3. The Sentence
In a previous module, we learned that a sentence has two parts:
1. A subject
2. A verb
The subject is the person or thing completing the action (always a noun
or pronoun) while the verb is the action being completed.
Sentence must have both elements or they are considered sentence
fragments.
4. Sentence Boundaries
We’ve also learned that sentences have beginnings and ends and that
we must stay within those boundaries to avoid these common errors:
1. Comma Splices
2. Fused Sentences
Fused sentences incorrectly combine two independent clauses without
any punctuation while comma splices combine two independent
clauses with only a comma, also incorrect.
To correct these errors, you can add a period or semicolon between
the clauses or combine the clauses with a comma + a FANBOY or by
making one of the clauses dependent with a subordinating
conjunction.
5. Comma Rules
The following rules will help you control overall use of commas in your
writing. This condensed lesson is designed to give you a quick
reference as you right. If you find it easier, you may also download
this lesson as a handout for printing.
6. Rule #1: Use a comma to connect
two independent clauses with
a FANBOYS
IC + FB + IC =
Comma
This is a review. You already know that a comma and a coordinating
conjunction correctly connects two independent clauses, as in this example:
Traffic was heavy in the morning, so I got to class late.
Here, “so,” one of our FANBOYS connects the first and second clauses of the
sentence, which are both independent. Remember – BOTH sides must be
independent for the comma to be necessary.
*Sometimes it’s helpful to use an equation to remember comma rules such
as IC + FB + IC = Comma. IC stands for independent clause and FB for
FANBOYS.
7. Rule #2: Use a comma when a
dependent clause precedes an
independent clause
Dependent clauses are those that require an independent clause to
be complete. They contain subordinating conjunctions such as
“because,” “although,” “since,” and “if” (and others!). When a
dependent clauses comes BEFORE an independent clause in a
sentence, use a comma between them, as in this example:
Because traffic was heavy in the morning, I was late for class.
Here, “because” indicates that the first clause is dependent on the
second, independent clause. Since it comes first in the sentence, we
use a comma to separate them.
DC + IC = Comma
8. Rule #2: More!
You must be careful with Rule #2. You only use a comma between
dependent and independent clauses when the dependent clause
comes first. If the independent clause comes first, no comma is
needed, as in this example.
I was late for class because traffic was heavy in the morning.
We have a dependent clause here, the same one as before, but this
time it follows the independent clause. In this case, you do NOT use a
comma.
IC + DC =
NO Comma
9. Rule #3: Use Commas to
Separate Non-Essential Elements
Non-essential elements are parts of the sentence that are additional
information. They might be introductory elements or modifying
information. You might also know these elements as “interrupters.”
Let’s look at an example:
That Tuesday, which happens to be my birthday, is the only day I can
meet.
In this sentence, the phrase “which happens to be my birthday” is a
non-essential element. It provides the reader with more information
but it is not required for the sentence to make sense. When you have
non-essential elements, use a comma (or commas) to separate them
from the main part of the sentence.
IC + DC =
NO Comma
10. Rule #3: More!
To determine whether an element is non-essential, take it out of the
sentence. If the sentence still makes sense and you haven’t changed its
meaning, the element isn’t needed. Both examples here convey the same
main idea:
That Tuesday, which happens to be my birthday, is the only day I can
meet.
That Tuesday is the only day I can meet.
Non-essential elements can appear anywhere in a sentence – in the
beginning, the middle, or the end. And in all cases, a comma (or commas)
is needed to separate it.
I can only meet on Tuesday, which happens to be my birthday.
11. Rule #4: Do NOT use a comma to
separate essential elements of
the sentence
Sometimes phrases that convey additional information are needed for the
sentence to make sense. These are essential elements, and you should not use a
comma to separate them from the main part of the sentence.
The book that I borrowed from you is excellent.
We might be inclined to think the phrase “that I borrowed from you” is additional
information in this sentence, but what happens when we take it out? Does the
meaning change?
The book is excellent.
Yes! This sentence does not mean the same thing as the first sentence. That
means the phrase “that I borrowed from you” is essential. We do NOT need
commas.
Tip: Phrases that
begin with “that”
are ALWAYS
essential
12. Rule #5: Use a comma to separate three
or more words, phrases, or clauses in a
series
Always use commas to separate items in a series as in these examples:
The Constitution establishes the legislative, judicial, and executive
branches of the government.
The prosecutor argued that the defendant, who was at the scene of the
crime, had a strong revenge motive, and had access to the murder
weapon, was guilty of homicide.
Technically, the final comma before “and” in any series is optional.
However, it’s often helpful to use it to avoid confusion for readers.
13. Rule #6: Use a comma to separate two or
more coordinate adjectives that describe
the same noun
When using two or more adjectives to describe the same now without a
connecting word such as “and,” use a comma to separate them.
Jane was a happy, healthy baby.
The relentless, powerful, hot sun beat down on us all afternoon.
But be careful: If the adjectives are not coordinate and do not describe the same
noun, do not use commas to separate them.
She wore a grey wool shawl.
Here, grey is describing wool and wool is describing shawl. They are not
coordinate and do not need a comma.
14. Rule #7: Use commas to separate
geographical info, dates, addresses and
titles
Commas are used to separate geographical names, address information,
dates, and titles.
Birmingham, Alabama, gets its name from Birmingham, England.
July 22, 1959, was a momentous day in his life.
Who lives at 1600 Pennsylvania Avenue, Washington, DC?
Rachel B. Lake, MD, will be the principal speaker.
When you only have the name of the month and the year, however, no comma is
needed.
The average temperatures for July 1998 are the highest on record for that
month.
15. Rule #8: Use a comma to separate a
signal phrase from a quotation
A comma should be used to separate a signal phrase from a quotation
no matter where it appears in the sentence.
John said without emotion, "I'll see you tomorrow."
"I was able," she answered, "to complete the assignment."
"Workers of the world, unite,” Marx wrote.
Quotations in your writing should always have a signal phrase.
16. Let’s Review!
Comma Rules
We’ve covered 8 major rules for using
commas in your writing, and by
learning and applying these rules,
you’ll show a much improved use of
punctuation and avoid common
errors that will hurt your grade.
Review these rules often as you write
and use practice activities to
reinforce the skills.
1. Use a comma to connect two
independent clauses with a FANBOYS
2. Use a comma when a dependent
clause precedes and independent
clause
3. Use a comma to separate non-essential
elements
4. Do NOT use a comma to separate
essential elements
5. Use a comma to separate three or
more items of a series
6. Use a comma to separate two or more
adjectives that describe the same noun
7. Use a comma to separate
geographical info, dates, titles, and
address info
8. Use a comma to separate a signal
phrase from a quotation
17. Additional Resources
To learn more about sentence boundary errors:
See section 39 (pages 306 -322) in your Little, Brown Brief
See the Purdue Online Writing Lab resource on clauses. Click here to
visit the page (opens in new window).
<http://owl.english.purdue.edu/owl/resource/607/02/>
Notas del editor
Hello.Welcome to the grammar module on sentence boundaries. This module will define errors with boundaries and help you correct common sentence issues such as fused sentences and comma splices.
Let’s begin by reviewing the basic structure of a sentence.
A sentence, very simply is made up of two primary elements: a subject and a verb. The subject of any sentence is the person or thing doing the action of the sentence. The verb is that action. Complete sentences should only have one main subject and one main verb. Being able to identify these elements is the first step to avoiding errors with sentence boundaries and fragments.
We’ve also discussed errors with sentence boundaries and how to avoid and correct common errors such as comma splices and fused sentences. Remember to review how to correct these errors in your writing.
The rules we’ll cover in this lesson are designed to help you control comma usage in your writing. You’ll need to refer to them often to avoid errors.
The first rule is a review. You should use a comma before a coordinating conjunction when it connects to independent clauses as in this example. But be careful, remember that both sides of the FANBOYS must be independent for the comma to be necessary. If both sides cannot stand alone as sentences, then a comma is not needed. A helpful way to remember this is with an equation. IC + FB + IC = Comma
Rule #2 comes back to dependent clauses. When we learned about clauses, we learned that dependent clauses are those that require an independent clause to be complete. They always have subordinating conjunctions such as because, although, since, and if – among others. Our second comma rule tells us that when a dependent clause comes before an independent clause in a sentence, you should use a comma to separate them, as we see here. In this example, we know the first clauses is dependent because of the word because. And since it comes before the independent clause, we use a comma after morning, the word that ends the dependent clause.
Be careful with Rule #2. You only use a comma between dependent and independent clauses when the dependent clause comes first. If the independent clause comes first, no comma is needed, as we see here. When we flipped the construction of this sentence, we put the independent clause first. Because of that, no comma is needed here.
Rule #3 deals with non-essential elements. Non-essential elements are parts of the sentence that are additional information. They might be introductory elements or modifying information. You might also know these elements as “interrupters.” In this sentence, the phrase “which happens to be my birthday” is a non-essential element. It provides the reader with more information but it is not required for the sentence to make sense. When you have non-essential elements, use a comma (or commas) to separate them from the main part of the sentence. Let’s look a little more in-depth at non-essential elements.
To determine whether an element is non-essential, take it out of the sentence. If the sentence still makes sense and you haven’t changed its meaning, the element isn’t needed. Both of these examples convey the same idea. By removing the non-essential element, we haven’t screwed anything up. It’s important to remember that non-essential elements can appear anywhere in the sentence. But no matter where they appear, a comma is needed to separate them. Now, one last thing on rule #3.
Sometimes phrases that convey additional information are needed for the sentence to make sense. These are essential elements, and you should not use a comma to separate them from the main part of the sentence. You might wonder if the phrase “that I borrowed” from you needs commas around it in this example. Let’s test it. If we take the phrase out of the sentence, does the meaning change? It does. And since it does, we would not use commas to separate it from the rest of the sentence. One helpful tip: phrases that begin with that are always essential to the meaning of the sentence.
Rule #5: Always use commas to separate items in a series as we see in these examples. These items might be single words, phrases, or clauses. The final comma before the “and” in a series is technically optional, but it using it often helps avoid confusion for readers.
Rule #6. When you have two or more adjectives that describe the same noun, separate them with a comma, as in these examples. But, when the adjectives are not describing the same noun, do not use a comma. Here, grey describes wool, not shawl, while wool describes shawl. For this sentence, no comma is needed.
Rule #7: Use commas to separate geographical info, dates, addresses, and titles as in these examples. But, when you only use the month and year, you do not need a comma between them.
Rule #8. Use a comma to separate a quotation from a signal phrase. Signal phrases can appear in any part of the sentence. No matter where they are, they should always be separated with a comma.
The eight major rules we’ve covered here regarding commas will help you control your writing and avoid the types of mistakes that cause confusion and will hurt your grade. You’ll need to review them often and practice to apply what you’ve learned.
Finally, use these additional resources to learn more about commas or to review as we build on this knowledge in upcoming modules.