Choose the correct passive voice: "The airline had already boarded the passengers when the delay was announced."
- A. The passengers were already boarded by the airline when the delay was announced.
- B. The passengers have already been boarded by the airline when the delay was announced.
- C. The passengers had already being boarded by the airline when the delay was announced.
- D. The passengers had already been boarded by the airline when the delay was announced. ✓
Correct answer
D. The passengers had already been boarded by the airline when the delay was announced.
Explanation
Past perfect active becomes past perfect passive: 'had already been boarded'.