How to Punctuate Introductory Phrases

By Mark Nichol

With a comma. Always. Except when you don’t. Perhaps I should annotate that: In the overwhelming majority of cases, follow an introductory phrase at the beginning of a sentence with a comma.

Adverbial Conjunctions
Eight classes of adverbial conjunctions exist, and a comma should generally follow one in every class. Each of these sentences includes an example of one such part of speech from each class:

Addition: “Finally, I reached the station.”

Comparison: “Similarly, chickens are omnivores.”

Concession: “Naturally, you’ll want to see for yourself.”

(Note, however, that however isn’t always an adverbial conjunction. In this sentence, it’s an adverb modifying important: “However important you think it is, I’m not giving him the message right now.”)

Contrast: “Nevertheless, he didn’t go into detail.”

Emphasis: “Of course, she’ll be there, too.”

(An exception can be made for this particular phrase: There’s a subtle but distinct difference between “Of course, you’ll want to do it your way” and “Of course you’ll want to do it your way.” In the first sentence, your is stressed; in the second, course, perhaps accompanied by a sneer, is emphasized, with a secondary stress on your — and likely an exclamation point to signal emotion.)

Example: “For instance, the floor was swept but not mopped.”

Summary: “In conclusion, I recommend that we approve the measure.”

Time sequence: “At last, we saw their car approaching.”

(Some writing and editing guides suggest that short introductory phrases don’t require commas; often, such brief modifying phrases involve time: “Yesterday I saw a ghost,” for example, or “In 1492 Columbus sailed the ocean blue.” I recommend, though, use of commas in such cases. Otherwise, the exception to the rule is rather arbitrary; how long does a short phrase need to be before it merits a comma? And why omit commas in some cases and include others?)

Hence, Still, Then, and Thus
Another class of words may or may not be followed by a comma depending on subtle differences:

“Hence the name,” but “Hence, I was back where I had started.”

“Still the waters raged though the rain had ceased,” but “Still, I try one more time.”

“Then I tried to start the car again,” but “Then, I would have acted differently.”

“Thus we are back where we started,” but “Thus, I concede the point.”

Infinitive Phrases
“To get there, turn right at the second intersection.”

Participial Phrases
“Under the circumstances, I cannot allow it.”

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13 Responses to “How to Punctuate Introductory Phrases”

  • Dayf

    How can you please explain the difference between these two?

    “Thus we are back where we started,” but “Thus, I concede the point.”

    Thanks.

  • Dayf

    Can you please explain the difference between these two?
    “Thus we are back where we started,” but “Thus, I concede the point.”
    Thanks.

  • Cindy Cotter

    Oh, heck, I’d never heard of an adverbial conjunction before, and I don’t think I usually follow them with commas. Bummer. This is gonna take a little mulling over.

  • Mark Nichol

    Dayf:

    Good question. On further reflection, I would punctuate after thus in the first example, too. A better example of a sentence in which no comma should follow thus is the translation of “Sic semper tyrannis” (“Thus always to tyrants”), where thus, though an adverb, seems to act like a pronoun — “This is what happens to tyrants.”

  • Sally

    Very interesting.

    I teach my students that “if omitting a comma does not violate the sense, then omit it.”

    Thus we would avoid what one of my teachers called ‘tadpole-itis,’ a swarm of commas infesting the page.

  • Frank Elliott

    Sally,

    I concur.

  • Tom Jacobs

    Isn’t a comma the typographical rendering of a pause when speaking? Thus a comma should be inserted whenever you hold your breath?

  • Oliver Lawrence

    Thanks, I enjoyed reading your article.

    There’s also the category of cause and result, such as “accordingly”, “as a result”, etc.

    BTW, “Under the circumstances” is a prepositional phrase, not a participial one.

    And I believe these things are more commonly called “conjunctive adverbs”, as in terms of word classes/parts of speech, strictly speaking they are adverbs (or adverbial phrases), not conjunctions (see ‘Writing with Style’, Oxford 2010, and http://en.wikipedia.org/wiki/Conjunctive_adverb, and compare Ghit counts for the two phrases).

  • Oliver Lawrence

    The special cases you raise where a comma is not required or is optional are particularly interesting.
    In the case of conjunctive adverbs not being used as an introductory phrase (eg “however important it may be, don’t do it – where “however” is not an introductory phrase but “however important it may be” is; and “hence the name”), the general rule about using commas with introductory phrases remains intact.
    And for introductory phrases involving time, a good rule of thumb for when the comma can/should be omitted is to consider whether you would make even the slightest pause when you speak the phrase: if not, a comma can safely be omitted. Less confident writers can simply use the comma all the time and they will not be wrong.

  • Amanda

    “Of course, you’ll want to do it your way”
    “Of course you’ll want to do it your way.”
    In the first sentence, your is stressed; in the second, course, perhaps accompanied by a sneer, is emphasized, with a secondary stress on your — and likely an exclamation point to signal emotion.

    If what I learned about punctuation is correct, comma signifies a pause, and whichever follows is emphasized. But according to what you said, is what I learned wrong? Thanks.

  • Mark Nichol

    Tom and Amanda:

    Although many people don’t consider a comma as a pause marker a technically valid role, it often serves that purpose. (But not everybody pauses in the same place.)

  • Teah

    Sally and Frank,
    If you teach your students that “if omitting a comma does not violate the sense, then omit it.” You are teaching your students to punctuate incorrectly. The rules are only meant to be broken after you know them.
    Commas play a vital role in sentence structure.

  • Robert Traynor

    The whole purpose of punctuation is to prevent a misreading of what is written and to emphasize certain parts of what is written. If I were to omit the comma in the following sentence, would the meaning of the sentence be lost or changed?

    Finally, he entered the room.

    With or without the comma, the meaning of the sentence remains the same. Therefore the comma has a purely stylistic purpose. This means you can add it if you wish to emphasize “finally,” or you can omit it. I would do the latter.

    The current trend is to reduce the number of commas in your writing, which I think is a very sensible trend. Misreadings excepted, there is no practical (as opposed to stylistic) value to placing commas after introductory words such as “naturally,” “ironically,” and “unfortunately” and introductory phrases such as “early in the morning.”

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