Change to passive voice: Who did this?
1 Answer
This was done by whom? or By whom was this done?
Explanation:
The subject is currently "who" and the object is "this" - let's flip flop them:
This...who...
The "who" still performed the action on the "this", and so we need to alter the verb form to have that happen:
This was done by who?
However, who is only used for a subject. when the same interrogative (question word) is placed after a verb or preposition, it becomes whom.
With passive forms, 'by' must be used to refer to the agent - who is doing the action.
Here, 'by' is the preposition, so who? becomes by whom?
The passive form of the sentence becomes This was done by whom?.
For a more natural conversion, the word order can be inverted so that the interrogative, the words by whom?, come first.
This question would be By whom was this done?, and means the same as the alternative.
