent clauses are short and the reader couldn't possibly be confused, the comma may be omitted.
Exception Example: My mother is dead and I am sad.
Introductory Clause Commas
Use a comma after an introductory clause or phrase. Little tacked-on words or phrases that say when, where, why, how, and under what condition the issue discussed in the sentence occurred need to be set off with a comma. This warns the reader that the main part of the sentence is about to start.
Example (adverb type): When I first started teaching, I had nightmares about grammar.
Example (participial type): Completely confused, the dog walked into the guard tower.
Exceptions: You may leave the comma out after a short adverb clause if there is no chance of confusing the reader. Note, if the introductory clause modifies the subject, the comma is required.
Exception Example: Immediately the rain started.
Exception Counter-example: Green with envy, John watched Carlos.
Adjective Phrase Commas
Use a comma after phrases that function as adjectives.
Example: My head, given its huge size, often causes me severe pain.
Appositive Commas
Use a comma to set off appositives (noun or noun-phrase that renames another noun in the same sentence).
Example: Stephen King's novel, Cujo, is kind of dumb.
Exception: If the noun or noun phrase doesn't actually re-name, but rather clarifies, no comma is required.
Exception Example: The song "Diamonds are a Girl's Best Friend" is annoying.
Adjective Clause Commas
Use a comma to set off adjective clauses. These are sentence nuggets that sit inside a sentence and modify another noun in the sentence. They come right after the noun they modify. Only use this comma with clauses which could be left out with losing the sentence.
Example: My car, which I hate with all my heart and soul, costs me at least a grand a year in repairs.
Series Commas
Use a comma between all items in a series.
Example: There are three things that can make me skip dinner: a good movie, a good book, and a conversation about commas.
Adjective Separator Commas
Use a comma to separate two adjectives that each modify a noun separately. If the adjectives modify each other, don't use comma.
Example: The best thing about kids is that they are curious, humorous people.
Counter-Example: I have always hated loud pop music.
Parenthetical Phrase Commas
Use commas to set off parenthetical phrases. Parenthetical expressions are phrases that provide some extra information and are not required by the sentence.
Example: I am about 6 feet tall, give or take a few inches.
Example: Chicken, that freaky meat, tastes like everything that is not an official meat.
Transitional Expression Commas
Use commas to set off transitional (or contrasting) expressions. (however, therefore, for example, in other words, not, never, unlike, etc. are the expressions.)
Example: I dislike you; therefore, you must slink away.
Example: Cats are smarter than dogs. Dogs, however, are bigger.
Example: Football players, unlike normal humans, deliberately put themselves in massive physical danger.
Absolute Phrase Commas
Use a comma to set off an absolute phrase. These are phrases which have something to say about the entire sentence. They usually appear at the beginning or end of a sentence.
Example: The last teacher unconscious, Lawrence Lovato ruled the school.
Example: I was forced to resort to a pure lettuce diet, my stomach having been upset by the huge amount of rattlesnake I had eaten.
Quote Commas
Use commas to set quotes off from the rest of a sentence.
Example: And then she said, "I've never seen anything quite like it.