What Makes a Run-On Sentence?

Wednesday, January 103 min read

Short clauses can be boring or feel choppy, but run-on sentences are clumsy — so what’s a writer to do? Use these simple tips to add variety to your sentence structure while avoiding run-on sentences.

How to Identify a Run-On Sentence

A run-on sentence occurs when two independent clauses are combined into one sentence without proper punctuation or a conjunction. If each clause can stand alone and still make sense, it is probably a run-on sentence.

In general, there are three types of run-on sentences. (Note: There are additional grammatical issues at play in these examples, but we’re only looking at the run-on sentence construction.)

A fused sentence joins two clauses without any punctuation or conjunction.

Example: It rained all day the road began to flood.

A comma splice joins two clauses with a comma, but without a conjunction.

Example: It rained all day, the road began to flood.

A polysyndeton is a chain of clauses joined together with too many conjunctions.

Example: It rained all day and the road began to flood and I was late getting home.

This final example might be closest to how people speak in casual conversation, but when it’s written out, the run-on sentence can be overwhelming.

How to Correct a Run-On Sentence

When you spot a run-on sentence, the easiest ways to correct it are to either split it up into multiple sentences, or to insert punctuation to correct the errors that created the run-on sentence.

Creating multiple sentences out of the one run-on sentence works best when the clauses are loosely related.

Example:

Incorrect: It rained all day we decided to order takeout for dinner.

Correct: It rained all day. We decided to order takeout for dinner.

When the clauses have a closer relation, you can insert a semicolon to separate the ideas, but keep them within the same sentence.

Example:

Incorrect: It rained all day the road began to flood.

Correct: It rained all day; the road began to flood.

Correcting a run-on sentence by inserting a comma and a conjunction also works for many types of situations. It creates a nice flow between the clauses.  

When using a comma to separate clauses, adding a coordinating conjunction (“for,” “and,” “nor,” “but,” “or,” “yet,” or “so”) to separate your ideas will avoid a comma splice.

Example:

Incorrect: It rained all day I was late getting home.

Incorrect: It rained all day, I was late getting home.

Correct: It rained all day, so I was late getting home.

Correct: It rained all day, and I was late getting home.

A subordinating conjunction (“because,” “before,” “now,” “though,” “until,” “while,” etc.) might require a comma or a reordering of the sentence, depending on the conjunction and whether it’s a dependent clause.

Example:

Correct: I was late getting home because it rained all day.

Correct: Since it rained all day, I was late getting home.

Is It Ever Okay to Use a Run-On Sentence?

Using a run-on sentence is almost always incorrect unless used for stylistic reasons, such as in a book, poem, or other forms of creative writing. There are many examples of rhetorical run-on sentences, but one of the most famous is the opening line of Charles Dickens’ A Tale of Two Cities:

“It was the best of times, it was the worst of times, it was the age of wisdom, it was the age of foolishness, it was the epoch of belief, it was the epoch of incredulity, it was the season of Light, it was the season of Darkness, it was the spring of hope, it was the winter of despair, we had everything before us, we had nothing before us, we were all going direct to Heaven, we were all going direct the other way — in short, the period was so far like the present period, that some of its noisiest authorities insisted on its being received, for good or for evil, in the superlative degree of comparison only.”

If you’re writing for style, feel free to let loose a little bit — but unless you’re a descendant of Dickens, don’t attempt a more than 100-word run-on sentence.

Featured image credit: enigma_images/ iStock

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