Answer:
By whom has this letter been torn?
Step-by-step explanation:
The passive voice of the sentence "Who has torn this letter?" is:
By whom has this letter been torn?
To change a sentence from active voice to passive voice, we need to:
- Make the subject of the active voice the object of the passive voice.
- Change the verb to the passive form.
- Add a prepositional phrase beginning with "by" to indicate the agent of the action.
In the active voice sentence, the subject is "who" and the verb is "has torn."
In the passive voice sentence, the object is "this letter" and the verb is "has been torn."
The prepositional phrase "by whom" indicates the agent of the action, which is the person who tore the letter.