Question

Change to passive voice who did this?

Answer 1

Hint: The subject of an active voice phrase is a subject who acts on the verb. A subject gains from the action of a verb in passive voice. In the passive voice, the verb operates on the subject.

Complete answer:
The active voice is a grammatical notion that defines sentences in which the verb's activity is actively carried out by the subject of the sentence.
In grammar, voice refers to the relationship between a sentence's action and the person (or people) who execute (or do not perform) the action.

In active voice, the subject of the sentence is the recipient of the verb's action, whereas in passive voice, the subject is the recipient of the verb's action. Consider the case below:

The girl ate the apple (active speech).
The apple was eaten by the girl. (passive voice).

When a verb acts on the subject of a sentence, it is said to be in the passive voice. In "The ball was thrown by the pitcher," for example, the ball (the subject) receives the verb's action and is thrown in the passive voice.

Following this rule, in the above phrase, the subject becomes the object, and the object becomes the subject in the passive voice.
Currently, the subject is "who," and the object is "this."
Who, on the other hand, is exclusively employed as a subject. It becomes whom when the same interrogative (question word) is placed after a verb or preposition.
When using passive forms, the word 'by' must be used to indicate the action's agent. The preposition is 'by' in this case.

The sentence takes on a passive form: This was done by whom?

Note: Some rules of Active/Passive voice are:
- Find the (S+V+O) subject, verb, and object in the active sentence to convert to passive voice.
- In the active and passive sentences, swap the object and subject so that the active sentence's object becomes the passive sentence's subject.
- The subject is not always needed in passive voice; for example, if the statement makes sense without it, the subject may be dropped.