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Commas, Introductory


Introductory commas come between an initial word, phrase, or dependent clause and the main (independent) clause of a sentence. Their purpose is to signal the end of this introductory material and the arrival of the main subject and verb, helping readers to parse your syntax accurately on the first read.

To identify whether a sentence needs an introductory comma, locate the main subject—the one in the independent clause of your sentence—plus any modifiers appended to it. If any material precedes this main subject, insert a comma:

  • In the wake of the decisive naval engagement at Dan-no-ura, the victorious Minamoto clan established Japan’s first shogunate.

(In a sentence with multiple independent clauses, this comma will instead be a FANBOYS comma or a colon or semicolon.)

Note that a sentence can have more than one distinct introductory word, phrase, or clause; in such cases, place a comma after each.

 

Introductory Commas Practice Exercises

Which sentences need introductory commas? Where?

  1. If it is raining spaghetti will be served.
  2. Even if you have a dog a cat or a parrot is a nice addition to your menagerie.
  3. Whether the agreement will remain in effect will depend to a large extent on the testimonies next week.
  4. Import prices will likely continue to rise whether or not the agreement remains in effect.
  5. In 1815 however Napoleon abdicated following his defeat at the Battle of Waterloo.
  6. In 1815 however Napoleon had prepared for the encounter he was defeated by Wellington.

 

Answers

  1. If it is raining, spaghetti will be served. ("Spaghetti” is the main subject; without the comma, we might initially think it could rain spaghetti.)
     
  2. Even if you have a dog, a cat or a parrot is a nice addition to your menagerie. (“A cat or a parrot” is the main subject; with no comma, we might read the beginning as an unpunctuated list of three animals you might already have. Even with the intro comma, it could still sound like a list at first, which is a good argument for consistently employing the serial comma.)
     
  3. No intro comma needed: “Whether the agreement will remain in effect” is the main subject here, followed by the main verb, “will depend”; there is no introductory material before the main subject. Compare this sentence, in which the “whether” is part of an introductory dependent clause: “Whether or not the agreement remains in effect, import prices will likely to continue to rise.”
     
  4. No intro comma needed, as the independent clause comes first.
     
  5. In 1815, however, Napoleon abdicated following his defeat at the Battle of Waterloo. (“In 1815” and “however” are discrete introductory particles—one indicating time, one indicating tension or contradiction; each, therefore, gets its own introductory comma.)
     
  6. In 1815, however Napoleon had prepared for the encounter, he was defeated by Wellington. (“In 1815” still gets its introductory comma, but, this time, “however” introduces a long dependent clause; we don’t arrive at the main subject and verb until “he was defeated.”)
     

Further Practice and Other Introductory Comma Links

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All-Topics Index


The following index makes searching for a specific topic easier and links to the appropriate place in the sequenced material. We think we have most of them, but please email us at writingcenter@nps.edu if we are missing something!

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A

abbreviations

abstracts

academic writing

acronyms

active voice

apostrophes

argument

article usage

assignments, understanding them

audience

 

B

body paragraphs

brainstorming

building better sentences tips

 

C

citations

citation styles

clarity

clustering

coaching sessions, about

colons

commas, FANBOYS

commas, introductory

commas, list

commas, nonessential elements

commas, Oxford

commonly confused words 

compare-and-contrast papers 

concision

conclusions

conjunctive adverbs

coordinating conjunctions

copyright and fair use

critical thinking  

 

D

dangling modifiers

dashes

dependent marker words

double submission of coursework

drafting

 

E

edit your own work

editing – outside editors

exclamation points

executive summary

 

F

FANBOYS

FAQs

footnotes

free-writing

 

G

gerunds

grammar

group writing

 

H

hyphens

 

I

ibid.

introductions

 

J

Joining the Academic Conversation

 

L

LaTeX

library liaisons 

literature reviews 

logic and analysis 

 

M

memos

methodologies

 

N

note-taking

numbers

 

O

organization

outlining

Oxford comma

 

P

paragraph development 

parallelism

paraphrasing

parts of speech

passive voice

periods

persuasion

phrases and clauses

plagiarism, how to avoid through citations

plain language

polishing

prepositional phrases 

prepositions

pronouns

punctuation

purpose of research

 

Q

questions

quotation marks 

quoting

 

R

reading with intent

redundancies                                                                

reference software

reflection papers 

research

research questions

reverse outlining 

revising passive voice into active voice

revision

roadmaps                                            

run-on sentences 

 

S

self-citing

semi-colons

subjects, grammatical

significance

so-what?

spelling

standard essay structure

STEM/technical writing 

style

subject/verb agreement

 

T

technical writing

that vs. which

thesis writing

thesis advisors

thesis process overview

thesis process tips

thesis proposals – common elements                                                     

thesis statements

tone, professional

topic sentences 

transitions

types of papers

 

U

United States or U.S.?

 

V

verbs and verb tense

 

W

which vs. that

Why write?

writer’s block 

writing process