Final answer:
A phrase or a clause that does not form a full sentence can lead to sentence fragments or run-on sentences. A phrase lacks a subject-verb unit, while a clause contains both but may not express a complete thought if it is dependent.
Step-by-step explanation:
A word, phrase, or clause that does not form a full sentence is typically referred to as a sentence fragment or a phrase. A phrase is a group of words that functions as a unit within a sentence but lacks the subject-verb component necessary to form a complete thought.
In contrast, a clause contains both a subject and a verb, and can be independent (able to stand alone as a full sentence) or dependent (cannot stand alone as a full sentence). It's important to recognize that a dependent clause can sometimes be mistaken for a complete sentence, which leads to the creation of sentence fragments.
To avoid unintentional sentence fragments, one can attach the fragment to the sentence it belongs to or rewrite it as a complete sentence. Conversely, independent clauses can sometimes run together without appropriate punctuation or conjunctions, creating run-on sentences.
These can be fixed by adding a period, semicolon, or coordinating conjunction to properly separate the clauses.