The comma-splice and run-on sentence (and the fused sentence, as a variant is called) are all examples of the problem in which two or more sentences are improperly joined. In the typical comma-splice sentence, two sentences are joined by a comma without an intervening coordinating conjunction (and, or, nor, but, yet). Technically, the run-on sentence is a sentence that goes on and on and needs to be broken up; it’s likely to be a comma splice as well. A fused sentence is two complete sentence just jammed together without any punctuation and without any conjunction.
We write comma-splice and run-on sentences because we sense that the sentences involved are closely related—a full-stop period just doesn’t seem right. Actually, the semicolon is the right choice in these situations (although it’s easy to go semicolon crazy when you first start using them). Below are some examples of this type of problem and some possible revisions.
replace the comma with a semicolon
Problem: Sometimes, books do not have the most complete information, it is a good idea then to look for articles in specialized periodicals.
Revision: Sometimes, books do not have the most complete information; it is a good idea then to look for articles in specialized periodicals.
Break the sentence into two separate sentences
Problem: Most of the hours I’ve earned toward my associate’s degree do not transfer, however, I do have at least some hours the University will accept.
Revision: Most of the hours I’ve earned toward my associate’s degree do not transfer. However, I do have at least some hours the University will accept.
Sometimes a full colon is appropriate
Problem: The opposite is true of stronger types of stainless steel, they tend to be more susceptible to rust.
Revision: The opposite is true of stronger types of stainless steel: they tend to be more susceptible to rust.
add a conjunction
Problem: Some people were highly educated professionals, others were from small villages in underdeveloped countries.
Revision: Some people were highly educated professionals, while others were from small villages in underdeveloped countries.
edit for clarity and add a conjunction
Problem: This report presents the data we found concerning the cost of the water treatment project, then it presents comparative data from other similar projects.
Revision: This report first presents the data we found concerning the cost of the water treatment project and then comparative data from other similar projects.
simplify: use a comma and a preposition
Problem: Most of this firm’s contracts have been with major metropolitan hospitals, included among them is Memorial East in Luckenbach.
Revision: Most of this firm’s contracts have been with major metropolitan hospitals, including Memorial East in Luckenbach.
There are numerous online resources offering grammar and punctuation practice. The Purdue OWL website is a great place to start if you want more grammar practice.
