 Passive voice. How to construct the passive? One, check to see if the active sentence contains an object. John ate an apple. Subject, verb, object. Passive is possible. John ate yesterday. Subject, verb. Passive is not possible. Two, move the object to the front of the sentence. Put the original subject in a by phrase. An apple, verb, by John. Three, put the verb in the form B plus 3 of main verb. For simplicity, we use numbers here to refer to verb forms. One, base form, eat. Two, past form, ate. Three, past participle form, eaten. An apple, be eaten by John. Four, put the B in the same tense as the original active sentence. An apple was or were eaten by John. Past tense. Five, make the first verb agree with the new subject. An apple was eaten by John. Put the other elements of the sentence in grammatical and logical order. Yesterday, the large green apple was quickly eaten by John, who didn't realize that it belonged to his sister. When other auxiliary verbs and modals are used in combination with the passive, remember B plus 3, passive. B plus verb, I-N-G, progressive. Have plus 3, perfect. Modal plus 1, modal. The apple should have been being eaten by John. In combination of auxiliary verbs with the passive, B plus 3, passive. B plus verb, I-N-G, progressive. Have plus 3, perfect. Modal plus 1, modal. The apple is eaten by John. Present tense. The apple was eaten by John. Past tense. The apple is being eaten by John. Present progressive. The apple was being eaten by John. Past progressive. The apple has been eaten by John. Present perfect. The apple had been eaten by John. Past perfect. The apple has been being eaten by John. Present perfect, progressive. The apple had been being eaten by John. Past perfect progressive. The apple will be eaten by John. Future or modal? The apple is going to be eaten by John. Future or modal? The apple must be eaten by John. Modal. The apple must have been eaten by John. Past modal. The apple must have been being eaten by John. Combination.