Voice, in grammar, is a feature of transitive verbs. A transitive verb is a verb that takes a direct object. Voice tells whether the subject of the verb acts or is acted upon. English has two voices, active and passive.
A verb is in the active voice when its subject is the doer of the action. For example, the verb is in the active voice in the sentence John sees the picture, because the subject (John) performs the action (sees).
A verb is in the passive voice when its subject receives the action. In The picture was seen by John, the subject (picture) receives the action (was seen). The verb is therefore passive. In English, the passive voice consists of some form of the verb be (such as is, was, were, or been), plus the past participle of the main verb (such as seen). Passive forms of see include is seen, was seen, were seen, will be seen, have been seen, is being seen, and was being seen. Only transitive verbs can be changed to passive voice.
