**Rule**: When the active sentence uses 'had to' to show past necessity, the passive form is **Object + had to + be + V3**. - **Correct Answer (d)**: The object 'the naughty student' becomes the subject. The structure 'had to be punished' is the correct passive form for the past necessity. - **Incorrect Answer (a)**: 'had been punished' is the passive of the Past Perfect Tense ('had punished'), not 'had to punish'. - **Incorrect Answer (b)**: 'was to be' implies a past plan, which is a different meaning. - **Incorrect Answer (c)**: 'has to be' incorrectly changes the tense to the present.

**Rule**: The passive voice for the Past Perfect Continuous Tense is formed with **Object + had been + being + V3**. However, this construction is very rare and often considered awkward. It is usually rephrased. - **Correct Answer (b)**: This is the grammatically correct, though rarely used, passive form of the Past Perfect Continuous Tense. - **Incorrect Answer (a)**: This changes the tense to Past Continuous. - **Incorrect Answer (c)**: This changes the tense to Present Perfect. - **Incorrect Answer (d)**: This changes the tense to Past Perfect, losing the continuous aspect.

**Rule**: For an interrogative sentence in the Future Simple Tense starting with a 'Wh-' word, the passive structure is **Wh- word + will/shall + object + be + V3 + by + subject?** - **Correct Answer (a)**: The 'Wh-' word 'When' remains at the beginning. The modal 'will' is used, followed by the new subject 'the book', 'be', and the past participle 'returned'. - **Incorrect Answer (b)**: 'would' is an incorrect modal change. - **Incorrect Answer (c)**: This incorrectly changes the tense to Simple Present. - **Incorrect Answer (d)**: This incorrectly changes the tense to Future Perfect.

**Rule**: For a Present Continuous Tense sentence, the passive structure is **Object + is/am/are + being + V3 + by + Subject**. - **Correct Answer (d)**: The object 'a letter' becomes the subject. Since it is singular, 'is' is used, followed by 'being' and the past participle 'written'. - **Incorrect Answer (a)**: This incorrectly changes the tense to Simple Present. - **Incorrect Answer (b)**: This incorrectly changes the tense to Past Continuous. - **Incorrect Answer (c)**: This incorrectly changes the tense to Present Perfect.

**Rule**: Interrogative sentences in the Simple Past Tense starting with 'Who' are converted to passive voice using **By whom + was/were + object + V3?** - **Correct Answer (a)**: 'Who' becomes 'By whom'. The object 'this symphony' is singular, so 'was' is used, followed by the past participle 'composed'. - **Incorrect Answer (b)**: This incorrectly changes the tense to Simple Present. - **Incorrect Answer (c)**: The word order is incorrect, and 'who' should be 'whom' after a preposition. - **Incorrect Answer (d)**: This incorrectly changes the tense to Present Perfect.

**Rule**: For active sentences using the 'be going to' future form, the passive structure is **Object + is/am/are + going to be + V3**. The agent 'by them' can be omitted. - **Correct Answer (c)**: The object 'the entire building' becomes the subject. The structure 'is going to be renovated' is the correct passive conversion. The agent 'by them' is correctly omitted. - **Incorrect Answer (a)**: This changes the structure to the 'will' future. - **Incorrect Answer (b)**: This is the passive of the Present Continuous tense. - **Incorrect Answer (d)**: This incorrectly changes the tense to Present Perfect.

**Rule**: For an interrogative sentence with the 'be going to' future form starting with 'Who', the passive structure is **By whom + is/am/are + object + going to be + V3?** - **Correct Answer (b)**: 'Who' changes to 'By whom'. The object 'the event' is singular, so 'is' is used, followed by the object and the correct passive structure 'going to be managed'. - **Incorrect Answer (a)**: This changes the structure to the 'will' future. - **Incorrect Answer (c)**: This incorrectly changes the tense to the past. - **Incorrect Answer (d)**: 'who' is the incorrect case; 'whom' is required after the preposition 'By'.

**Rule**: For a sentence in the Simple Past Tense, the passive voice structure is **Object + was/were + V3 + by + Subject**. - **Correct Answer (d)**: The object 'the crops' becomes the subject. Since 'crops' is plural, 'were' is used. The adverb 'severely' is correctly placed before the past participle 'damaged'. - **Incorrect Answer (a)**: This incorrectly changes the tense to Simple Present. - **Incorrect Answer (b)**: This incorrectly changes the tense to Past Continuous. - **Incorrect Answer (c)**: This incorrectly changes the tense to Present Perfect.

**Rule**: For an active sentence using 'be going to' with two objects (indirect 'us' and direct 'a test'), either can become the subject in the passive form. - **Correct Answer (d)**: Both (a) and (b) are correct passive transformations. - In (a), the indirect object 'us' becomes the subject 'We'. - In (b), the direct object 'a test' becomes the subject, and the indirect object is expressed as 'to us'. - **Incorrect Answer (a)**: This is correct, but (b) is also a valid transformation. - **Incorrect Answer (b)**: This is correct, but (a) is also a valid transformation. - **Incorrect Answer (c)**: This changes the structure to the 'will' future.

**Rule**: For a Present Continuous Tense sentence, the passive structure is **Object + is/am/are + being + V3 + by + Subject**. - **Correct Answer (d)**: The object 'kites' becomes the subject. Since 'kites' is plural, 'are' is used, followed by 'being' and the past participle 'flown'. - **Incorrect Answer (a)**: This incorrectly changes the tense to Past Continuous. - **Incorrect Answer (b)**: This incorrectly changes the tense to Present Perfect. - **Incorrect Answer (c)**: This incorrectly changes the tense to Simple Present.