1. I had been working for an hour when he came.

• I hadn't been working for an hour when he came.
• Had I been working for an hour when he came?

    2. We had been searching for a room for two hours before we found a free one.

• We had not been searching for a room for two hours before we found a free one.
• Had we been searching for a room for two hours before we found a free one?

    3. I had been waiting for them all morning, so I felt annoyed.

• I had not been waiting for them all morning, so I didn’t feel annoyed.
• Had she been waiting for them all morning, so she felt annoyed?

    4. She’d been driving a car for an hour before she came to the gas station.

• She hadn’t been driving a car for an hour before she came to the gas station.
• Had she been driving a car for an hour before she came to the gas station?

     5. She had been running for two hours before she saw a village.

• She had not been running for two hours before she saw a village.
• Had she been running for two hours before she saw a village?