Consider the structure and meaning of a sentence when punctuating it.
Sentence structure is a basic part of language, and ordinarily, we don’t have to think about it very much. However, when we are not sure how to punctute a sentence, we do have to think about its structure, and usually in terms of three basic questions:
- Is it a simple sentence, a compound sentence, or a
complex sentence? - If the sentence includes a dependent clause or phrase, is
the dependent clause or phrase parenthetical or defining? - Does the sentence begin with the main clause or with
an introductory word, phrase, or dependent clause?
Each of the terms used in these questions is discussed below.
Simple sentences
Mary writes is the simplest sort of simple sentence, containing just a subject, Mary, and a verb, writes. Mary writes me letters is still a simple sentence, though now the verb has the direct object letters and the indirect object me. Mary and John write is also a simple sentence, though it has the compound subject
Mary and John. And Mary writes and telephones is a simple sentence, though it has the compound predicate writes and telephones.
A sentence can get quite long and complicated and still remain a simple sentence. Until recently, Mary and John, my grandchildren, wrote me letters twice a month and telephoned every Sunday afternoon is a simple sentence, even though it includes an introductory adverbial phrase, a compound subject
with an appositive, a compound predicate, a direct and an indirect object for one of the verbs, and an adverbial phrase for each of the verbs. It is simple because in spite of its complexity and its three commas, it still merely connects one subject or set of subjects to one action or set of actions. The following discussion of other types of sentence should help clarify the nature of the simple type.
Compound sentences
John writes, and Mary telephones is a compound sentence. It consists of two clauses, either of which could stand alone: John writes. Mary telephones. They are independent clauses—that is, not only does each have its own subject and predicate (the minimum any clause must have), but neither one is dependent
on the other. A compound sentence is merely a group of two or more simple sentences (or complex sentences, discussed be- low) that have been made one sentence by punctuating them appropriately and often by using a conjunction such as and.
Complex sentences
John, who is my grandson, doesn’t write anymore contains the dependent clause who is my grandson. Mary still gets the urge to telephone just before the rates go up on Sunday contains the dependent clause just before the rates go up on Sunday. Both are complex sentences—that is, sentences with one or more
dependent clauses. The clause who is my grandson is obviously not an independent clause (unless one makes it a question); it is an adjectival clause modifying John. The clause just before the rates go up on Sunday is not independent either; it is an adverbial clause modifying gets the urge to telephone. Each
dependent clause merely modifies something in the main clause.
Compound/complex sentences
They wanted to go on writing and telephoning, but after they moved into my house I told them to stop has an independent clause extending up to the comma and then another independent clause, I told them to stop, at the end, so it is a compound sentence. The second independent clause is modified by the
dependent clause after they moved into my house, so the sentence is also a complex sentence. Thus we have a compound/complex sentence—a compound sentence in which at least one of the independent clauses is modified by a dependent clause.
The meaning of the parts and the meaning of the whole
As can be seen in the examples above, a simple sentence may have quite a lot of internal punctuation and a compound or complex sentence may have very little, although usually a compound sentence has at least a comma. We may now be able to identify a sentence as simple, compound, or complex, but to punctuate it properly we must answer the second and third of the three questions listed at the beginning of the rule—we must determine whether any dependent constructions are parenthetical or defining and whether the sentence begins with the main clause. Essentially this requires us to consider the meanings of the separate parts—the phrases and clauses—that form the sentence and the relationships among these meanings that give the sentence its overall meaning. Writers who punctuate improperly very likely do not al-ways understand what their sentences mean and perhaps do not always understand even what they want them to mean; if they inspected their writing carefully enough to punctuate it properly, they might actually improve their ability to think.
One part of a sentence may be like a parenthetical remark— helpful, perhaps even very important, but not essential to the meaning of the rest of the sentence. Another part may actually define the meaning and hence be essential. A primary purpose of punctuation is to indicate this distinction, as explained below.
Parenthetical constructions
His son, who is a good swimmer, made the rescue contains the parenthetical dependent clause who is a good swimmer. The pair of commas around the clause are, in their effect on the structure of the sentence, exactly like a pair of parentheses:
His son (who is a good swimmer) made the rescue. Omitting one comma or the other would be just as bad an error as omitting one of the parentheses.
Parenthetical constructions are often called nonrestrictive because they do not restrict the meaning of the word or words they relate to but only expand on that meaning; they could be removed from the sentence without changing the basic mean- ing of the subject-predicate combination that makes up the
basic sentence. In the example above, His son made the rescue is the basic sentence, and its meaning is not changed by the
parenthetical who is a good swimmer.
Note, however, that a parenthetical construction is not necessarily of less importance to the overall meaning, the overall effect on the reader, than other parts of the sentence containing it. In The former senator, who will be spending his weekends in prison for the next two years, no longer attends St. Michael’s, the basic sentence is The former senator no longer attends St. Michael’s, and the parenthetical clause does not affect the meaning of the basic sentence, but it certainly affects the overall meaning of the complete sentence. Parentheses themselves often do suggest that what they enclose is a digression or a bit of incidental information that should not distract the reader from the main point of the sentence, but pairs of commas, and especially pairs of dashes, frequently
emphasize what they enclose. The rescue was made by his son, who is a good swimmer contains the same parenthetical clause as the first example. We
don’t use the second comma, because we have reached the end of the sentence and use a period instead, but if we replace the commas with parentheses, it is apparent that the clause is still parenthetical: The rescue was made by his son (who is a good swimmer). When a parenthetical clause begins a sentence, the
first comma is, of course, omitted: Although he swims well, he has no lifesaving training. The second comma—in the example, the one after well—is optional but often desirable, as explained in the discussion of introductory constructions below.
Parenthetical elements don’t have to be clauses; they can also be phrases or even single words, as explained more fully below in the discussion of appositives. His son, John, made the rescue has the parenthetical element John. John, swimming strongly, reached the child in time has the parenthetical element swimming strongly The examples of parenthetical constructions above might lead one to conclude that such constructions must always be set off by punctuation. However, sometimes they are not. In John as well as his brothers has received lifesaving training, the phrase, as well as his brothers, is parenthetical. The phrase
has no effect on the basic meaning, John has received lifesaving training (and it has no effect on the verb has-. We can set the phrase off if we wish, giving the sentence a somewhat different effect, but we don’t have to. The phrase as well as and some others can be so clearly parenthetical, so clearly an interruption, that the signal of enclosing punctuation is not needed.
Defining constructions
His son who is a good swimmer made the rescue is quite different from the earlier example with commas. When the sentence has no commas, the subject is no longer just His son, but a specific son who is a good swimmer, as distinguished from other sons who aren’t. There are no commas because who is a good swimmer is now a necessary, integral part of the sentence, essential to the meaning. Read aloud, the sentence would have no pauses. Similarly, His son John made the rescue singles that son out from others with different names—but see also the discussion of appositives below.
Defining constructions are often called restrictive, because they restrict the meaning of the word or phrase they relate to. Like nonrestrictive elements, restrictive elements can be single words or phrases as well as clauses. Because they are an essential part of the meaning, they should not ordinarily be
separated from the words they relate to by commas—though, as will be explained, they sometimes can and sometimes should be so separated when they begin a sentence and in certain special situations.
It is apparent that only the person who is writing about the water rescue can know whether who is a good swimmer is intended to be restrictive or nonrestrictive, defining or parenthetical. If we punctuate the phrase properly, we make our meaning unmistakable; if we don’t, it is uncertain what we
mean. In speech, we can hear slight pauses for the parenthetical construction and a run-together failure to pause for the defining construction. In writing, the presence or absence of commas (or other marks of punctuation that can play the same role, such as dashes or parentheses) makes the distinction.
His son John who is a good swimmer made the rescue is good news but bad punctuation. The lack of punctuation clearly tells the reader that both John and who is a good swimmer are defining elements, but that can’t be the case, because surely only one son is named John. The clause who is a good swimmer must be considered a parenthetical element and thus be set off with a pair of commas or other marks. The word John may be either parenthetical or defining, depending on whether there is only one son or more than one. If it is defining, it should not be set off: His son John, who is a good swimmer, made the rescue. If it is parenthetical, it ordinarily should be set off—His son, John, who is a good swimmer, made the rescue—but see the discussion of appositives below.
In His son, the one who is a good swimmer, made the rescue the interrupting construction is obviously defining—it pins down which son is meant—but it just as obviously requires the commas, unlike the defining constructions in earlier examples. The reason is that the one who is a good swimmer is actually an alternate subject of the sentence; The one who is a good swimmer made the rescue is as grammatically valid a sentence as His son made the rescue. The complete sentence has two beginnings and one ending, and the commas are necessary signals of the second beginning. Although careful writers
generally avoid having to begin sentences twice to make their meaning clear, alternate subjects are sometimes employed for rhetorical effect: This sentence, this much-punctuated sentence, this s elf-interrupting syntactical situation, this tedious example, is a tedious example.
Parenthetical and defining appositives
An appositive is a noun, or a group of words acting as a noun, that immediately follows another noun to define it or further explain it. My friend Mary is getting married uses Mary as a defining appositive, narrowing down friend to a specific friend, and no commas are used. Mary, my friend from school, is getting married uses my friend from school as a parenthetical appositive, and parenthetical commas are used. Note that a defining appositive restricts the meaning and makes the word it is in apposition to more specific, whereas a parenthetical appositive, though it may clarify and elucidate meaning, does not really restrict it. Mary in itself means a specific person; my friend from school may supply helpful additional information, but it doesn’t make Mary any more specific.
When a noun and another noun in apposition to it are both completely specific, the noun in apposition is considered parenthetical: My husband, John, is at work; John, my husband, is at work. Both John and my husband are completely specific.
My sister Mary is getting married indicates by the absence of commas that Mary is defining—that is, that there is more than one sister. My sister, Mary, is getting married indicates by the presence of commas that Mary is not defining but merely parenthetical—that is, that there is only one sister, whose
name is provided as additional but not essential information. The principle of setting off parenthetical appositives and not setting off defining appositives is very important. We cannot punctuate correctly without understanding it. Nevertheless, we do not always have to observe it to punctuate correctly.
Parenthetical commas can often be omitted in phrases such as my husband John and my sister Mary, even though there could be only one husband and there may be only one sister. My husband John can be considered a unit, somewhat like my Uncle Bob, rather than an ordinary case of noun and appositive; it often would be spoken without pauses. My sister Mary can also be considered a unit when the existence of other sisters is unknown or irrelevant; and conversely, my sister, Mary, with Mary treated as parenthetical, may be quite all right even if there are a dozen other sisters as long as Mary is the only possible one meant in the context. Some writers and editors always try to make the punctuation conform to the genealogical facts, but forcing such conformity may be a violation of common sense. Usually, we can insert or omit commas in such phrases by ear—but only if we understand the principle we are observing or not observing. If we don’t understand the principle, we don’t have a trustworthy ear.
In other situations, failure to follow the principle is indefensible. In his essay “Self-Reliance,” Emerson celebrated individualism is a gross error. Since Emerson wrote more than one essay, “Self-Reliance” is defining, not parenthetical, and it should not be set off by commas (though the second comma is
desirable, as explained below). Similarly, An old saying, “Haste makes waste,” was stamped on his forehead is correct, but The old saying, “Haste makes waste,” was stamped on his forehead is grossly wrong. The error is particularly common when the appositive is in quotation marks, perhaps because people
with a hazy grasp of punctuation confuse apposition with direct quotation, which, as explained in Rule 2-11, is usually preceded by a comma: Emerson said, “Self-reliance is an American characteristic.” However, errors with titles also occur frequently when the title is in italics rather than enclosed by quotation marks, as in Faulkner’s novel, The Mansion, is part of a trilogy. The converse error, omitting commas when the subject of the sentence is already completely specific and the appositive is therefore necessarily parenthetical, as in Smith’s only poem “My Dog” was never published, seems to be rare.
Introductory constructions
An introductory construction is anything that precedes the main clause, or the first independent clause, of a sentence. It may be a single word, such as However-, it may be a phrase, such as In view of the circumstances-, it may be a dependent clause, such as When I’m ready It may be either defining or
parenthetical. Frequently an introductory construction is followed by a comma, which serves as a signal that the main clause is about to begin.
I’ll call you when I’m ready contains the defining dependent clause when I’m ready. When I’m ready I’ll call you puts the dependent clause first, as an introductory construction; When I’m ready is still a defining clause, restricting the meaning of I’ll call you, but because it is introductory it can be set off with
a comma. Thus after an introductory construction, a comma is not the signal of a parenthetical element but simply a clarify- ing pause.
A comma is not always required following an introductory construction—When I’m ready I’ll call you is fine since the introductory clause is short and very closely related to the main clause. The comma can sometimes be omitted even when the introductory clause is parenthetical, as in Although
he swims well he has no lifesaving training, which might benefit from a comma after well but does not strictly require it. Commas or omitted commas are clear indications of parenthetical or defining constructions only when the constructions are not introductory.
We can usually “hear” whether the comma is desirable or necessary following an introductory construction. When we’re eating local politicians are not to be discussed requires a pause after eating in speech and a comma after eating in writing, to keep local politicians from being momentarily misunderstood
to be the direct object of eating. Dinner being over we began to quarrel requires a comma after over to separate the absolute phrase Dinner being over from the main clause; an absolute phrase, even though it is not an independent clause, is independent of the sentence containing it, and its independence is honored in speech with a distinct pause.
We can also hear when the comma is not permissible, as in In the dining room, were twelve quarrelsome people, which should not have the comma after room. In such cases, the opening words are usually not an introductory construction at all but a displaced part of the predicate of the main clause
Listening a little harder, we can hear when a permissible comma is not desirable, as in A moment later, he left the room, and we discussed the issue more openly-, omitting the comma after later would make it more apparent that the introductory phrase modifies only he left, not we discussed, for which it is
not a very suitable modifier—it indicates a point in time, and we discussed indicates an activity that extends over time. Without such conscious analysis, in saying the sentence we would tend not to pause after later but to pause after room, and good punctuation can be similarly unconscious—though we
should expect to devote more conscious attention to writing than to speech, and analysis never hurts.
Therefore, however, in addition, and many similar words and phrases are usually followed by a comma when they are used to introduce a sentence: Therefore, let’s talk about something else. There is some flexibility when such words and phrases are used in a compound sentence to introduce a second clause:
Tempers were beginning to rise, and therefore we changed the subject. A comma after therefore would not be incorrect, but it would give the sentence a loose look, with no distinction made between the major pause after rise and the minor or missing pause after therefore. Tempers were beginning to rise; and
therefore, we changed the subject uses a semicolon for the major pause and a comma for the minor one, which is correct but gives the sentence more punctuation than it really needs. (Grammar books of a century ago would require a comma between and therefore as well—an example of the changes
that ”proper punctuation” has endured; we use lighter punctuation today.) When we use introductory constructions in speech, we are often almost forced to pause after them if the following word is important to the grammar and meaning—a noun or an adjective, say—and is therefore stressed: After Munich / war seemed unlikely. We often aren’t forced to pause if the following word is unstressed, as the articles a and the nearly always are: After Munich a war seemed unlikely-, After Munich the war preparations abated. We can keep this fact in mind when we are deciding whether to set off introductory phrases, but it can’t be
the only basis for the decision; When we’re eating a local politician is not to be discussed requires a comma after eating just as much as the slightly different earlier example does. The most important thing to remember about introductory constructions is simply that they are introductory—they precede the beginning of the main clause—and whether they are defining or parenthetical and no matter how vital they are to the overall meaning, they may require or at least benefit from a comma to set them off.
The goal: punctuation that reinforces structure
This long rule is intended to increase the reader’s awareness of the structure of sentences—of the ways in which the parts of a sentence combine their meanings to build the meaning of the complete sentence. Along the way, it has demonstrated ways in which punctuation, particularly the comma, can clarify and sometimes change sentence structure and meaning. Punctuation does not always indicate structure, and many of the other rules in this chapter are concerned with its other functions. However, bad punctuation—not just the occasional error with an apostrophe but truly bad punctuation, consistently bad punctuation, such as one is apt to see in the letters column of a small-town newspaper, in committee reports, in almost any written effort that has not been professionally edited—is nearly always, I think, the result of failure to consider how sentences are structured and how punctuation can
strengthen rather than contradict structure.
It seems a pity that only professional editors, and not all of them, can be expected to punctuate well. Professional editors have no monopoly on intelligence, on analytic ability, or on “communication skills”—on language. Nor should they have a monopoly on punctuation, which is a vital part of the written
English language. Editors have acquired their monopoly because many people who write, even many who write professionally, do not take punctuation seriously. They are quite willing to admit that they don’t know much about it; they even make a virtue of their ignorance—they’re concerned with important matters, with the broad picture, with the main thrust, and they gladly leave punctuation to the drudges who concern themselves with fussy details. They would be less willing to admit that they don’t know much about relating ideas to one another, about language, about thinking. But in boasting of ignorance of
punctuation, they may unknowingly also be admitting to a significant deficiency in these broader areas.
“Thank you for taking the time to explore this topic with us! We hope you found the information helpful and insightful. Have any thoughts, questions, or additional examples to share? We’d love to hear from you in the comments below!
Don’t forget to spread the word by sharing this blog with your friends, family, and colleagues. Together, let’s continue to learn, grow, and connect with the world around us. Happy reading and sharing!”
