RUN-ON SENTENCES
Run-on sentences are one of the most common writing errors. Many students have trouble locating and fixing run-on sentences. This handout will show you how to identify and fix run-on sentences in your essays.
Run-on sentences have two complete sentences that lack correct punctuation. Run-on sentences can be confusing to the reader because they do not show where one idea ends and the next idea begins. There are two types of run-on sentences: the fused sentence and the comma splice. A fused sentence is a sentence that has two or more complete sentences without the correct punctuation between them. A comma splice is two or more complete sentences held together by only a comma.
Example of a fused sentence:
Bob went to the store he bought some apples.
Example of a comma splice:
Bob went to the store, he bought some apples.
“Bob went to the store” and “He bought some apples” are complete sentences. A complete sentence is called an independent clause. An independent clause contains a subject and a predicate, which is the portion of the sentence that contains the verb. Both of these sentences can be fixed by using a period, semicolon, colon, coordinating conjunction, subordinating conjunction, or a conjunctive adverb or transitional phrase.
∞ Adding a period makes two complete sentences:
Bob went to the store. He bought some apples.
A period is used when a sentence is complete. Any independent clause can be ended with a period.

[Separating sentences with a period is the easiest way to correct fused sentences and comma splices. However, it can lead to incoherent paragraphs. Combining sentences and using transitional phrases will help remedy an incoherent sentence. Please see the
Transitional Phrases I and II handouts for additional information.]

∞ Adding a semicolon or a colon makes one complete sentence:
Bob went to the store; he bought some apples.
A semicolon should only be used when the ideas are closely related. The sentences should logically “flow” together. In cases where it is unclear whether or not the ideas are closely related, it is probably safer to not use the semicolon.
∞ Adding a comma and coordinating conjunction will make one complete sentence:
Bob went to the store, and he bought some apples.
A coordinating conjunction gives equal weight to both sentences. In other words, each independent clause is equally important. The most common coordinating conjunctions for, and, nor, but, or, yet, and so can be easily recalled from the acronym FANBOYS.
Coordinating Conjunctions
For And Nor But Or Yet So = FANBOYS
Use the FANBOYS formula to combine independent clauses:
Subject + Predicate, {FANBOYS} Subject + Predicate

∞ Adding a subordinating conjunction:
After Bob went to the store, he bought some apples.
Bob bought some apples after he went to the store.
Adding a subordinating conjunction to one of the two independent clauses creates an independent clause and a dependent clause. As stated earlier, an independent clause is a complete sentence that contains a subject and a predicate. A dependant clause contains a subject, a verb, and a subordinating conjunction.

Unlike a coordinating conjunction, a subordinating conjunction creates a sentence in which the ideas are given an unequal weight because one sentence is dependent on another. The dependent clause requires an independent clause. Without the independent clause, the dependant clause is a fragment.
Common Subordinating Conjunctions
After
Although
As
Before

Because
If
Since
That

Until
When
Whenever
While

Use these formulas to use subordinating conjunctions:
{Subordinating Conjunction} Subject + Predicate, Subject + Predicate
Subject + Predicate {Subordinating Conjunction} Subject + Predicate
∞ Adding a semicolon, a conjunctive adverb or transitional phrase, and a comma makes a complete sentence:
I have to study; therefore, I cannot go swimming this afternoon.
A