Theory:

Voice: The voice of a verb tells whether the subject of the sentence performs or receives the action.
Example:
i) Raccoon build nests. (Active voice)
ii) Nests are built by Raccoon. (Passive voice)
Types of Voice:
Active Voice: the subject performs the action expressed by the verb.
Usage: when more clarity and straightforward relation is required between verb and subject.
 
Passive Voice: the subject receives the action expressed by the verb.
Usage: when the action is the focus, not the subject or when the doer is unknown.
Rules of Conversion from Active to Passive Voice:
Important!
1. Identify the subject, the verb and the object: S+V+O
2. Change the object into subject
3. Put the suitable helping verb or auxiliary verb
4. Change the verb into past participle of the verb
5. Add the preposition "by“
6. Change the subject into object
Example:
Active Voice: Sajid wrote an email.
(Subject) + (verb) + (object).
 
Passive Voice: An email was written by Sajid.
(Object) + (auxiliary verb) + (past participle) + (by subject).
The passive verbs are created by combining a form of the "to be verb" with the past participle of the main verb. Passive Voice for all tenses:
The rules for using Auxiliary verb for Passive Voice is different for each tense.
1. Simple Present Tense:
Example:
Active Voice: She writes a letter.
Passive Voice: A letter is written by her.
2. Present Progressive Tense:
Example:
Active Voice: They are eating apples.
Passive Voice: Apples are being eaten by them.
3. Present Perfect Tense:
Example:
Active Voice: Has she completed the class work?
Passive Voice: Has the class work been completed by her?
4. Simple Past Tense:
Example:
Active Voice: He did not buy a fiction book.
Passive Voice: A fiction book was not bought by him.
5. Past Progressive Tense:
Example:
Active Voice: She was washing a skirt.
Passive Voice: A skirt was being washed by her.
6. Past Perfect Tense:
Example:
Active Voice: They had won the football match.
Passive Voice: The football match had been won by them.
7. Simple Future Tense:
Example:
Active Voice: Rani will write a poem.
Passive Voice: A poem will be written by Rani.
8. Future Perfect Tense:
Example:
Active Voice: He will have received the greeting card.
Passive Voice: The greeting card will have been received by him.
Passive voice used in the lesson "The Last Stone Carver":
  1. His face was ashen.
  2. It was a month since Gopal had left.
  3. The hammer and chisel were flung by the young man.
  4. He was driven by the strong desire to finish the sculpture in time.
  5. The young man cried that he was leaving.
  6. His arms were spread out.
  7. The white washed walls were stained by monsoons.
  8. The congested workroom was glanced.
  9. He was back!
  10. He was about to shout when the words froze on his lips.
  11. My strength is waning.
  12. The white washed walls were stained by many monsoons.