The Oxford Comma, Also known as the Serial Comma ---You Should Use It!
I like cooking, parents, and my dogs.
The child played, sang, and slept in the afternoon.
Who will volunteer to wash the dishes, sweep the floor, or make the beds?
Use a comma to separate three or more items that are listed in a sentence. See the examples above. Notice that there is a comma in front of the conjunctions ( "and" and "or").
These is a debate among grammar nerds about whether or not that last comma (the Oxford comma) is necessary. And this grammar debate has seeped into popular culture. For instance, the indie pop group, Vampire Weekend, has a song called "Oxford Comma," and it opens with the line, "Who gives a f**k about an Oxford Comma?" We don't really have to join the debate, but we should use the 'ole Oxford Comma for the TSI.