according to wiki ( ):

A run-on sentence is a sentence in which two or more independent clauses (that is, complete sentences) are joined with no punctuation or conjunction.

Independent clauses: clauses that are complete with a subject and a predicate.

ie: I watched TV last night, the dog was also walked, but I wasn't the one who walked it my sister was the one who did the walking.
4 independent clauses, but only 1 conjunction "but". So either use other conjuctions, or use a period.


A sentence fragment is an incomplete sentence; a phrase or clause that is punctuated and capitalized as a sentence but does not constitute a complete grammatical sentence. It is usually caused by the failure to include a subject and a verb in a sentence or as the result of beginning a sentence with a subordinate conjunction or relative pronoun.

ie: While watching TV, the dog, tired from getting walked by my sister, who finished her homework early that night.

The main subject is "the dog", but there's no predicate. What did the dog do?