In our last episode our topic was the clause and when it should be set off by commas; this time we look at phrases. A clause has a subject and a predicate (verb); by definition a phrase does not. A phrase can assume many forms and basically is nothing more than a group of words that relate to each other; it may contain a noun or a verb, or even both, so long as they do not relate to each other as subject and predicate.
The rules regarding phrases are similar but not identical to those relating to clauses. Generally it depends on whether the phrase is essential (restrictive) or non-essential (non-restrictive) to the meaning of a sentence. Whether it is used at the beginning or end of a sentence, a restrictive phrase should not be set off by commas and a non-restrictive phrase generally should be set off. Some illustrations of types of phrases follow (the phrases are in italics in each illustration):
Gerundive. E.g., “The judge dreaded running for public office.”; “Eating dinner is an opportunity to relax.” Here by adding “. . .ing” to a verb and using it as illustrated, the entire phrase becomes the direct object in the first illustration and the subject of the sentence in the second. A gerundive phrase has been called a “verbal noun” and should never be separated from its verb by a comma because all of the words forming the phrase together function as a noun which is either the subject or the direct object of its verb. As such the gerundive phrase is always restrictive, whether appearing at the beginning or end of a sentence. Take a simple sentence, “The boy threw the ball.”; here it is clear that it would be improper to place a comma after “boy” (the subject) or before “the ball” (the direct object); gerundives are simply more complex noun forms, and the same rules apply.
Infinitive. E.g., “To go alone is to take risks.”; “He was determined to climb Mt. Everest.”; “He worked to excel.”. Common characteristics are “to” at the beginning, followed immediately by a verb (please, no split-infinitives; i.e., a non-verb between “to” and the verb). Like a gerundive an infinitive phrase functions as a noun, and the gerundive rules apply: it should not be separated from its verb. (infinitive phrases in italics). It would destroy the flow of the sentences and the thought they contain to set the phrase off by a comma. Again the infinitive phrases are integral and therefore restrictive.
Participial. E.g., “Riding after dark the bicyclist is difficult to see and is at great risk.”; “Mary traveled frequently, flying most of the time.” Again we add “. . .ing” to the verb, but the participial phrase is an adjectival form; i.e., it modifies the subject in both illustrations. Whether the phrase is set off by a comma depends on whether it is restrictive or not; taking “riding after dark” out of the first sentence (above) destroys the meaning of the sentence, and it cannot be separated by a comma. In the second sentence we could delete the phrase “flying most of the time”, and the thrust of the sentence is unchanged; we know that Mary gets about frequently.
Prepositional. E.g., “He saw her at the store.”; “Dick Vermeil, after the Superbowl, retired at the peak of his career.”; “After the fall he arose.”. A prepositional phrase must begin with a preposition and contain within the phrase an object which is usually a noun or pronoun. In the first and third sentences removing the preposition phrases (in italics) would render them non-sensical, but in the second sentence whether “after the Superbowl” is restrictive or non-restrictive could be argued; we have set it off with commas because the sentence still makes sense without the phrase. Your call on that one!
The rules relating to participial and prepositional phrases are not so absolute; while there is a certain latitude, the basic rule relating to restrictive and non-restrictive phrases applies. There will be times when whether a participial or a prepositional phrase is restrictive is arguable and not clear; look at the sentence and determine whether the presence of a comma enhances or impedes the flow of the thought.
Whether they are restrictive or non-restrictive, phrases add zest to our conversations; we change a black and white photo to color.
These are but a sampling of the many types of phrases that might be used; without giving much thought to it, we sprinkle them throughout our conversation and writing routinely. Our goal is to enhance the flow of your prose by the proper placement of the ubiquitous comma in relation to your phrases of every form. (Query: how many phrases in that last sentence? Do you count seven? Go further; how many are there throughout this article?)
– Ken Butera