Transforming Active Past Perfect to Passive Voice

The task is to convert the given active voice sentence, "He had lost the keys before the meeting," into its correct passive voice form. This involves understanding how tenses change when moving from active to passive voice, specifically focusing on the Past Perfect Tense.

Analyzing the Active Sentence Structure

The original sentence is in the active voice:

• Subject: He
• Verb Phrase: had lost (This indicates the Past Perfect Tense)
• Object: the keys
• Adverbial Phrase: before the meeting

The Past Perfect Tense describes an action that was completed before another action or point in the past.

Key Rules for Past Perfect Passive Conversion

To transform a sentence from the Active voice (Past Perfect Tense) to the Passive voice, follow these steps:

• The object of the active sentence becomes the subject of the passive sentence. In this case, 'the keys' becomes the new subject.
• The verb needs to be changed. For the Past Perfect Passive, the structure is: 'had been' + past participle of the main verb. The past participle of 'lose' is 'lost'. So, the verb phrase becomes 'had been lost'.
• The subject of the active sentence ('He') becomes the object of the preposition 'by' in the passive sentence ('by him'). This part is optional but often included for clarity.
• Any additional phrases, like time expressions ('before the meeting'), are retained in their appropriate place.

The general formula for Past Perfect Passive is: Object + had been + Past Participle + (by + Subject) + Adverbial Phrase.

Applying the Conversion Steps

Applying these rules to the sentence "He had lost the keys before the meeting":

• Start with the object: The keys
• Add the Past Perfect Passive verb form: had been lost
• Add the agent (optional but present here): by him
• Add the remaining phrase: before the meeting

This results in the passive sentence: "The keys had been lost by him before the meeting."

Evaluating the Provided Options

Let's check why Option 3 is the correct choice:

• Option 1: "The keys had lost before the meeting." - Incorrect. It lacks the auxiliary verb 'been', which is essential for the passive form of the Past Perfect Tense.
• Option 2: "The keys has been lost." - Incorrect. It incorrectly uses 'has been' instead of 'had been'. The tense should remain Past Perfect. It also omits the time phrase.
• Option 3: "The keys had been lost by him before the meeting." - Correct. This perfectly matches the required structure: Subject ('The keys') + 'had been lost' (verb) + 'by him' (agent) + 'before the meeting' (adverbial phrase).
• Option 4: "The keys were lost by him." - Incorrect. This sentence uses the Past Simple Passive ('were lost'), not the Past Perfect Passive required by the original sentence.

Therefore, Option 3 accurately transforms the original active sentence into the passive voice while maintaining the Past Perfect Tense.