I came across a sentence recently that illustrates three very common questions about grammar and punctuation. It comes from Lois Lowry’s acclaimed 1993 novel, The Giver, and as you read it, note first how the sentence toggles back and forth between asserting a thought and merely suggesting one. Try to see, that is, the compositional pattern of a clause followed by a phrase three times, with a fourth clause concluding the entire statement. Here’s the sentence: He listened politely, though not very attentively, while his father took his turn, describing a feeling of worry that he’d had that day at work: a concern about one of the new children who wasn’t doing well. (Houghton Mifflin Harcourt, 2014)
Those thirty-nine words put the author at risk of writing quite an unshapely jumble, but the compositional structure she found holds its many ideas together nicely and brings the reader safely through a stormy scene. The first three words comprise an independent clause (a group of words with a subject and verb), and this makes up the only complete thought in the sentence. There follows what is called a parenthetical statement, the phrase though not very attentively, and this part of the pattern enlarges the previous assertion by telling us more precisely just how the subject listened, namely, not very attentively. Parenthetical statements add commentary to something already said, but what they add is not considered essential to the grammatical structure of the sentence. In the technical terms of grammar, they constitute a nonrestrictive modifier, and as such they are always set off by commas—a pair of commas unless at the end of a sentence, where the period will supersede the second comma. Beware that it is a common mistake to write only one comma of the pair. Parenthetical statements may also be punctuated with parentheses or even dashes, but these choices each require special circumstances of their own.
This first clause and phrase combination form the compositional pattern that will recur two more times in the sentence, next in the subordinate clause while his father took his turn followed by the participial phrase describing a feeling of worry, and finally with the relative clause that he’d had that day at work followed by the phrase a concern about one of the new children. The sentence ends with the beginning of a fourth instance of the pattern, the relative clause who wasn’t doing well. If we concentrate now on the second half of the sentence, we can observe two more points of good writing.
The first has to do with the use of the colon. Here, the colon appears between the clause and phrase that make up the third instance of the pattern: that he’d had that day at work: a concern about one of the new children. A colon is used most often to exemplify or specify something that has been said earlier. It is a stronger punctuation mark than the common comma, and so it brings some added attentive energy to the statement being made. This section of the pattern begins with the relative pronoun that, whose antecedent is the noun worry in the phrase immediately before it. We can worry about many things, and so the writer has specified the particular worry with which the subject of the sentence was concerned by presenting it swiftly after a colon, the better to suggest how powerful the worry was.
The other point to observe in this second half of the sentence is the number of the verb in the final clause, who wasn’t doing well. Verbs may be either singular or plural in form, and which of the two forms they assume depends upon the number of the subject—not the number of any other noun that may stand between the subject and its verb. Here, the antecedent of the relative pronoun who is the singular pronoun one, not the plural noun children: one of the children was not doing well, not all of the children, and so the verb should be singular, as it is, to accord with that singular subject.
Lowry’s fine sentence illustrates how integral structure and punctuation are to the meaning conveyed. After we’ve written our first draft, we can analyze what we’ve written to better its shape and force. But it is important to remember that an analysis like the one we’ve just accomplished follows the moment of creation, and serves us best when it makes us conscious of how sentences work, so that our writing mind can in the act of writing find a place for all it discovers.