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Fragments, comma splices, and run-ons

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Sentence fragments, comma splices, and run-on sentences are three of the most common writing errors. Here are some tips on recognizing and correcting these mistakes.

Sentence fragmentComma spliceRun-on sentenceTry it out

Sentence fragment (Incomplete sentence)

A sentence must (1) contain both a subject and a verb and (2) express a complete thought.

For example, the sentence “Rob plays hockey for Queen’s” has a subject (“Rob”) and a verb (“plays”) and expresses a complete thought.

But the following examples contain fragments:

Rob enjoyed his time at Queen’s. Playing university hockey. (The second sentence does not have a subject and verb, nor does it express a complete thought on its own.)

Rob enjoyed his time at Queen’s. When he played hockey. (The second sentence has a subject and verb but is incomplete; the reader wonders, “What about when he played hockey?”)

Comma splice

A comma splice occurs when you link two complete sentences together with a comma:

The war had no single cause, there were many contributing factors.

This error can be corrected in several ways: by putting a period after “cause” and creating two sentences; by putting a semicolon after “cause”; or by completely rewording the sentence (e.g., A number of factors, not merely one, caused the war).

Run-on sentence

A run-on sentence occurs when you link two complete sentences together with no punctuation. It is especially common when you are using a connecting word like “however”:

There are various types of feminism however they share some common features.

The above sentence actually contains two smaller ones (you could put a period after “feminism”), but they have been stuck together, creating a run-on.

As with the comma splice, you have several options for correction: putting a period before “however” and a comma after; putting a semicolon before “however” and a comma after; or rewording (e.g., Although there are various types of feminism, they share some common features).

Try it out

For practice, try correcting the following paragraph:

Romeo and Juliet is one of Shakespeare’s most popular plays. Romeo encounters Juliet at a party, they immediately fall in love but must keep their love a secret. Given that their families are enemies. They hope to defy their families’ feud however, when Juliet’s relative is killed, Romeo is forced to flee. Seeking refuge with his friend Friar Lawrence. Romeo’s and Juliet’s lives end in tragedy, misunderstanding and despair lead them both to suicide.