Run-on Sentences

Run-on sentences occur when two or more complete sentences (two or more units of subject-verb-words to complete the thought) are incorrectly joined. Note that if the two sentences are inappropriately joined with only a comma, the error is also called a comma splice.

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Examples: each full sentence is indicated in a different color and enclosed in brackets

  • [Choosing a topic for a paper can be the hardest part] but [it gets a lot easier after that].
  • [Sometimes, books do not have the most up-to-date information], [it is a good idea then to look for articles in specialized periodicals].

There are three possible, correct ways to deal with two complete sentences that you may want to link together:

  1. add a comma + a linking word that indicates the idea relationship between the sentences (e.g., “and,” “but,” “or,” etc.)
  2. add a semi-colon between the end of the first sentence and the start of the second sentence
  3. decide not to join the sentences, and separate them into two distinct sentences

The sentences in the example above are run-on sentences because they don’t have adequate linkage. They may be corrected in the following ways:

Sentence 1

  • Choosing a topic for a paper can be the hardest part, but it gets a lot easier after that. [add a comma before the linking word, as you need both the comma and the linking word]
  • Choosing a topic for a paper can be the hardest part; it gets a lot easier after that. [semi-colon linking the sentences]
  • Choosing a topic for a paper can be the hardest part.  It gets a lot easier after that. [two separate, complete sentences]

Sentence 2

  • Sometimes, books do not have the most up-to-date information, so it is a good idea then to look for articles in specialized periodicals. [add a linking word to the comma]
  • Sometimes, books do not have the most up-to-date information; it is a good idea then to look for articles in specialized periodicals. [semi-colon linking the sentences]
  • Sometimes, books do not have the most up-to-date information.  It is a good idea then to look for articles in specialized periodicals. [two separate, complete sentences]

 

Note: A run-on sentence is not merely a sentence that just goes on and on. A run-on sentence is a sentence that is not correctly punctuated. Not every long sentence is a run-on sentence. For example, look at this quote from The Great Gastby:

Its vanished trees, the trees that had made way for Gatsby’s house, had once pandered in whispers to the last and greatest of all human dreams; for a transitory enchanted moment man must have held his breath in the presence of this continent, compelled into an aesthetic contemplation he neither understood nor desired, face to face for the last time in history with something commensurate to his capacity for wonder.

If you look at the punctuation, you’ll see that this quote is a single sentence. F. Scott Fitzgerald used commas and semicolons is such a way that, despite its great length, the sentence is grammatically sound. Length is no guarantee of a run-on sentence.

Common Causes of Run-Ons

We often write run-on sentences because we sense that the sentences involved are closely related and dividing them with a period just doesn’t seem needed. We may also write them because the parts seem too short to need any special punctuation, as in “She loves skiing but he doesn’t.” However, “She loves skiing” and “he doesn’t” are both complete sentences, so they need to be linked by a both comma and a linking word, and not just a linking word by itself in this case.

Special Cases with Linking Words

Some linking words present special cases:  however, therefore, furthermore, additionally.

When you use these words in a sentence, you usually use a comma after them, e.g.:

  • However, we decided to follow the GPS instead of his directions, and we did end up getting lost.
  • Additionally, I like plums, mangoes, and bananas.
  • Therefore, we concluded that eating at fancy restaurants was not feasible with our budget.

When you use these linking words to start the second sentence of two linked sentences, you need to use a semi-colon or a period to link the two complete sentences, e.g.:

  • We asked a farmer at the farm stand how to get to our B&B; however, we decided to follow the GPS instead of his directions, and we did end up getting lost.
  • I like oranges and apples; additionally, I like plums, mangoes, and bananas.
  • Our dinner out last night ended up costing almost ninety-four dollars; therefore, we concluded that eating at fancy restaurants was not feasible within our budget.

Practice

Identify the run-on sentences in the following paragraph. Type a corrected version of the paragraph in the text frame below:

I had the craziest dream the other night. My cousin Jacob and I were on the run from the law. Apparently we were wizards and the law was cracking down on magic. So, we obviously had to go into hiding but I lost track of Jacob and then I got picked up by a cop. But I was able to convince him that the government was corrupt and that he should take me to my escape boat.