run-on sentences

A run-on sentence is one that contains two or more independent clauses (simple sentences) that are not properly connected.

Types of run-on

There are two main types of run-on: the fused run-on and the comma splice. A few sources identify a third kind of run-on, sometimes called the and run-on.

Fused run-on

In a fused run-on, the clauses are run together without anything to connect them:

• The power went out last night the lights were off all over the city.

Comma splice

In a comma splice, the clauses are joined incorrectly with a comma:

• The power went out last night, the lights were off all over the city.

(The use of a comma alone between independent clauses is correct only if the clauses are short and parallel: John saved, Tara spent.)

The comma splice is especially common when a conjunctive adverb (however, in addition, therefore, etc.) appears between the two clauses:

• The power went out last night, therefore, the lights were off all over the city.

And run-on

In an and run-on, the clauses are incorrectly joined by one of the coordinating conjunctions alone, without a comma:

• The power went out last night and [or so] the lights were off all over the city.

Correcting a run-on

There are several ways to correct a run-on sentence. You can try one of the following solutions.

Solution 1

Separate the two clauses with a period:

• The power went out last night. The lights were off all over the city.

Solution 2

Join the two clauses with a comma and a coordinating conjunction (for, and, nor, but, or, yet, or so):

• The power went out last night, and the lights were off all over the city.

Solution 3

Join the two clauses with a semicolon (and a conjunctive adverb if it improves the flow of ideas):

• The power went out last night; the lights were off all over the city.
• The power went out last night; as a result, the lights were off all over the city.

Solution 4

Make one of the clauses into a dependent word group (such as a dependent clause or a phrase):

• When the power went out last night, the lights were off all over the city.
• During last night’s power outage, the lights were off all over the city.