Change the following sentence into the Active form.
The old castle was believed to have been built by a legendary king.
Show answer & explanation
Correct answer: B
Explanation
The original sentence is in the passive voice, with a complex structure: "The old castle was believed (by people - implied subject) to have been built by a legendary king."
To convert this to the active voice, we need to identify the implied subject ("People") and make it the main subject of the sentence. The passive infinitive phrase "to have been built" must also be changed to an active form, which is "had built" to maintain the past perfect tense implied by the context of the belief.
The active subject is "People" (implied in the original passive sentence).
The active verb for the main clause is "believed" (matching "was believed").
The embedded clause must also be active: "a legendary king had built the old castle" (matching "to have been built by a legendary king").
Option (B) correctly implements these changes, resulting in a grammatically correct and meaningful active sentence.