Let's clarify the correct forms for each of the sentences provided:

1. We asked her whether **she was** married.
Nathan asked me how long **I had studied** English.

2. a. He didn’t say where **he was** going.
Ask him where **Helen is**.

3. b. I forgot where **I put** it.
I don’t know where **he lives**.

4. c. He asked me when **I would** return.
Brooke asked me where **I was** going.

5. d. I asked him what time **he could** meet us.
The supervisor asked me why **I was** late for work.

Feel free to ask if you need further assistance!