1. A sentence fragment is an incomplete sentence because it is missing an essential part (subject, verb, or object) necessary to achieve complete meaning within the sentence itself.

INCORRECT
Information presented here. It is necessary to understand the following pages.
CORRECT
Information is presented here because it is necessary to understand the following pages.

2. Sentence fragments often occur from an addition to an existing
thought.
INCORRECT
Let's visit the city art museum. Norman Rockwell's exhibit displayed.
CORRECT
Let's visit the city art museum; Norman Rockwell's exhibit is displayed.
3. Fragments are usually phrases or dependent clauses which should be part of the preceding sentence.
INCORRECT
Ms. Smith has enjoyed teaching children for years. Although the children wish she would use computers in class.
CORRECT
Ms. Smith has enjoyed teaching children for years, although the children wish she would use computers in class.