Spike That Comma: When to Mess with a Compound Predicate

Commas are such great fun. Using them properly, leaving them out entirely, or sticking them where they don’t belong—you can bring a lot of voice to your prose when you get crafty with commas, and not just in fiction or other forms of creative writing. In fact, subtle comma wizardry even has its place in formal registers like the ones we see in popular academia and its dustier, more straightlaced university-press counterpart. But those same spaces tend to traffic in a particular kind of overuse: non-standard commas in compound predicates.

These are the commas that come between a subject and the conjunction coordinating its second verb, and once you know how to recognize them, you’ll start seeing them everywhere, sometimes multiple times per page. Which is when the scowling starts.

In this post, we’re going to learn how to spot them, why they get so overused, and how to deploy them with crafty restraint.

Come. Let’s be geeks.

Compound Predicates Defined

First, we need to get a grip on some terms. English sentences are built of subjects and predicates. Basically, the subject is the thing that the sentence is about. It’s a noun or pronoun, and we usually see it up front. The predicate explains what the subject is doing and, in the case of linking verbs, what sort of state it’s in or quality it has. Here are a couple examples with the predicates underlined:

• The sparrow flew low and fast.

• Trade deficits climbed across sectors.

The predicate is basically a riff centred on the verb. Sometimes, it’s just the verb alone, and other times, it’s the verb and some backup singers. We get compound predicates when we get two of these riffs joined together by a conjunction.

• The sparrow flew low and fast and dove away from my living room window.

• Trade deficits climbed across sectors but were still misunderstood.

Drama, Emphasis, and Ambiguity

There’s a tight syntactic connection between subject and verb, and we don’t want just any old thing getting in the way, especially not little drips of punctuation that don’t introduce some kind of interjection. To show you what I mean, here’s a sentence with an adjectival interjection expanding on the subject and delaying our absorption of the predicates:

• Eric, mad with hunger, ripped the burger out of the woman’s hand and winced at the sound of her snapping fingers.

  
  

Normally, we’d expect to see “mad with hunger” as the sentence opener, but this kind of flippy-do is pretty nice sometimes. There’s some drama conjured by putting “mad with hunger” after the subject rather than slotting it as an introductory phrase. The pause further emphasizes the madness and even seems to extend it more causally to the ripping.

But imagine we saw this:

• Eric, ripped the burger out of the woman’s hand and winced at the sound of her snapping fingers.

Stunned, we’d read that as an errant comma, a bit of rogue punctuation cutting off the syntactic connection between the subject and its verb.

The same thing pretty much happens when writers put commas in compound predicates, like this:

• Trade deficits climbed across sectors, but were still misunderstood.

However, because there’s that first predicate and the conjunction, the interruption isn’t quite so jarring, and sometimes, it can be used to good effect. It works, for example, when you’re trying to get the cadence of a sentence to imitate its content. Like this:

• He looked at the photo, and started to cry.

• She picked up the gun, but set it back down.

In both examples, we can imagine the subject pausing before moving on to the second action, so the comma, while non-standard, is actually kind of cool.

We can also use this trick if we want to emphasize the second predicate, which is how writers working in more formal registers should think about this technique.

• Trade deficits were explained for hours, but were still misunderstood.

Finally, there’s the odd time when a comma is actually necessary to avoid ambiguity. According to The Chicago Manual of Style, commas in compound predicates are discouraged except in this particular case, and the following example is provided:

• She recognized the man who entered the room, and gasped.

Without the comma, “and gasped” sinks into the relative clause (“who entered the room”), so we need something to make the conjunction coordinate “gasped” with “recognized,” not “entered.” Hence our comma.

Reining It In

In each of the above examples, the comma is a considered addition, and we can imagine we’d only sometimes undertake all that consideration. Our writing just wouldn’t work as well if we started doing it for every sentence or even most of them. The effect would be lost. And yet, rampant overuse persists, particularly in certain strands of non-fiction.

It could be that writers are seeing conjunctions like “and” or “but” and automatically inserting commas because they think they’re dealing with a compound sentence. That’s understandable enough. The structures are similar, but whereas a compound predicate has two verbs and one subject, a compound sentence has two verbs and two subjects, each pair in its own independent clause. Here’s one now:

• They explained trade deficits for hours, but the president still didn’t understand.

Sure, we have two verbs here (“explained” and “understand”), but we also have two subjects (“they” and “the president”). The second subject creates a whole new clause, so standard usage calls for a comma and a conjunction to divvy things up.

If you want to make sure you’re not overdoing it, I have a hack you can use to spike a few commas. Hover your magnifying glass over the conjunction between the verbs, scanning back and forth for a second subject kicking around before the second verb. If you don’t see that second subject, you probably don’t need the comma.

The first few times you do this, you might get thrown off by an object of the first verb, so just make sure the noun you find has a connection to the second verb, not the first, which makes a lot more sense when you see an example:

• They bought chips and gum, and they ate together on a park bench.

That’s the compound sentence, the first clause containing a predicate with two objects and the second a new subject.

Here it is with one clause, one subject, and two predicates:

• They bought chips and gum and ate together on a park bench.

Distinguishing between objects and subjects isn’t so hard when you see them this way, and the more you do this, the easier it gets.

If you’re using a lot of commas in your compound predicates, your writing will almost certainly benefit from cutting many of them back—maybe even most. In some cases, you might need one to avoid ambiguity, but in most, they’re a tool for emphasis or drama, both of which work best when we deliberate over our usages, and practice a little restraint.