This is a sentence of Present Indefinite Tense.
Present Indefinite Tense
Active Voice: Subject + Verb + Object
Passive Voice: Object + is/am/are+ third form of a verb + by + subject.
Active Voice = Subject + believe/find/claim/consider/know/report/say/think/ + that + clause.
Passive Voice = It + be + third form of a verb + clause.
Please /kindly → You are requested to. You are requested + rest of sentence.
Note: Please and kindly are not used in passive voice.
Active Voice: I do not like people hating me.
Correct Passive Voice: I do not like being hated.
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He is singing a song.
To convert the active sentence into passive form, the "object of the active" sentences is considered as the "subject of the passive" sentence.
Here is a given sentence is in present continuous tense. So, the given sentence is converted into "present perfect continuous" tense.
"A song is being sung by him"
The given sentence contains one of Model verb (Model Verb = will, shall, can, may, might, could, might, must, would). It is in active voice. Formula: Model verb + be + V3 + Optional Objects + ?
Active Voice = Subject + verb + Noun/Pronoun + to + first form of a verb + Object.
Passive Voice = Subject + verb + Object + to be + third form of a verb + by + noun.
Past Indefinite tense
Active Voice= Subject + Second Form of Verb + Object.
Passive Voice = Object + was/were + third of verb + by + subject.
Active Voice: Let + indirect object + first form of a verb + direct object.
Passive Voice: Let + direct object + be + third form of a verb + by + indirect object.
"Most of the floor had been covered by the rug" is the correct passive voice transformation.