The impersonal passive voice is a verb voice that decreases the valency of an intransitive verb (which has valency one) to zero. The impersonal passive deletes the subject of an intransitive verb. In place of the verb's subject, the construction instead may include a syntactic placeholder, also called a dummy. This placeholder has neither thematic nor referential content. (A similar example is the word "there" in the English phrase "There are three books.") In some languages, the deleted argument can be reintroduced as an oblique argument or complement. Test of unergative verbs In most languages that allow impersonal passives, only unergative verbs may undergo impersonal passivization. Unaccusative verbs may not. The ability to undergo this transformation is a frequently used test to distinguish unergative and unaccusative verbs. In Turkish, for example, the verb çalışmak "to work" is unergative and may therefore be passivized: The verb ölmek "to die", however, is unaccusative and may not be passivized: In a passive construction with an unergative verb, the unexpressed agent is understood to be an indefinite human agent. Examples Dutch The Dutch impersonal passive can be seen in the following sentences. {| | [De || jongens]s || fluiten. |- | the || boys || whistle |- | colspan=3| "The boys are whistling." |} {| | Er || wordt || ([door || de || jongens]) || gefloten. |- | there || is || by || the || boys || whistled |- | colspan=6 | "There is whistling (by the boys)." |} German German has an impersonal passive voice, as shown in the examples below: Active voice: Impersonal passive voice: In the latter example, the subject (Die Kinder, "the children") has been deleted, and in its place is the dummy es "it". The sentence can be constructed without an overt subject by placing an adverbial in the first position: Venetian Venetian has the impersonal passive voice, also called intransitive passive, since it is built from intransitive verbs. The verb parlar "to speak" is intransitive and takes an indirect object marked by a "to" or by co "with": although there is no direct object to be promoted to subject, the verb can be passivized becoming subjectless, i.e. impersonal. The usual auxiliary "to be" is employed, in the form xe "is" (with zero-dummy) or in the form gh'è "there is" (with gh'-dummy) depending on the local variety. Xe stà parlà co Marco? has DUMMY been spoken to