Do you have any idea how hard it is to think up an enticing blog post title when your topic is sentence clauses? That’s about as unsexy a thing as can be discussed. My other options were Full Frontal Commas and When Punctuation Marks Hook Up, but I ultimately decided “sentences clauses” and “comma” both belonged because the union of those two language elements is what we’re talking about today.
I’m willing to bet that when writers express worry about their punctuation skills, their chief grief is commas. Like, when to use one and where to put it (by the way, if you block out the rest of this post, you have to admit what I just wrote could be sexy). Today I shall discuss one aspect of comma use: when they are required to separate sentence clauses and when they are not.
The guidelines are pretty simple. If you have a dependent clause, you don’t need a comma, and if you have an independent clause, you do need a comma. Important note: Dependent and independent clauses are typically separated by “and” or “but.”
But sometimes, to even the most experienced writer, grammar talk sounds like bleeeeeaaaaaaahhhhhhh grldlugnk fzzznuh. Therefore, I shall provide examples.
A sentence with a dependent clause:
Im-Ho-Tep was awakened from his ancient slumber and began killing the archeologists who disturbed his tomb.
Two things happened in that sentence. Im-Ho-Tep woke up, and he began killing archeologists. Each thing is described by a clause (as well as separated by “and”). I made the second clause dependent (without a comma) because the two things are connected. He was awakened and killed the people who woke him up, kind of like I wanted to kill the garbage truck that woke me up this morning at 5:45.
By technical definition, the second clause is dependent because it depends on the first half of the sentence for meaning. Began killing the archeologists who disturbed his tomb does not have enough information to be a sentence. It’s missing a subject.
Here’s one with an independent clause:
Im-Ho-Tep awoke from his ancient slumber, and he quickly decided to ditch the yellowed wrapping in favor of Versace and some nice bling.
I made the second half an independent clause because, while the subject (Im-Ho-Tep) does not change, the two actions aren’t directly related. By technical definition, the second clause is independent because it stands alone as a complete thought or idea. He quickly decided to ditch the yellowed wrapping in favor of Versace and some nice bling works as a sentence.
To recap: If your second clause depends on the first to make sense, you do not need a comma because the thoughts are not separate. If your second clause stands alone from your first clause as a functionally independent statement, you do need a comma. More examples follow…
Countess Dracula climbed out of her coffin and ventured into the night in search of human blood.
Two ideas are expressed and are separated by “and,” but ventured into the dark night in search of human blood is incomplete by itself.
Countess Dracula gazed longingly into the eyes of her human beverage container, and he gave it up to her after deciding there were far worse ways to die.
In this case, he gave it up to her after deciding there were far worse ways to die could be a sentence by itself, so you need a comma.
Dependent (with “but”):
Larry was bitten by a werewolf but did not transform into one until the night of the next full moon.
Did not transform into one until the night of the next full moon is not a complete sentence. No comma.
Independent (with “but”):
Larry became a drooling, uncontrollable savage last night, but that happens every weekend at his frat house.
That happens every weekend at his frat house is a complete sentence. Yes comma.
This is hardly a comprehensive explanation of when to use commas and when not to when composing a two-clause sentence, but I think the other scenarios are more intuitive.
Thoughts, comments, monetary donations are welcome below.