In this lesson,
you'll learn about sentence boundaries and the way(s) that run-ons
and comma splices are created. You'll also learn how to identify and
eliminate run-ons and comma splices in your writing.
The Importance
of Sentence Boundaries
One of the most
important principles of writing in English is to mark the boundaries
of each sentence. That is, the beginning of a sentence must have a
capital letter, and the end of a sentence must have an appropriate
form of end punctuation, such as a period.
Very few writers
have trouble indicating the beginning of a sentence because they have
been trained from elementary school on to use a capital letter to
show the start of a new thought. However, many writers experience
difficulties indicating the end of a sentence: Either they neglect
to put punctuation at the end of a sentence, creating a "run-on";
or they use a form of punctuation, such as a comma by itself, that
doesn't truly signal the end of a sentence, creating a "comma splice."
Run-ons
A run-on,
or fused sentence, occurs when two independent clauses are connected
— or "run together" — without any form of punctuation between
them.
We had a fun
day at the lake we went swimming and fishing.
This sentence
contains two independent clauses — we had a fun day at the
lake and we went swimming and fishing. However, without
an appropriate mark of punctuation between them, the independent clauses
run together; as a result, readers don't know where the first thought
ends and the second one begins. This "running together" causes two
separate ideas to be melded into one, which is confusing to the reader.
Comma Splices
Similarly, a
comma splice occurs when only a comma separates two independent
clauses. A comma by itself isn't an appropriate mark of punctuation
to signal the end of a sentence.
We had a
fun day at the lake, we went swimming and fishing.
This sentence
contains the same two independent clauses, and these independent clauses
seem to be separated by a comma in such a way that readers
can tell where the first thought ends and the second one begins. However,
according to the principles of English punctuation, this comma is
"splicing" or joining the two independent clauses together, rather
than separating them into individual sentences, as a period would.
Therefore, the comma by itself can't be used to indicate the end of
a sentence.
Eliminating
Run-Ons and Comma Splices
Once you've identified
a run-on or a comma splice, there are several possible ways for you
to eliminate them. The method you choose depends upon the meaning
you're trying to convey.
(1) Place a period
or semicolon between the two independent clauses.
We had a fun
day at the lake. We went swimming and fishing.
We had a fun
day at the lake; we went swimming and fishing.
Although the
period and semi-colon function in the same way, indicating the end
of an independent clause, they convey slightly different meanings
to readers. A period tells readers that there's a complete
separation, or a "full stop," between the two adjoining independent
clauses. A semi-colon, however, tells readers that the two
independent clauses are closely related, without indicating for readers
the specific nature of that relationship (such as one of addition,
contrast, choice, cause/effect, etc.). It can be helpful to remember
that a semi-colon is a visual means of connecting the ideas in two
sentences. It is "heard" in reading aloud like a "full stop" of a
period.
(2) Create a
compound sentence by joining the two independent clauses with a comma
and a coordinating conjunction:
We had a
fun day at the lake, for we went swimming and fishing.
Using a comma
and a coordinating conjunction, like a semi-colon, tells readers that
the two independent clauses are closely related; and yet, the choice
of coordinating conjunction tells readers the precise nature of that
relationship. The relationship expressed by each of the coordinating
conjunctions (remember the keyword "fanboys") is:
For:
cause/effect And: addition
Nor: choice
But: contrast Or: choice
Yet: contrast
So: result
(3) Create a
compound sentence by joining the two independent clauses with a semicolon,
a conjunctive adverb, and a comma:
We had a fun
day at the lake; indeed, we went swimming and fishing.
Using a semi-colon
along with a conjunctive adverb and a comma also indicates that a
relationship exists between the two independent clauses; and, in this
case, the conjunctive adverb indeed tells readers that the specific
nature of that relationship is one of emphasis. Further, the comma
following the conjunctive adverb indicates to readers that the word
indeed is introductory, coming before the subject and the predicate.
Some common conjunctive
adverbs, as well as their meaning, are as follows:
Consequently:
result Furthermore: addition However: contrast Otherwise: choice Therefore: result
(4) Create a
complex sentence by adding a subordinate word at the beginning of
one of the independent clauses and joining the two independent clauses:
Because we
went swimming and fishing, we had a fun day at the lake.
(dependent clause is because we went swimming and fishing)
We had a fun
day at the lake when we went swimming and fishing.
(dependent clause is when we went swimming and fishing)
Adding a subordinate,
or "dependent," word at the beginning of one of the independent clauses
changes the nature of that clause, making it dependent; and, because
this clause is now dependent, it must be connected to an existing
independent clause. When the dependent clause is placed before the
independent clause, it must be separated from the independent clause
with a comma; however, when the dependent clause is placed after the
independent clause, there's no need for a comma.
Note:
A fragment is created if a period rather than a comma punctuates the
dependent clause.
Exercise
1: In the paragraph below, examine the following sentences for
errors in sentence boundaries. Label each sentence as either "complete"
or containing a "run-on" or a "comma splice."
1. I have a specific routine that helps me wake up in the morning.
Complete
Run-on
Comma Splice
2. After my alarm sounds, I spend a few minutes stretching, once I leave
my bed, I go to the kitchen to make coffee.
Complete
Run-on
Comma Splice
3. While it's brewing,
I grab my local newspaper from the doorstep I scan the headlines.
Complete
Run-on
Comma Splice>
4. Then, with a cup of coffee in my hand and the newspaper on my
lap, I turn on a national television program, I want to hear about
what's going on in the world.
Complete
Run-on
Comma Splice
5. Only after I've done this, and
finished my cup of coffee, do I feel ready to begin tackling the
day.
Complete
Run-on
Comma Splice
Summary
Sentences need
to have specific boundaries, such as a capital letter at the beginning
and an appropriate mark of punctuation at the end. When no punctuation
is used to indicate the end of a sentence, a "run-on" occurs; when
the sole mark of punctuation used to indicate the end of a sentence
is a comma, a "comma splice" occurs. There are several methods for
eliminating these sentence boundary errors: using a period or semi-colon;
using a comma and a coordinating conjunction; using a semi-colon,
conjunctive adverb, and comma; and using a subordinate word. As writers,
it's important to be able to recognize errors in sentence boundaries
because they make it difficult for readers to understand what you're
trying to say. Eliminating errors in sentence boundaries is essential
for readers to grasp your meaning.
