Convert the sentence provided below from its passive voice structure to an active voice structure: The machinery was known to have been operated manually during the testing phase.
Show answer & explanation
Correct answer: D
Explanation
Given passive sentence:
“The machinery was known to have been operated manually during the testing phase.”
Step 1: Identify structure
This is a passive reporting structure:
Subject + was known + to have been + past participle.
Step 2: Convert to active form
Rule:
Passive reporting verbs like “was known to…” are converted into:
It is known that + subject + verb.
So,
“The machinery was known to have been operated manually…”
becomes
“It is known that someone manually operated the machinery…”
Option Analysis:
Manual operators were known to test the machinery. — Incorrect meaning (testing vs operating).
Someone was known to operate the machinery manually during testing. — Structure incorrect; tense and meaning mismatch.
It was known that the machinery had been manually tested. — Still passive; not active voice.
It is known that someone manually operated the machinery during testing. — Correct active transformation.
Hence, the correct answer is:
It is known that someone manually operated the machinery during testing.