Many writers struggle with sentence-boundary issues. The two biggest sentence-boundary issues are fragments and run-on sentences. This page gives you information about these issues and shows you different strategies for finding and fixing them.
Independent Clauses
To fix sentence-boundary issues, it’s important to understand two different types of clauses. Let’s start with independent clauses. An independent clause is a group of words that can stand alone as a complete thought. Every sentences needs three things to exist:
- A subject (the main actor in the sentence)
- A main verb (the main action of the sentence—sometimes called a “predicate”)
- A complete thought
An independent clause can be its own sentence. This, for example, is an independent clause:
Derek watched Game of Thrones in one week.
In this independent clause, “Derek” is the subject and “watched” is the main verb. It expresses a complete thought.
Dependent Clauses
As its name suggests, a dependent clause is not independent—it depends on something else to exist. However, dependent clauses can be tricky because they have two of the three things independent clauses have: a subject and main verb. What’s missing, though, is a complete thought. Here are some examples of dependent clauses:
- After we run by the store.
- If you decide to buy the refrigerator.
- Since we didn’t go see the movie.
You might notice that these dependent clauses start with words that suggest something comes after the sentence. (What happens AFTER we run by the store? What happens IF we buy the fridge?) Dependent clauses often begin with prepositions (“after”) or subordinating conjunctions (“if” and “since”). If someone were to give a speech consisting just of these sentences, the audience would be completely unsatisfied and not a little baffled.
Fragments
A fragment is an incomplete sentence. There are two ways that sentence fragments happen. First, they could be missing either a subject or main verb (or both!). Here are some fragments that lack those things:
- Went home in a fit of anger.
- Dave, since he was already home.
- Reading this book for what feels like hours.
Secondly, fragments can be dependent clauses masquerading as complete sentences. These are often the trickiest to spot and correct. If you have trouble finding these types of fragments, you might try reading your writing out load (your ear can sometimes catch these errors better than your eye).
Run-ons
Run-on sentences have the opposite problem that fragments have. There’s too much sentence! Technically speaking, run-on sentences happen when there are two or more independent clauses in a sentence that are incorrectly punctuated.
Here’s an example of a run-on sentence:
I love this new Dave Matthews Band record it is like eating an entire loaf of bread.
There are two independent clauses here: 1) “I love this new Dave Matthews Band record” 2) “it is like eating an entire loaf of bread.” This sentence can be very confusing to a reader because we are taught to expect one complete thought per sentence. There are a few ways we can fix this run-on.
- Break it into separate sentence. Since a run-on has two or more independent clauses (and since an independent clause can stand alone as its own sentence) you can turn each independent clause into its own sentence.
- → I love this new Dave Matthews Band record. It is like eating an entire loaf of bread.
- Add comma with a coordinating conjunction (FANBOYS). These seven small joining words (For, And, Nor, But, Or, Yet, and So) can hook up independent clauses with a comma. But be careful! A comma by itself can’t join independent clauses—that would be a “comma splice,” a type of a run-on.
- → I love this new Dave Matthews Band record, and it is like eating an entire loaf of bread.
- Add a semicolon. Semicolons can join closely related independent clauses. You don’t use FANBOYS when using a semicolon like this.
- → I love this new Dave Matthews Band record; it is like eating an entire loaf of bread.
- Add a subordinating conjunction. You can turn one of the independent clauses into a dependent clause to fix a run-on sentence.
- → I love this new Dave Matthews Band record because it is like eating an entire loaf of bread.
Finding and Fixing Fragments & Run-ons
Fixing sentence-boundary errors is relatively easy once you understand what each sentence needs. Finding them in your writing is more challenging. These tips can help you practice finding sentence-boundary errors.
- Read your writing out loud. Often, your ear will catch incomplete thoughts and sentences with more than one complete thought better than your eyes.
- Turn your sentences into yes/no questions. For example, you might ask “Do I love this new Dave Matthews Band record it is like eating an entire loaf of bread?” That helps you find sentences with more than one main idea/independent clause.
- Look for sentences with commas in the middle of the sentence. These often have higher chances than usual of being comma splices.
- Look for sentences beginning with prepositions, subordinating conjunctions and words ending in “-ing.” These often have higher chances of being fragments.
Works Consulted
- “Avoiding Fragments with Dependent Clauses.” The Writing Center. The Writing Center at George Mason University, 2018. writingcenter.gmu.edu/guides/avoiding-fragmentswith-dependent-clauses. Accessed 2 July 2018.
- “Fragments and Run-ons.” The Writing Center at UNC-Chapel Hill, 2018. writingcenter.unc.edu/tips-and-tools/fragments-and-run-ons/. Accessed 2 July 2018.
- “Run-on Sentences.” The Writing Center. The Writing Center at George Mason University, 2018. writingcenter.gmu.edu/guides/run-on-sentences. Accessed 2 July 2018.
- “Fragments and Run-Ons.” The OWL at Purdue. Purdue University, 2018. owl.english.purdue.edu/engagement/2/1/33. Accessed 2 July 2018.
