Identifying and Fixing Run-ons and Sentence Fragments

Identifying and Fixing Run-ons and Sentence Fragments

In order for a sentence to be grammatically correct, it requires three things: a predicate, a subject, and an independent clause. The predicate refers to the action (or verb) of the sentence, the subject is who performs the action, and the independent clause means that it expresses a complete thought. For example, “Peter ate” is a full sentence (though a short one) because it fulfills these three criteria. However, most sentences are longer than just two words. What did Peter eat? When? Where?

As writers begin adding clauses and information to sentences, it becomes more difficult to maintain the three criteria of a sentence. The most common errors in sentence structure fall broadly into two categories: sentence fragments and run-on sentences.

Sentence Fragments

The definition of a fragment is “a piece of something, rather than the whole.” Therefore, a sentence fragment refers to only part of a sentence because one (or more) of the three criteria is missing. Let’s look at a few examples.

1.     The sentence is missing a subject.

This is a common error for new writers. If you can’t answer the question, “Who did it?” when reading a sentence, then the sentence is a fragment. For example, in the fragment, “Ate some watermelon,” who ate some watermelon? You? Fred? George? Adding a subject, like, “Percy ate some watermelon,” fixes the sentence.

2.     The sentence is missing a verb/predicate.

This is the opposite problem of #1. If you write “Dog ground,” it would be a sentence fragment because it is missing a verb. What is the connection between the dog and the ground—is it lying on the ground, digging in the ground, sitting on the ground? A simple correction is to add a verb, as in, “The dog is sitting on the ground.”

3.     The sentence is a dependent clause.

So let’s assume a sentence has both a subject and a verb. If the sentence does not express a complete thought, it is called a dependent clause and is still a sentence fragment. Dependent clauses are particularly tricky for writers to catch, but a good rule of thumb is that if you see a word that indicates a logical relationship between two ideas—words like “because,” “although,” “however,” “since,” or “after”—the independent clause is going to follow.

For example, “Because Maria went to school” is a dependent clause because the thought is incomplete. The word “because” indicates that something happened when Maria went to school, but the sentence does not tell us what. The solution is to add an independent clause after the dependent clause: “Because Maria went to school, she had a lot of homework.”

Run-on Sentences

A sentence fragment is grammatically incorrect because it is missing one of the three criteria mentioned above. A run-on sentence is incorrect because it occurs when two or more independent clauses are joined without a word to connect them or a punctuation marking them as separate. Contrary to popular belief, a very long sentence is not necessarily a run-on sentence. The two most common types of run-on sentences fall into the following categories:

1.     Two or more independent clauses are joined with no punctuation or conjunction.

Have you ever asked little kids what they did on their first day of school? If you’ve heard an answer like, “I played on the playground I ate candy I had fun with my friends I took a nap,” then you’ve heard a run-on sentence. A simpler example of a run-on sentence might be, “Tara went to the beach she rode the bus home.” “Tara went to the beach” and “she rode the bus home” are both independent clauses because each has a subject, a verb, and a complete thought. This sentence can be fixed by:

·       Adding a conjunction like “and,” “but,” or “or”

“Tara went to the beach, and she rode the bus home.”

·       Separating the independent clauses into separate sentences using a period.

“Tara went to the beach. And she rode the bus home.”

2.     Comma splices

So inserting any punctuation (or the right words like conjunctions) between two independent clauses should fix the problem, right? Well, not exactly. A “comma splice” occurs when two independent clauses are separated only by a comma, not with a period or a conjunction. An example of this is, “Today I ate a cheeseburger, it was good.” “Today I ate a cheeseburger” and “It was good” are two complete sentences, but the comma suggests that they should be only one sentence. To fix a run-on sentence with a comma splice, either add a conjunction after the comma or replace the comma with a period to create two separate sentences. “Today I ate a cheeseburger, and it was good” is correct, and so is, “Today I ate a cheeseburger. It was good.”

Final Note

Sometimes when you read poetry or literature, you will notice that the writer uses sentence fragments or run-ons for rhetorical purposes. These writers are subverting traditional sentence structure intentionally, often to convey a certain voice or have a specific effect on the reader. Professional and academic writing is much more strict than creative writing when it comes to using correct sentence structure. So always know the rules before you try to break them!


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