A sentence fragment is an incomplete sentence that cannot stand by itself because there is a subject and/or a main verb missing. Unless they are used to convey a certain style, sentence fragments should be avoided because they are gramatically incorrect. Examples of sentence fragments are "swam by the river" or "Throughout the novel, the author". On the other hand, a run-on sentence is a sentence that contains two or more independent clauses that have been connected in an improper way. Examples of run-on sentences are "My sister is sick we are not going to the beach" "I studied for the test I arrived late".