Commas the Chicago Way: Can We Depend on Commas in Dependent Clauses?

 In Grammar

Like most things to do with commas, kinda.

Do you want to read this series in order? Start here.

As we learned in our previous entry, knowing what to do with commas means knowing the meaning of all those grammar terms that leaked out of our heads over summer vacation. So we will hit up that part first, and then dazzle you with comma rules.

Remember that sometimes grammar terms have multiple names. If that is the case, I’ve included them in parentheses.


The subject is the thing in our sentence the spotlight would be on if our sentence were a play.


Branagh directed.

Would the spotlight be on directed? Kenneth Branagh would be the first person to tell you the spotlight should be on him. He is the subject of this sentence, so in this case grammar and Branagh agree that the spotlight should be on him.


Predicate is a fancy word that means: the words in the sentence that aren’t the subject that tell us more about the subject. Predicates have verbs in them.


Branagh directed the film Murder on the Orient Express.

We know that Branagh is the subject. The rest of the sentence is giving us the information that the subject directed the film Murder on the Orient Express. Those eight words are the predicate.


Here’s what Merriam-Webster has to say about clauses: “a group of words containing a subject and predicate and functioning as a member of a complex…or compound..sentence”

We’re going to set aside complex and compound for now and sum this up as: clauses are bits of sentences that have subjects and predicates. There can be more than one clause in a sentence, so get ready for that.

Independent clause (main clause)

This was the focus of the last comma series article. Chicago defines independent clauses in 5.225, and my favorite grammar website Grammar Bytes says that an independent clause “must contain a subject and a verb as well as express a complete thought.”


Branagh’s Hercule Poirot sported an impressive mustache.

  • Subject: Branagh’s
  • Verb: sported
  • Complete thought? Yes!

Dependent clause (subordinate clause)

This is our focus in this article, so let’s make sure we really track this. In 5.225, Chicago reminds us what a clause has (subject, predicate) tells us about independent clauses, (they’re the previous term we defined, see above) and then says, “a dependent clause cannot stand alone because of the presence of a word by which it would normally be linked to an independent clause.”

Linkage is key for dependent clauses. It needs to be linked to another clause because it cannot stand alone. And not being able to stand alone means it doesn’t form a complete thought.

It’s kind of like talking on the phone to a person who is distracted by something else. You don’t get all the information you need.


Once the train crashed

As you can see with that example, we need more information to finish the sentence. When you feel like prompting someone to finish their sentence, chances are you have a dependent clause.

Coordinating conjunction

Whew, let’s take a break from the above and talk coordinating conjunctions, which are one of my favorite grammar things because (1) there are seven of them, and (2) they are easy to remember because you can arrange them into the acronym FANBOYS

  • F = for
  • A = and
  • N = nor
  • B = but
  • O = or
  • Y = yet
  • S = so

Coordinating conjunctions join things together and the things they join are equal. Think of the Conjunction Junction train. Those coordinating conjunctions hooked up train cars.

Subordinating conjunction (subordinate conjunction)

This is another grammar term that paints a picture. If you know that the word subordinate means “placed in or occupying a lower class, rank, or position” as Merriam-Webster defines it, then you can guess that a subordinating conjunction is hooking up two things that are not of the same class, rank, or position.

So one job of the subordinating conjunction is to let us know that the clause it is part of is not the important one.


Though Branagh used a lot of swooping camera angles, they did not distract from the excellent plot and characterization of Agatha Christie’s novel.

  • Less important: Branagh’s swooping about with the cameras. In this case, though is the subordinate conjunction.
  • More important: Agatha Christie knew how to write a mystery.

The other job is to provide the transition between sentences. As Grammar Bytes tells us, “This transition will indicate a time, place, or cause and effect relationship.”

Grammar Bytes also has a nice list of subordinating conjunctions which comes in handy if you are making up example sentences. (As one does.)

Restrictive clause (defining clause)

See, I would call these essential clauses. Bad naming, grammar folks. The other name, defining clause is a little more descriptive.

Merriam-Webster says that restrictive clauses are: “a descriptive clause that is essential to the definiteness of the word it modifies.”


The vacation that Hercule Poirot planned did not come to pass.

Restrictive clause: that Hercule Poirot planned
Why? Without that clause we’d just be left with a vacation not coming to pass and be missing the important information of who (Poirot) and what (planned).

Good news! Restrictive clauses usually start with that/who/whom/whose.

Nonrestrictive clause (supplementary clause, parenthetical clause)

If you’ve wrapped your head around the restrictive clause, then this one is easy to remember if you keep it mind it’s the opposite.

In the last example we needed to know that it was Hercule Poirot who planned in order to understand the rest of the stuff about the vacation that didn’t come to pass.

Nonrestrictive clauses are the extra things in the sentence which we can remove and the sentence will still make sense.


Kenneth Branagh’s Murder on the Orient Express, his first movie since 2015’s Cinderella, grossed $352.8 million worldwide.

In this case, we could take out the nonrestrictive clause (his first movie since 2015’s Cinderella) and still have a sentence that makes sense:

Kenneth Branagh’s Murder on the Orient Express grossed $352.8 million worldwide.

We made it through the grammar terms! On to the rules!

Sand on the beach. Text: 6.24 Commas with introductory dependent clauses

If your sentence starts with a dependent clause, Chicago wants a comma after that dependent clause. Remember that dependent clauses often start with a subordinating conjunction.


After Kenneth Branagh finished Murder on the Orient Express, he tackled another literary figure in All is True.

Remember that if we just had the first part of the sentence (After Kenneth Branagh finished Murder on the Orient Express) we would still need more information to make sense of the sentence. That’s how we know it’s a dependent clause.

I like to think of the comma here as a sort of arm flourish saying that there’s more coming in the sentence.

Sand on the beach. Text: 6.25 Commas with dependent clauses following the main clause

Okay, here we’ve got a yes & no situation and our goal is to cement in our mind which is which.

Remember in the grammar terms section above when we talked about restrictive clauses (stuff you need or you can’t understand the sentence) and nonrestrictive clauses (you can take them out and still have a meaningful sentence)? This part is why we needed to learn those terms.

Here’s our pattern:

  • Independent clause + restrictive dependent clause = no comma
  • Independent clause + nonrestrictive dependent clause = comma

I think what will help cement the pattern is that arm flourish I mentioned in the previous section. With a restrictive dependent clause, all the words are necessary, so we don’t want to do the arm flourish/insert a comma. We want the reader to keep reading so they can get all parts of the sentence.

Restrictive dependent clause (no arm flourish) example:

Hercule Poirot frowned when Edward Ratchett interrupted him.

Nonrestrictive dependent clause (arm flourish) example:

Countess Helena Andrenyi, played by Lucy Boynton, has very little screen time.

Nonrestrictive dependent clauses are kind of a flavor text, so we want to do the arm flourish/insert a comma. And then we want to alert the reader that the extra stuff (the nonrestrictive dependent clause) is over so there is a second comma at the end of the clause.

Sand on the beach. Text: 6.26 Commas with intervening dependent clauses (two consecutive conjunctions)

Sometimes we get a situation where there’s a dependent clause and a coordinating conjunction. We know from 6.22 (see previous article) that when there’s a coordinating conjunction heading up a clause there’s usually a comma before it. In this case, the coordinating conjunction steals the comma that normally would go before the dependent clause.


Poirot interviewed all the passengers, and if he hadn’t been shot, he might not have solved the case.

Since there are times when dependent clauses do have a comma, it’s easy to see that someone might apply both rules. This would result in a sentence that looks like this:

…passengers, and, if he hadn’t…

Having commas on both sides of the and is one arm flourish too far. We’ve traveled into Jazz Hands Territory.

Chicago does its usual walk back saying that, “strictly speaking, it would not be wrong to add a comma between the conjunctions.” So, you can argue your way into using them, but you need to make a careful decision if your sentence really needs the razzle dazzle of Jazz Hands, or if one arm flourish will do.

Do you love this series and want more? Follow the links below to catch up with the other parts of the series:

Commas the Chicago Way #1
Commas the Chicago Way #2
Commas the Chicago Way #3

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Sand on the beach. Text: Commas the Chicago Way 6.22–6.23.