While walking down the writing road, we come across a side
street. We quickly pause and look both ways before crossing the street. If
there were a sign on the road to tell us to do this, it would be in the shape
of a comma. In the English language, that is exactly what commas do: tell
readers to take a quick pause. Commas have one of the widest varieties of uses
of all punctuation.
Use commas in the following situations:
1.
To help separate two independent clauses joined with a coordinating
conjunction.
For example:
Lucky passed the dog training
easily, but Buttercup had more trouble.
Here, the comma aides the
coordinating conjunction with separating the two independent clauses.
2.
To separate the items in lists.
For example:
Joan bought milk, eggs,
and butter at the store to make the birthday cake.
In the above sentence, the two
commas separate items in the list.
Sometimes there is confusion over whether to use a
comma before the word “and” after the second-to-last item in the list, or use
only the word "and". Careful writers use both the comma and the
"and".
Consider the example from above:
Instead of, “Joan
bought milk, eggs and butter,”
write, “Joan
bought milk, eggs, and butter.”
In the second example, notice the comma
after the second-to-last term in the list.
3. To
separate introductory phrases, clauses, or words from the rest of the sentence.
For example:
Even though Denise was injured,
she tried to ski on her vacation.
In this sentence, the comma
separates the introductory subordinate clause from the main independent clause.
4. After
conjunctive adverbs that connect two independent clauses.
For example:
Jean was furious at Alex for
ruining her binder; therefore, she kicked him when he tried to steal her
lunchbox.
Here, the comma is used after the
conjunctive adverb "therefore". Commas always follow conjunctive
adverbs when used this way.
5. To
introduce relative clauses that begin with the relative pronoun
"which".
For example:
The sunken battleship, which sank during
World War II, had turned into a coral reef.
In this sentence, the comma
separates the relative clause beginning with the relative pronoun
"which". Be careful to use commas only when "which" is used
as a relative pronoun, not when it is used as an interrogative
pronoun.
6.
To set off and conclude appositives.
For example:
Evan, usually a bold and
courageous person, was extremely scared of flies.
Here, the commas set off and end
the appositive "usually a bold and courageous person".
7. To
separate two or more reversible adjectives that modify the same noun (To learn
more about reversible adjectives, see the next grade level concepts).
For example:
One can’t help but smile at the
chubby, enthusiastic man.
In this example, the comma
separates the two reversible adjectives, “chubby" and "enthusiastic”,
both of which are describing the noun “man”.