Read the following sentences:
1. Active: Does Saritha like ice-cream?
Passive: Is ice-cream liked by Saritha? (NOT Do ice cream liked by the children?)
2 Active: Did you heat the water?
Passive: Was the water heated by you? (NOT Did water heated by you?)
Note The auxiliaries do, does and did are not used in the passive.
Active:Have you completed your homework?
Passive: Has your homework completed by you?
Note: The auxiliaries has, have and had were used in the passive, but they change their form according to the number and person of the passive subject.
Active: Can we break it?
Passive: Can it be broken?
Active: Will he invite us?
Passive: Will we be invited by him?
Note:The auxiliaries can, may, will and shall do not change their beginning position when active voice is changed into the passive voice.
Active: Whom did you laugh at?
Passive: Who was laughed at by you?
Active: Who bought the new car?
Passive: By whom was the new car bought?
Note: Who changes to, "by whom" in the passive: (by) whom changes to who in the passive.
Active: Why did he bring the cabs?
Passive: Why were the cabs brought by him?
The question words when, where, how, why and what do not change their beginning position when the sentence is changed from the active to the passive.