• Recognize sentence fragments
• Revise sentence fragments
• Recognize run-on sentences
• Revise run-on sentences

Sentence Structures to Prevent Fragments and Run-Ons

Most errors at the sentence level have to do with comma splices, sentence fragments, and run-on sentences. In other words, there may be issues with using commas, writing complete sentences, or editing long sentences. 

Here’s a simple way to think about it.

You can combine two sentences with a comma and a conjunction: Sentence, conjunction sentence.

• I love reading, and he loves writing.

You can also separate out your two sentences with punctuation like a period: Sentence. Sentence.

• I love reading. He loves writing.

You cannot combine two sentences with just a comma and no conjunction (that’s a comma splice):

• Incorrect: Sentence, sentence
• Incorrect: I love reading, he loves writing.

You could fix this sentence by adding in a conjunction like “and” or “but.” You can also fix this issue by using a semicolon. A way to remember this is to think about the semicolon as working like a period.

• Sentence; sentence.
• I love reading; he loves writing.

Using a semicolon to combine two complete sentences is an easy way to vary your sentence construction and avoid short choppy sentences. As long as you remember that your semicolon needs to connect two complete sentences, you will be set.

Let’s try some examples where you finish the sentence.

Guess what, there’s one more fun way to avoid the dreaded run-on or comma splice. Use a colon. It’s easy: A colon works just like a period.

• Sentence: Sentence.
• Sentence: anything (but not a full sentence).

Remember when you use a colon you are combining two sentences so they need to be closely related. Usually the second sentence is explaining something about the first sentence. Here are two examples:

• Sentence: Sentence.
  • I love eating out: McDonald’s is awesome.
• Sentence: not a full sentence.
  • I love eating out: anything but McDonald’s.

In summary, you have a variety of options for combining sentences and using appropriate punctuation to prevent fragments or run-ons:

• Sentence. Sentence.
• Sentence, conjunction sentence.
• Sentence; sentence.
• Sentence: Sentence.
• Sentence: anything but a sentence.