In the English language, for a complete sentence, two components are needed:
When one of these two items are missing, a complete thought is lacking; therefore, we have what is known as a fragment.
A sentence fragment does not express a complete thought and is missing some vital information.
Examples of Fragments
1. Reached the beach early. (No Subject)
2. The rain muddy and wet after storm. (No Verb)
3. Because we were running late. (Not a complete thought)
For a review on complete sentence structure, please visit the sentence writing page.
To identify if a group of words is a fragment, follow the provided steps.
Another cool way to identify if a group of words is a fragment, is offered by linguist, Rei Noguchi.
Simply add the words "I know that . . ." to the front of a group of words to verify if you have a sentence or a fragment.