18.2: Run-ons

Sometimes, a professor will tell a student that they have written a run-on sentence, and the student takes that to mean they have written a sentence that is too long. While in theory a sentence can be of any length, the professor in this instance is not referring to its length. A run-on sentence (also sometimes called a fused sentence) occurs when you connect two complete clauses or independent clauses without proper punctuation or a coordinating conjunction. Often, run-on sentences are easy to spot because of their length, but this is not always the case: for instance, you might come across two short sentences put together without connective punctuation.

Example Run-on: I used to wonder what was wrong with the way I write I write just the way I talk.

These two sentences are fairly common kinds of run-ons in that, as you can see when reading through them, there is no kind of separation between the first and second independent clauses that comprise each sentence. In the first sentence, the first independent clause runs from “I” to the end of the first “I write,” and the second clause runs from the second “I write” to the end of the sentence. What makes the second clause easy to spot is that “I” is a subject pronoun, meaning that it functions only as a subject for verbs—and, conveniently for English-speakers and -readers, our sentences’ subjects tend to appear near the beginnings of sentences. (What makes it even easier to spot is when we read it out loud; the sentence may say the person writes the way they talk, but reading it aloud would show us in pretty short order that no one actually does talk like that.)

Example Run-on: Then I took my first college English class I soon learned that writing and talking are different things.

This sentence, as you can see, is similar to the first example, but with this difference: we see “. . . took my first English class I soon learned . . .,” and we note that “class” is the direct object of the verb “took.” This means that, as far as the nature of independent clauses is concerned, “class” marks the end of that clause. We can confirm that by looking at the next word in the sentence, the subject pronoun “I.” Another basic rule of English syntax is that, except for proper nouns, nouns in English do not appear next to each other in the same sentence unless they are items in a list. That rule makes it doubly certain that we can place a period, or a semicolon, or a comma and an appropriate coordinating conjunction between “class” and “I.”

Example Run-on: My first essay in English 101 was difficult for me to write fortunately I got help with it.

The third sentence is perhaps a bit trickier to identify as a run-on because the first independent clause (from “My” to “write”) consists of a verb, a complement, a prepositional phrase, and an infinitive. Once again, though, we see the subject pronoun “I” and, remembering our rule, we know that that signals that we are in the vicinity of another independent clause. From there, our only real job is to determine whether “fortunately” belongs to the first or the second independent clause, and then punctuate appropriately.

You should be able to apply these rules as you work through and correct the sentences below.

See this page for help understanding run-on sentences and how to fix them. See this lesson from Khan academy for more practice with run-ons.