Explanation

We have already done the work means ہم پہلے ہی کام کرچکے ہیں

Active Voice: We

Passive Voice: By us

Active sentences in the present perfect tense have the following structure:
Subject + has/have + past participle form of the verb + object
Passive sentences in the present perfect tense have the following structure:
Object of the active sentence + has/have + been + past participle form of the verb + by + subject of the active sentence

Explanation

The obstacle course was run by me in record time.

This is the passive voice of the active sentence "I ran the obstacle course in record time."

In passive voice: Object + was/were + past participle + by + subject

Explanation

Active voice: Who

Passive voice: By whom

Active: Who painted it?

Passive: By whom was it painted?

Explanation

This is future simple tense ("will repair"), so passive form is "will be + past participle".

"Repair" changes to "be repaired" and subject "He" becomes "by him" in passive voice.

Explanation

She takes tea.

Tea is taken by her.

Explanation

In passive voice, the subject receives the action, rather than performing it.

The sentence "The student was praised by the teacher" follows this structure, where "the student" is the receiver of the action.

Explanation

The traitors should be shot dead.

In passive voice, the subject (traitors) receives the action, and the auxiliary verb "should" remains unchanged.

The structure changes from "They should shoot" to "The traitors should be shot."

Explanation

Explanation

Explanation

The windows have been cleaned by the butcher.

The sentence is in present perfect tense: has cleaned.

In passive voice, it becomes: have been cleaned (for plural subject: the windows).