This worksheet was created to be used at the same time as passive voice is taught. I have a slightly different approach to it. I don't expect my students to memorize the active and passive form of the verbs. I explain how to add the verb To Be in the same tense as the main verb and add the past participle of the main verb. Then I explain the "who" and the "what" of the main verb and how to change the order in the passive sentence. Then just start turning active sentences into passive.
I know it is unconventional ... I have a terrible time memorizing things so I came up with this different approach. I have been using it for 20+ years and my students have passed FCE and other exams and use it regularly both when they write and talk. Hope it helps!