Решение:
Who используется для людей, What — для предметов или действий.
- What works in an office? - Ann's mum.
- Who is she? - A secretary.
- What has worked at a police station? - My dad.
- Who was he? - A police officer.
- Who is your mum? - An accountant.
- Who is your dad? - A bus driver.
Ответ: 1. What; 2. Who; 3. What; 4. Who; 5. Who; 6. Who.