To Comma or Not to Comma
"I was working on the proof of one of my poems all the morning, and took out a comma. In the afternoon I put it back again." -- Oscar Wilde
Commas have 5 Primary Uses:
1. To separate items in a list
Remember, the comma before the conjunction is called the "Oxford" comma. Its usage is considered "optional," but you should be consistent with either using it or not using it. As it can actually affect the meaning of your sentence whether that comma is there or not, make sure that your meaning is absolutely and unmistakably clear!
2. To set off introductory material
Remember, this comma is needed only when the introductory material is at the beginning. If the order of words is reversed, the comma becomes unnecessary: Sarah auditioned for a role in her school play last Friday.
3. To set off interrupting words:
If a sentence is interrupted by non-essential information, a word or phrase that adds detail, but is not grammatically necessary for the sentence to be understood, that non-essential information needs to be set off with commas.
Without the interrupting phrase, the sentence still makes sense: Her song choice showed off her vocal range perfectly.
Remember, commas should be used on both sides of the interrupting phrase.
4. To separate independent clauses when used with a conjunction:
When joining two complete sentences with one of the FANBOYS conjunctions (for, and, nor, but, or, yet, so), a comma is needed before the conjunction For example:
5. To set off a direct quotation:
Direct Address: Sarah, there will be other plays.
Salutations and closings of friendly letters: Dear Sarah,
Numbers over 999: 1,000; 5,265
Between town and state/country: Wilmore, Kentucky; Frankfurt, Germany; St. Andrews, Scotland