A run-on sentence joins at least two independent clauses without a conjunction or adequate punctuation. An independent clause has a subject and a verb, and could essentially be a sentence by itself. For example one might write, “I like ice cream it tastes really good.” There are essentially two independent clauses here, which could be written as two separate sentences. “I like ice cream. It tastes really good."
One of the most common types of run-on sentences is called a comma splice. It occurs when a comma separates two independent clauses. Thus we would have “I like ice cream, it tastes really good.” There are a few ways to address a comma splice, and eliminate the run-on. If you really feel the two independent clauses need to exist in the same sentence, you can substitute a semi-colon for the comma. Alternately, you could separate the two clauses by using a conjunction. In this example you would use the word “and”: “I like ice cream and it tastes really good.”
Another way of attacking the run-on sentence is to replace the comma with a subordinating conjunction. This essentially turns one of the clauses into a dependent clause. In this case we could use “because.” Our sentence would become, “I like ice cream because it tastes really good. The word "because" makes the second independent clause dependent. It can no longer stand on its own. “Because it tastes really good,” is not a sentence.
Depending upon the type of sentence, one could examine other subordinating conjunctions that would fix a run-on sentence. These include: after, although, because, as, if, while, even though, since, until and when. Subordinating conjunctions keep two thoughts in a sentence entwined together, which is often what the person perpetuating the sentence is striving for.
To help eliminate the run-on sentence from you written work, you can run a little check on each sentence. Ask yourself the following:
- Does my sentence have two separate subjects and two separate (not helping) verbs?
- Does my sentence have two independent clauses joined by a comma?
A run-on sentence may also be applied to sentences that tend to go too far. For example, one doesn’t want to keep adding conjunctions and making a sentence longer. “I like ice cream because it tastes good and I really think it improves my mood and I get it free when I go roller skating." This type of sentence is a run-on because it has used too many conjunctions. Separating independent clauses serves a point for the reader. It helps make each point clear. Too many “ands" in this case obscure the point and the reader gets lost.
In general, you want to avoid this type of run-on sentence by varying sentence length. You could write: “I like ice cream because it tastes good and improves my mood. Also, I get it free when I go roller skating.” Try to keep each thought concise, or cut down on the sentence in other ways. Instead of “I like ice cream, I like roller skating, and I like eating to improve my mood, consider, “I like ice cream, roller skating, and eating to improve my mood.” Try to join no more than two independent clauses with commas and conjunctions together to avoid the run-on sentence of this type. Also avoid repeating the same subject and verb to simplify the sentence.