Complete Sentences and Consistent Verbs

Sentence Boundaries: Complete Sentences vs. Sentence Fragments

A complete sentence expresses a complete thought and has a finite verb and a subject, which may be understood rather than stated in an imperative such as “Stop.” An independent clause meets all these requirements because it contains a subject and a verb and can stand alone as a complete sentence. When an incomplete grammatical unit lacks a subject, a verb, or a complete thought, it is classified as a sentence fragment.

One frequent source of fragments is a dependent clause punctuated as an independent sentence. A dependent clause has a subject and a verb but cannot stand alone as a complete sentence; it often begins with a subordinating conjunction such as because, although, since, if, unless, or while, or with a relative pronoun. Punctuating such clauses with a period instead of attaching them to an independent clause creates a fragment.

Other common fragments arise from standalone phrases. A participial phrase beginning with an -ing verb cannot stand alone as a complete sentence; it must be attached to an independent clause or revised to include a subject and a finite verb. Similarly, an infinitive phrase consisting of the word to followed by a base verb is a fragment if punctuated as a standalone sentence. Prepositional phrases cannot stand alone regardless of their length, and appositive phrases that rename an adjacent noun constitute fragments when punctuated as independent units.

To correct a fragment, you can attach it directly to an adjacent independent clause with appropriate punctuation, or you can add the missing subject or finite verb. Dependent-clause fragments can either be linked to an independent clause or revised to stand alone. Note that informal workplace emails often contain fragments that omit the subject pronoun; in formal contexts, these omitted pronouns should be restored.