Sentence fragments are groups of words that don't express complete thoughts. They are only fragments of sentences.
On the table. Over there. If I walk home.
They are fine to use in conversation or in informal writing, but they are a no-no when it comes to formal writing. We talk about sentence fragments in contrast to complete sentences. A complete sentence expresses a complete thought. Here are a few complete sentences.
My hat is on the table.
The dog ran over there.
I'll call you if I walk home.
When a group of words is missing important information, it no longer expresses a complete thought.
There are four possible reasons for why a group of words is a fragment.
1. It is missing a subject.
2. It is missing a verb.
3. It is missing a subject and a verb.
4. It is a subordinate clause.
Let's look at each of those reasons, shall we?
1. Missing Subjects
Subjects tell whom or what sentences are about.
If the subject is missing, we are left wondering who or what performed the action.
Ran around the tree. (Who ran around the tree?)
Will walk into the room. (Who will walk into the room?)
Shot through the sky. (What shot through the sky?)
We can fix each of those fragments and turn them into sentences by adding a subject.
The dog ran around the tree.
The President will walk into the room.
A rocket shot through the sky.
Yippee! Now they are all complete sentences!
2. Missing Verbs
Verbs tell what the subject did or is.
If the verb is missing, we are left wondering what the subject did or what the subject is.
My little sister. (My little sister did what?)
My cute little dog. (The cute little dog did or is what?)
We can fix these types of fragments by adding a verb.
My little sister ran away.
My cute little dog is cuddly.
Now, both of those groups of words are complete sentences.
3. Missing Subject and Verb
Some fragments are missing both subjects and verbs. That means that we don't know whom the sentence is about or what they did or are.
On the table.
Do you know how to change these from fragments into complete sentences?
You guessed it! We need to add a subject and a verb.
The corn is on the table.
My doggie ran over there.
Those two groups of words are now complete sentences.
4. Dependent Clause
Subordinate clauses (dependent clauses) are groups of words that contain a subject and a verb, but they don't express complete thoughts. If you use them alone, they are sentence fragments.
Whenever I walk the dog.
Until my little sister walks into the room.
You can fix these kinds of fragments by connecting dependent clauses to independent clauses. Independent clauses are groups of words that contain a subject and a verb, and they also express complete thoughts. You can add independent clauses before or after dependent clauses.
Whenever I walk the dog, I feel great.
Here, I added I feel great, an independent clause, after the dependent clause. If you add your independent clause after the dependent clause, notice that you need to use a comma to separate them.
I will stay here until my little sister walks into the room.
For this one, we added the independent clause I will stay here before the dependent clause. When you do this, you don't need a comma between the two.
Test Yourself on Sentence Fragments
Use this grammar quiz on fragments and run-on sentences.
You'll find everything you need to test yourself or your students.
Now that you know about sentence fragments, it's time for you to learn about sentence diagramming!
If you'd like to teach or learn grammar the easy way—with sentence diagrams—check out our Get Smart Grammar Program.
It starts from the very beginning and teaches you grammar and sentence diagramming in easy, bite-size lessons.