Sentences can be complicated. They can contain many ideas, communicate many messages to the reader. They can be confusing. With commas in the right places, however, complicated sentences become clear.
Let’s look at a complicated sentence and see what the commas do. This sample, from the book Antrax by Terry Brooks, contains a whopping five messages, but it is easy to understand because Brooks is a comma master and knows how to use commas right.
A little later, feeling uneasy, he rose and peered out into the ruins of the city, searching the darkness.
This sentence is about the character Quentin. It describes when he acts, how he feels, his two actions, and his purpose. In all, this is five different messages to the reader. We, the readers, can easily understand the entire sentence because of the three commas. We’ll look at them one at a time.
The first message in this sentence, a little later, describes when the action occurred. It is before the subject, so it is introductory, and it describes the main actions, so it is adverbial. We see that it is followed by a comma, which demonstrates Zen Comma Rule G: Put a comma after introductory phrases and clauses. The comma alerts the reader that the introductory description is finished and that a new message is about to be communicated.
The second message is feeling uneasy. This describes the entire situation being communicated in the sentence. It communicates Quentin’s overall state of being. Because it does not modify just one part of the sentence but the sentence as a whole, it serves as an absolute phrase. We see that it is separated from the rest of the sentence by commas, which demonstrates Zen Comma Rule AB: Separate absolute phrases with commas.
Third and Fourth Messages (main sentence):
The third and fourth messages form the main idea of the sentence, containing the subject and a compound predicate: he rose and peered out in to the ruins of the city. This has no commas, which is correct.
One common mistake is to separate the subject he from the predicate, though this is unlikely when the subject is short. This has no comma after the subject, which follows Zen Comma Rule AJ: Don’t use a comma to separate the predicate from the subject.
Another common mistake is to separate the two parts of the compound predicate with a comma. In this case, the first part is rose and the second part is peered out into the ruins of the city. If we put a comma after rose, we separate the second part of the predicate from the subject, which is wrong. By leaving out the comma, we keep the second part connected to the subject, which follows Zen Comma Rule AK: Don’t use a comma to separate two parts of a compound subject.
Finally, the last message is searching the darkness. It immediately follows city, but it does not describe city. Rather, it describes Quentin. To make sure the reader doesn’t think the city is searching the darkness, we separate it with a comma, which follows Zen Comma Rule W: Use commas to separate final descriptions that don’t refer to the immediately preceding text.
Commas and Clarity:
Although this is a complicated sample (and this is a rather long post), we see that the commas make the meaning clear. We also see that the commas follow clear guidelines. They are not placed haphazardly but are carefully placed to ensure reader understanding.
Each of these comma uses (or non-uses) is described more fully in Zen Comma.
Need help with commas? Get Zen Comma, a guide to the 17 major uses and misuses of commas. Read more about Zen Comma.