Passive voice is a grammatical construction where the subject of a sentence receives the action expressed by the verb. In passive voice sentences, the object of the action becomes the subject of the sentence, while the doer of the action (if mentioned) typically appears in a prepositional phrase or is omitted altogether. Passive voice is characterized by a structure where the object comes before the verb. While sometimes necessary or appropriate, passive voice can make sentences less direct and may obscure the doer of the action. For example, in the sentence "The mouse was chased by the cat," "the mouse" is the subject receiving the action of "being chased," making it a passive voice sentence.