Choose the correct passive voice: "The engineers were testing the bridge's structural integrity."
- A. The bridge's structural integrity was tested by the engineers.
- B. The bridge's structural integrity has been tested by the engineers.
- C. The bridge's structural integrity is being tested by the engineers.
- D. The bridge's structural integrity was being tested by the engineers. ✓
Correct answer
D. The bridge's structural integrity was being tested by the engineers.
Explanation
Past continuous active becomes past continuous passive: 'was being tested'.