Use Commas to Clarify Whether Information Refers to the Subject or an Object of a Sentence


Correct comma usage

Posted by Jake Magnum | September 21, 2018 | Comma Corner


A sentence structure that I often see fiction writers use looks something like this:

I sat on the park bench reading a book.

We start with a noun, then a verb and an object, followed by an -ing phrase.

This structure is perfectly normal and often leads to a sentence that is easy to read. The example above is particularly easy to read because, between the subject (“I”) and the object (“the park bench”), only one of these can logically do what is described by the -ing phrase. It is clear that I am reading the book, as it is impossible for a bench to do so. As such, it does not much matter whether we include a comma before the -ing phrase.

The two sentences that follow mean the same thing:

I sat on the park bench reading a book.

I sat on the park bench, reading a book.

Writers must be careful, though, when the -ing phrase could refer to either the subject or object.

The following is such a sentence:

I chatted with some random girl smoking a cigarette.

Logically, either I or the girl could be smoking the cigarette. The natural way of reading this is that the noun closest to the -ing phrase performs the action. In the example above, the random girl is smoking.
In this case, inserting a comma before the -ing phrase changes the meaning of the sentence. In the following example, I am now smoking:

I chatted with some random girl, smoking a cigarette.

(This, however, is not the most graceful way of writing this sentence. Better examples are given at the end of this article.)

Therefore, when you write sentences using this structure, be sure to check whether you should be using a comma.
There is a caveat to the first example. I said that it does not matter whether we use a comma if the -ing phrase can only logically refer to one of the nouns that come before it. However, for long -ing phrases, it is usually a good idea to treat the phrase as though it could refer to either the subject or the object, and use a comma accordingly.

The following example illustrates why you should do this:

I chatted with some random girl smoking a cigarette and trying to remember how my life had even gotten to this point.

The -ing phrase surely refers to the narrator, not the girl. (The girl cannot be wondering how the narrator’s life got to this point.) Still, it is a mistake to leave the comma out of this sentence.

With no pause between the words “girl” and “smoking,” the reader will naturally associate “smoking” with “girl,” as these two words are right next to one another. The reader won’t realize that it is the narrator who is smoking until reaching the words “my life.” The reader will then have to pause to readjust or backtrack, which is obviously something we don’t want our readers doing.
As a final note, we can do more than simply adding a comma to make it extra clear that the subject is performing certain actions in this type of sentence:

We can use a word or phrase, such as “while” or “as I was,” instead of a comma.

I chatted with some random girl while smoking a cigarette.

We can move the -ing phrase to the beginning of the sentence.

Smoking a cigarette, I chatted with some random girl.

These techniques work well for this purpose, though they do have small drawbacks. Adding “while” makes the tone slightly more formal, which might not be ideal. And if the -ing phrase is long, putting it at the beginning of the sentence can ruin the pace of a scene.
In any event, if you often write these kinds of sentences, you now have a lot of information that you case use when crafting them. I hope you found this article helpful. Thanks for reading!