Explanation

Passive voice: Did you do it on purpose?

Active voice: Was it done by you on purpose

 (was /were) + subject + V3 + Optional Agents.

Explanation

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

The sentence is in Simple Past Tense.

Explanation

Present continuous tense in active becomes "is/are being + past participle" in passive.

“Are baking” becomes “are being baked.”

Explanation

• The correct answer is: Grass is not eaten by a lion, however hungry he may be.
• This sentence is in the passive voice, whereas the original sentence "Lion does not eat grass, however hungry he may be"
• is in the active voice.
• In the passive voice, the focus is on the grass (the object) rather than the lion (the subject),
• and the verb phrase "is not eaten" is in the passive form.

Explanation

The sentence is in present continuous tense ("are telling"), so the passive form uses "is being told."

"You" becomes "by you" and "the truth" becomes the subject in the passive voice.

Explanation

The house was built by my father.

The original sentence is in simple past tense ("built"), so the passive form should be in simple past too.

Passive voice: Subject + was/were + past participle + by + agent.

Explanation

Use the correct form of the verb "be" according to the modal ("must be").

Use the past participle of the main verb ("help" → "helped").

 Add the agent (the doer of the action) at the end if needed ("by you").

So,  

Active: You must help me.  

Passive: I must be helped by you

Explanation

The correct passive voice sentence is:

Honesty is said to be the best policy but it is seldom acted upon.

"People say" becomes "is said"

"they seldom set upon it" becomes "it is seldom acted upon"

Explanation

Can I ever forget those happy moments?

The sentence is changed from passive to active voice, maintaining the same meaning while restructuring it.

Explanation

By whom was this article written?

This is the correct passive voice form of the question "Who wrote this article?"

"By whom" is the grammatically correct formal structure for starting a passive question.