Run-on sentences

A run-on sentence is not simply a sentence that is too long. Rather, it is a sentence in which two or more independent clauses are fused together without the proper punctuation or conjunctions needed to hold them together in a grammatically correct way. There are many types of run-ons. We’ll cover the three most common. 

1. Comma splices

A run-on sentence with a comma splice consists of two independent clauses separated by a comma and missing a conjunction—for example:

I need a new TV, mine’s broken.

The movie was good, the special effects were awesome.

These could be corrected in a number of ways. The two clauses could be made separate sentences:

I need a new TV. Mine’s broken.

The writer could replace the comma with a semicolon:

The movie was good; the special effects were awesome.

An em-dash can do the same thing:

I need a new TV—mine’s broken.

With a subordinating conjunction, one clause could become dependent on the other:

Because the special effects were awesome, the movie was good.

Or the writer could link them with a coordinating conjunction:

My TV’s broken, so I need a new one.

2. Two sentences crammed together

Other run-on sentences consist of two independent clauses crammed together with no punctuation—for example:

Let’s go it’s getting hot.

All the comma splice solutions apply here as well:

Let’s go. It’s getting hot.

Let’s go; it’s getting hot.

Let’s go—it’s getting hot.

Since it’s getting hot, let’s go.

It’s getting hot, so let’s go.

3. Conjunction misuse

Another common type of run-on sentence involves misuse of conjunctions, especially however, often with a comma splicefor example:

I have kits to assemble, however, I have no bags.

Here, there’s a comma splice after I have kits to assemble. This common error probably results from confusion with perfectly acceptable constructions like this:

Over many years of jurisprudence, however, the Supreme Court has ruled that most of the rights protected in the Bill of Rights also apply to the states. [SCOTUS Blog]

This however works because it functions adverbially (here it is synonymous with though). The however in the first example is a coordinating conjunction, so its clause should be treated as independent.

2 thoughts on “Run-on sentences”

  1. re: ‘however’: You should explain in the last example that the reason that ‘however’ is allowed is because of the sentence that would’ve appeared before it. It doesn’t really makes sense in isolation. The sentence before it should be shown, not just meaning implied.
    ‘However’ is used when there are two ideas: one idea is given in the first sentence. In the second sentence you give the other idea, along with the word ‘however’.


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