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Identifying and Fixing Run-On, Fused Sentences

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A fused sentence is a type of run-on sentences. A common problem in writing, fused sentences result from joining sentences improperly. In this lesson, you will learn how to identify and fix fused sentences.

What Is Run-On, Fused Sentence?

When you write two complete, independent sentences back to back without joining them properly, you end up with a fused sentence. Here is a simple example:

The students were exhausted they had been studying through the night.

Notice that the above example has two independent sentences that can be written as separate ideas:

The students were exhausted.

They had been studying through the night.

Writing them as a fused sentence, it is difficult to tell where one sentence ends and a new sentence begins. This can be confusing—and annoying—to your readers.

Example Fused Sentences

Each of the following sentences are fused sentences. Notice how each sentence has complete, independent ideas without any punctuation or conjunction between them.

(1) Researchers conducted a study they wanted to investigate whether children preferred printed books to laptops.

(2) The children were observed during a lesson the researchers did not interact with them.

(3) The study showed interesting results many of the children would rather use laptops than read printed books.

Notice how it takes you a few seconds to tell each sentence apart. We will see how to fix the issue in the next section.

Identifying and Fixing Fused Sentences

As you could probably tell in the above examples, it is fairly easy to detect a run-on. Whenever you have two independent sentences that make sense on their own, you should not write them back to back without punctuation. Similarly, when you use a comma where a period should be used to separate two independent sentences, you end up with another type of run-on sentence, a comma splice. (Comma splices are not addressed in this lesson.)

When you have two independent sentences, you should either separate them with terminal punctuation (i.e., a period, question mark, or exclamation point) or join the two sentences, for example, using a coordinating conjunction (e.g., and, or, so, and so on).

Let’s go over the run-ons in the examples above and see how they can be fixed.

Fused Sentence 1

Researchers conducted a study they wanted to investigate whether children preferred printed books to laptops.

Correction 1. Use punctuation to write two independent sentences.

Researchers conducted a study. They wanted to investigate whether children preferred printed books to laptops.

Correction 2. Combine the two sentences into one. (This correction yields better results in this example.)

Researchers conducted a study to investigate whether children preferred printed books to laptops.

Fused Sentence 2

The children were observed during a lesson the researchers did not interact with them.

Correction 1. Use punctuation to write two independent sentences.

The children were observed during a lesson. The researchers did not interact with them.

Correction 2. Combine the two sentences into one.

(a) The children were observed during a lesson, so the researchers did not interact with them.

(b) The children were observed during a lesson; therefore, the researchers did not interact with them.

Fused Sentence 3

The study showed interesting results many of the children would rather use laptops than read printed books.

Correction. Use punctuation to write two independent sentences.

The study showed interesting results. Many of the children would rather use laptops than read printed books.

Assess Your Learning

Practice 1. Practice identifying and fixing run-ons.

Related Lessons

The following lessons are related to identifying sentence issues while editing your writing.

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