Do you know where to place commas in a sentence?
A lot of writers say they’re guided by instinct when it comes to commas. Or they use the “rule” that says a comma goes where we naturally pause.
But what if your “instincts” are a bit off the mark? Or what if a reader doesn’t pause where you pause?
A big mistake that many writers make is called a split compound predicate.
What is it? Let me explain by backtracking a bit first.
A complete sentence is also called an independent clause. It consists of a subject—the actor—and a verb—the action or state of being that goes with it. It’s called independent because it’s complete, and it can stand alone.
The subject of a sentence, in the broad sense, also includes the words and phrases that describe (or modify) the actor. The verb (the subject’s action or state of being) is called a predicate, and the term can be used to describe all parts of the sentence that modify the meaning of that verb.
For our discussion here, though, we’ll just stick to the subject and predicate in the basic sense: the actor and the action. Let’s take a look.
Billy runs in the street.
In this sentence, Billy is the subject, and runs is the predicate (the verb). The subject is called a simple subject because there is only one subject: Billy. (If there were two or more it would be called a compound subject.) And the predicate is called a simple predicate because there is only one verb: runs.
Now let’s add another verb that goes with the subject.
Billy runs and sings in the street.
Billy is still the subject, but now he’s doing two things: runs and sings.
Two separate verbs used to show two actions that the subject makes is called a compound predicate.
Here are a few more examples.
My friend bikes and skates.
Jacinda writes and plays guitar.
Jamie paints and draws.
Alfonso cried and laughed.
There’s no need for commas because these sentences have just one independent clause even though they have compound predicates.
Here are the same sentences with the compound predicates mistakenly split up by commas. Read out loud and pause at each comma.
My friend bikes, and skates.
Jacinda writes, and plays guitar.
Jamie paints, and draws.
Alfonso cried, and laughed.
Which set sounds more natural? The sentences with or without the commas?
If there’s any pause at all in the first set (without commas), it’s likely to be a tiny pause after the subject as your eyes scan ahead to prepare for what’s next. You might drag out my friend or Jacinda, for example, just a little bit as you scan, and then bikes and skates or writes and plays guitar will be said quickly, almost as one word or in a steady beat. Your results may vary if you’re not a native speaker of English.
Myyy friendddd bikesandskates.
But the pause is so short there’s no reason to use a comma (and no rule exists that says you should).
In the second set of sentences with the commas, the pause at the comma breaks up actions that go together as a group.
Jacindawrites—and plays guitar.
Why group the subject with the first verb by placing a comma after it? There’s no sense to it unless you have some special situation where you want the reader to pause for emphasis. In that case, you’d probably want to use an em dash (like this —) if anything.
These sentences are very simple: each has one subject and two verbs called a compound predicate. There is no need to separate the ideas.
Splitting a compound predicate with a comma is the worst punctuation mistake ever.
I’d much rather lament a missing Oxford comma (apples, oranges, and pears) because I know the reasoning behind it even if I don’t agree. Plus, the AP Stylebook endorses it though other style manuals don’t.
But breaking up a compound predicate with a comma makes no sense. It makes the reader stumble and wonder who is doing what. And there’s just no reason or rule for it.
Let’s take another look at the same sentences jazzed up a bit.
My best friend bikes when she has the time and skates on weekends when the weather is nice.
Lucy’s neighbor Jacinda writes for a living and plays guitar at coffeehouses once in awhile.
Jacinda’s boyfriend Jamie paints gorgeous portraits for a downtown gallery and draws landscapes in his spare time.
Lucia’s son Alfonso cried when the dog took the ball away and laughed when he brought it back.
These are essentially the same sentences with a bunch of modifiers added. Do any of them need a comma? If so, where would you put one? Why?
Each sentence has the same subject and compound predicate at its core even though additional descriptive words and phrases have been added.
But those sentences are pretty long and quite a mouthful, you might think. Shouldn’t you use a comma just to break things up?
Excellent point. But you shouldn’t use a comma just to break things up.
If you’re going to use a comma, you should know why you’re using it.
Here’s one of those sentences with even more padding:
Jacinda’s handsome boyfriend Jamie paints gorgeous portraits in oil that he sells at a downtown gallery and draws stunning landscapes with pencil and charcoal in his spare time.
Now we’ve really got a complicated sentence. It’s still just an independent clause with one subject and the same compound predicate, but by the time you get to the second verb draws, it seems like it’s just hanging there by itself. Who draws? The gallery?
Let’s add a comma.
Jacinda’s handsome boyfriend Jamie paints gorgeous portraits in oil that he sells at a downtown gallery, and draws stunning landscapes with pencil and charcoal in his spare time.
Draws is still hanging there all by itself even with the comma. And what we’ve got is not only a split compound predicate, we’ve also got a sentence fragment that’s dependent and can’t stand alone. That applies to the shorter examples as well.
An overly lengthy sentence with a simple subject and a compound predicate doesn’t need a comma; it needs to be reworked.
Here’s what I would do.
Jacinda’s boyfriend Jamie paints gorgeous portraits in oil that he sells at a downtown gallery, and he also draws stunning landscapes with pencil and charcoal in his spare time.
I added another subject (the pronoun he refers back to Jamie) to make the second part of the sentence an independent clause. That way, when readers pause at the comma, they get a refresher on who, exactly, I’m talking about. Plus, the transitional word “also” gives the reader a sense of continuation.
The rule for commas and independent clauses might help.
It goes like this:
When two independent clauses are joined by a coordinating conjunction such as and, or, nor, for, so, yet, or but, place a comma at the end of the first independent clause before the coordinating conjunction.
This also gives insight on why you shouldn’t split a compound predicate: the result creates a dependent clause no matter how many descriptive words are used to describe the action. And a dependent clause or a phrase—in this case a group of words with a verb and no subject—shouldn’t be separated from its parent clause (the independent clause with the subject) by a comma.
Here’s another way to restructure that long sentence.
Jacinda’s boyfriend Jamie paints gorgeous portraits in oil that he sells at a downtown gallery. He also draws stunning landscapes with pencil and charcoal in his spare time.
Just break it into two sentences. And don’t let that he sells at a downtown gallery throw you off. It might look like an independent clause, but it’s not (it’s a relative clause that’s dependent on the main clause).
Either way, the sentence is now easier to read, and you haven’t split a compound predicate.
I’m all for breaking the rules when breaking them creates a nice effect, but be sure you know the rules before you break them. Otherwise your writing will suffer, and may the grammar gods help you if you end up with a sentence like this:
I’m spending the day at home, and am working on my next project.
It’s the “and am” that drives me up the wall. I see versions of this far too often. Is it a trend or something?
Whether you like following rules or not, be kind to your readers and don’t split your compound predicates.
What about you? Have you made this mistake? Have you seen it? What punctuation mistakes make you buggy? Share in the comments!