Run-On Sentences and Comma Splices

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To learn more about run-on sentences and comma splices, check out our slideshow, Avoiding Run-on Sentences.

Definition

A run-on sentence  is composed of two independent clauses that can stand entirely on their own but are joined without a conjunction or correct punctuation. It is important to realize that the length of a sentence really has nothing to do with whether a sentence is a run-on or not; being a run-on is a structural flaw that can plague even a very short sentence. An extremely long sentence, on the other hand, might be a “run-off-at-the-mouth” sentence, but it can be otherwise sound, structurally.

Below, you will find a 239-word sentence that is a perfectly fine sentence (structurally):

Knowing that millions of people around the world would be watching in person and on television and expecting great things from him — at least one more gold medal for America, if not another world record — during this, his fourth and surely his last appearance in the World Olympics, and realizing that his legs could no longer carry him down the runway with the same blazing speed and confidence in making a huge, eye-popping leap that they were capable of a few years ago when he set world records in the 100-meter dash and in the 400-meter relay and won a silver medal in the long jump, the renowned sprinter and track-and-field personality Carl Lewis, who had known pressure from fans and media before but never, even as a professional runner, this kind of pressure, made only a few appearances in races during the few months before the Summer Olympics in Atlanta, Georgia, partly because he was afraid of raising expectations even higher, and partly because he did not want to be distracted by interviews and adoring fans who would follow him into stores and restaurants demanding autographs and photo-opportunities, but mostly because he wanted to conserve his energies and concentrate, like a martial arts expert, on the job at hand: winning his favorite competition, the long jump, and bringing home another Gold Medal for the United States, the most fitting conclusion to his brilliant career in track and field.

 

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Correcting Run-On Sentences

Consider the following example:

  • The sun is high, put on some sunblock.

In the above sentence, two independent clauses are joined together with a comma. When two independent clauses are connected by only a comma, they constitute a run-on sentence that is called a comma splice. A comma alone is insufficient to join two heavy-weights such as independent clauses. To correct the sentence, you would need to employ one of the strategies listed below.

There are four ways to join or separate two, independent clauses successfully:

1. Use a period: Separate each independent clause with a period.

  • The sun is high. Put on some sunblock.

2. Use a comma with a coordinating conjunction: Join each independent clause with a comma followed by a coordinating conjunction (and, but, for, nor, yet, so, or)

  • The sun is high, so put on some sunblock.

3. Use a semicolon: Join each independent clause with a semicolon when the two ideas are closely related.

  • The sun is high; put on some sunblock.

4. Use a semicolon with a conjunctive adverb: Join each independent clause with a semicolon, followed by a conjunctive adverb (however, nevertheless, otherwise, moreover, etc.) and a comma.

  • The sun is high; moreover, you should put on some sunblock.

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More Examples of Run-On Sentences and Their Corrections

Sentence

Explanation

Run-On Sentence

The class was almost finished and the students were restless. This is a run-on because it combines two, independent clauses with a coordinating conjunction. A coordinating conjunction alone is insufficient to join the two clauses.

Correction

The class was almost finished, and the students were restless. Inserting a comma before the coordinating conjunction allows you join the two, independent clauses together successfully.

Sentence

Explanation

Run-On Sentence

The water was choppy the kayak nearly capsized. This is a run-on because it combines two, independent clauses without sufficient punctuation.

Correction

The water was choppy; the kayak nearly capsized. Inserting a semicolon between the two clauses corrects the error. Because the clauses are closely related, a semicolon works well.

Review, also, the section which describes punctuation between two independent clauses.

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Exercises

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