Every transitive verb can appear in one of two voices: the active voice or the passive voice.
In the active voice, the grammatical subject of the sentence is the actor. Thus, in the following sentence, the actor is the subject of the sentence. The subject is active. The verb, therefore, appears in the active voice:
John hit the ball.
In the passive voice, what was the direct object in the active voice (ball) becomes the grammatical subject in the passive voice. Thus, in the following sentence, the grammatical subject is passive, that is, the subject receives the action denoted by the action verb in the passive voice:
The ball was hit by John.
To form the passive voice, take any form of the verb to be and add the past participle of the transitive verb.
Here's a table showing a conjugation of the verb to show in the active voice and in the passive voice. Please notice that in the progressive tenses, we can conjugate in the passive only the present progressive and the past progressive. There is no future progressive in the passive voice. Likewise there are no perfect progressives in the passive voice. If we had a future progressive, it would appear like this: The movie will be being shown. If we had a perfect progressive, it would appear like this: The movie has been being shown. Those constructions simply do not exist in the English language.
|John||shows||the movie||is shown||by John|
|will show||will be shown|
|has shown||has been shown|
|had shown||had been shown|
|will have shown||will have been shown|
|is showing||is being shown|
|was showing||was being shown|
|will be showing||Doesn't exist
(will be being shown)
|has been showing||Doesn't exist
(has been being shown)
|had been showing||Doesn't exist
(had been being shown)
|will have been showing||Doesn't exist
(will have been being shown)