2. A comma is the most important punctuation mark for
ensuring clarity in a sentence. However, it is often
incorrectly used, which can sometimes have comical
results.
3. Using commas correctly ensures that the reader
understands the meaning the author intends to convey.
There are a few strict comma rules concerning usage,
but many of the conventions are merely typical
practices.
Exceptions exist, so authors should make the best
decisions possible in the interest of clarity. Nonetheless,
here are the most common comma rules:
5. Three or more items (single words or phrases)
in a series should be separated by commas,
including the final item, which comes after the
conjunction (almost always and or or). This final
comma is known as a serial comma.
Consider the following example of a comma
series:
I must remember to buy flour, eggs, milk, and
chocolate if I'm going to bake that cake.
7. An independent clause is a group of
words that can stand alone as a
sentence. Two examples of an
independent clause are:
We would all love to see the movie. I
think we can still make it on time if we
hurry.
8. When two independent clauses are joined by a
coordinating conjunction (and, but, or, nor, for, so, and
yet), a comma precedes the coordinating conjunction.
conjunction.
We would all love to see the movie, and I think we can still
make it on time if we hurry.
9. However, when both independent clauses are
short and there is no danger of misreading the
sentence, the comma can be omitted.
The meeting ended and I went to the park.
11. A dependent clause is exactly what it sounds
like: a group of words that depends on another
clause to form a complete sentence. When a
dependent clause follows an independent
clause to make one sentence, no comma is
needed.
We shuffled into the dark theater and noticed
the previews were just ending.
12. However, some sentences begin with a
dependent clause. A comma is needed
following this clause, as is shown in the
following example.
If you don't want to play the recorder,
please raise your hand.
13. Comma Rule #4: Using a comma
following an introductory
word group
14. Some sentences open with a group of words that
explain when, where, why, or how the main action
of the sentence occurs. A comma follows this
introductory word group and explains to the reader
that the main part of the sentence is about to
begin. Here's a good example:
On the edge of the stream, a male frog croaked out
his mating song.
15. Some sentences begin with a phrase describing the noun
or pronoun that immediately follows. A comma follows
this introductory phrase.
Knowing he was allergic to melon, Paul did not eat the
fruit salad.
Some sentences begin by directly addressing someone. A
comma follows the name.
Elise, I love your dress!
16. Some sentences begin (or end) with words that answer or
ask a question. A comma follows this word or phrase if it is
at the beginning of the sentence and precedes it if the
phrase is at the end.
Yes, he is going to the play.
That dog behaved well, didn't he?
Some sentences begin with mild interjections, which should
be followed by a comma.
My, he is tall.
18. Phrases that interrupt the sentence to provide information
that is not necessary to the main idea of the sentence (also
known as non-restrictive phrases) are set apart with commas.
Here are a few examples:
19. The band, which won several awards last year,
played at the stadium all night long.
The garden, with its tall wooden fence and
muddy pathways, produced a large crop of
tomatoes.
The current manager, it seems, was not the
best one for the job.
21. Expressions preceding or following direct
quotations are set apart by commas.
"I will have a glass of red wine," she told the
waiter.
"A rose by any other name would smell as
sweet," William Shakespeare wrote.
22. For such an inconspicuous little mark, the comma
performs a wide variety of functions in a sentence. If
you are still unsure about commas, consider taking our
top-notch online grammar course, GrammarCamp.com.
24. Commas remove ambiguity and ensure that readers understand
the meaning the author wants to convey. Let's continue looking
at some additional grammatical constructions that call for
comma usage.
25. A comma separates the month and date from the year.
On March 23, 2009, David and Alice will be married.
However, if the date is written in the inverted style, or if
only the month and year are given, no comma is needed.
The new law goes into effect 30 May 2010.
October 2006 was the month we went over our budget.
Using Commas: Dates
26. A street address, city, and state or
province are separated by
commas.
I am moving to 45 Magnolia Lane,
Toronto, Ontario.
Using Commas: Addresses
27. In numbers longer than four digits, commas
separate the numbers into groups of three,
starting from the right side.
15,000
10,000,000
This convention is predominantly found in
North American and British English. Numbers
may be punctuated differently in other
languages.
Using Commas: Numbers
28. If a title follows a name,
a pair of commas
separates it from the
rest of the sentence.
Michael Smith,
paleontologist, will lead
the excavation.
Using Commas: Titles
29. Coordinate adjectives are adjectives that modify a noun on their own.
Commas separate two or more coordinate adjectives.
It's going to be a long, hot, busy summer.
Cumulative adjectives depend on one another for meaning. Do not use
commas to separate two or more cumulative adjectives.
Three large red trucks were headed for the entrance ramp.
Using Commas: Coordinate Adjectives (But Not
Cumulative Adjectives)
30. What if you aren't sure whether you're dealing with coordinate
or cumulative adjectives? Scribendi.com's editing services
suggest trying these two tests:
1. If you insert the word "and" between the adjectives, does
the sentence still make sense?
2. If you list the adjectives in a different order, does the
sentence still make sense?
If you answered yes, you have a list of coordinate adjectives,
and they should be separated by commas. If you answered no,
you have a list of cumulative adjectives, and they should not be
separated by commas.
31. An appositive is a noun or noun phrase that
renames a nearby noun. The need for commas
around an appositive depends on whether it is
restrictive or non-restrictive.
Using Commas: Non-Restrictive Appositives (But Not
Restrictive Appositives)
A non-restrictive appositive is a phrase that restates
information already given.
32. The phrase my oldest son can only refer to one person, so
the addition of his name is not necessary for us to
understand the meaning of the sentence. The appositive
could be removed, and we would still know who won the
race. Commas are used to set apart non-restrictive
appositives.
For example:
"My oldest son, Michael, won the race."
33. Shakespeare's play Romeo and Juliet is a classic
tale of forbidden love.
Since Shakespeare wrote more than one play, we need
the appositive Romeo and Juliet to clarify which play the
author is discussing. If the appositive were removed, the
meaning of the sentence would be unclear. Commas are
not used to set apart restrictive appositives.
A restrictive appositive is a phrase that clarifies an
ambiguity in the information already given.
For example:
34. Commas can ensure clarity and eliminate wordiness. Sometimes a comma will
prevent what grammarians call mistaken junctions, when a reader groups
words in a way other than that which the author intended.
Using Commas: Ensuring Clarity
35. Soon after the dinner was interrupted
by a robbery.
She saw the spider that climbed the
wall and gasped.
To Sally Frank was an insufferable
person.
Soon after, the dinner was
interrupted by a robbery.
She saw the spider that climbed the
wall, and gasped.
To Sally, Frank was an insufferable
person.
VS.
VS.
VS.
Notice the difference in clarity when commas are used properly:
36. The comma is a powerful punctuation mark with an impressive array
of uses. No matter how the comma is used, its purpose is to make
meanings clear. Authors struggling with a gray area of comma usage
should consider the meaning they hope to convey and make the
choice that seems best. Remember, clarity always wins out over strict
adherence to comma rules.
To learn more about commas, check out GrammarCamp.com, a
grammar training course that covers everything you need to know
about English grammar.
To sum it all up . . .
