Which sentence contains a past-perfect-passive error in the form used before a past deadline?
The invitations had been posted before the office closed.
The stage had been cleared before the audience arrived.
The labels had been print before the boxes were sealed.✓Correct answer
The route had been approved before the team departed.
Explanation
The sentence about the labels contains the error because had been must be followed by the participle printed, not print. The invitations sentence demonstrates the complete had been plus participle sequence before another past event.