Introduction to Commas: Coordinating Conjunctions

What is a Comma?

In the simplest terms, a comma is a punctuation used to indicate a break in a sentence or list. In school, you may have been taught that whenever you would pause in a sentence a comma should take its place, or you may have been taught always to put one before a FANBOY. While these rules worked great in school, for professional writing, there are more strict and clear rules to follow when using a comma. 

Commas and Coordinating Conjunctions

Sometimes better known as FANBOYS, coordinating conjunctions are words that connect other words, clauses, and sentences. The nickname FANBOYS comes from the seven coordinating conjunctions that are used: For, and, nor, but, or, yet, and so. When you want to connect two or more independent clauses, sentences that can stand on their own, you can use a comma and a FANBOY to do so; such as: "I wrote this blog for you, and I hope it helps." In that example, there are two sentences that can stand on their own: “I wrote this blog for you” and “I hope it helps.” Instead of having two choppy and short sentences, I connected them with a coordinating conjunction after a comma. 

The best way to check if you need a comma for a FANBOY is by reading the clauses before it and after aloud; if they work alone and you can identify clear subjects and verbs in both, they need a comma. If you read both parts and it sounds awkward, a comma would be unnecessary. The most frequent mistake like this is when using and connecting two dependent clauses or words. If you are running to the store but then home, a comma wouldn’t make sense before “but” because “then home” cannot stand on its own. This is also true when making a list of only two items; if you made dinner and drinks, a comma before “and” would mean the phrase  “drinks” could be its own sentence, which it can’t be. Another common mistake is thinking you can use just the comma and not a coordinating conjunction, but a comma on its own without a coordinating conjunction connecting two independent clauses is a comma splice.

Tricky Situations

As with most rules in the English language, it’s hard to create a rule to fit every single instance of a comma and coordinating conjunction. One such troublemaker is “nor.” Using nor is a bit harder than others because a comma sounds natural almost every time, but it isn’t grammatically correct. When using nor, a comma is only needed if the second part has a clearly stated subject; however, this tip would work on any of the other six coordinating conjunctions too. For instance, I can neither tell you a one-fits-all rule for commas nor make one. In that sentence, there isn’t a clear subject in “make one,” so a comma isn’t needed. If I wanted, I could easily write it to include one by saying: I cannot tell you a one-fits-all rule for commas, nor can I make one. That time, both “I cannot tell you a one-fits-all rule for commas” and “can I make one” have clear subjects.

The other error we see many authors running into is imperatives and the use of coordinating conjunctions. An imperative clause is something like “go clean up” where there isn’t a clearly stated subject, but the subject can be assumed and is considered an independent clause. Since there isn’t a clear subject in “go clean up,” it’s easy to assume you could just add another imperative without the need for a comma. However, despite the lack of a clear subject being written, a comma is still expected since they are independent clauses, so you would write “go clean up, and put the phone away” not “go clean up and put the phone away.” The exception to this is never splitting compound predicates, when two or more verbs share a subject, with a comma. If you are telling someone "you can go to the store and get some apples” a comma is not needed because the instructions, go to the store and get apples, are for the same subject.

Final Thoughts

The rules for using a comma, when, and why are tough to master; even the best writers will add a comma they thought was needed just to catch it wasn’t, but the difference is being able to understand why and catching it before others are given your work. This is by no means a comprehensive blog, and more is to come on comma mastery, but take what you’ve learned here, and improve your writing!