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Run-on Sentences

Definition: A run-on sentence is a grammatically incorrect sentence that has two or more complete sentences connected without any punctuation.

Identifying Run-on Sentences:

Look for more than one independent clause in a sentence. If there is no punctuation joining them together, then this is likely a run-on sentence. Another trick is to look for two subjects (which can include a subject and its pronoun) in the same sentence. If they are not separated with a punctuation mark, then it is likely a run-on sentence.

  • She touched the stove it was hot. (Notice that there are two independent clauses with no punctuation. This is a run-on sentence.)
  • She touched the stove. It was hot. (The run-on was fixed by interesting the proper punctuation.)

Sometimes run-on sentences are turned into comma splices. A comma splice is another grammatical error. It comes from separating two independent clauses with a single comma. So, you cannot fix a run-on sentence with a single comma. 

Here are the four main ways to fix run-on sentences:

1. Use a semi-colon to separate the clauses.

Run-on: I have three cars my favorite is the convertible.

Corrected: I have three cars. My favorite is the convertible.

2. Break it into two separate sentences.

Run-on: Charlotte is happy she is always smiling.

Corrected: Charlotte is happy. She is always smiling.

3. Add a comma and a subordinating conjunction

Examples of subordinating conjunctions include: as, even though, because, since, while, until, although, before, after, unless, if, when. 

Run-on: Charlie was tired he went to bed.

Corrected: Since Charlie was tired, he went to bed.

4. Add a comma and a coordinating conjunction

Examples of coordinating conjunctions include: but, or, and, for, nor, yet, so.

Run-on: Anna studied hard she still failed the test.

Corrected: Anna studied hard, but she still failed the test.

Related:  Now learn about sentence fragments here.


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By Patrice Riley

Patrice Riley is the pen name of Dr. Deborah Riley. She is a retired English professor that enjoys grammar, literature, and all things writing.

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