Verified answer

My working day began at 7 o’clock, didn’t it? Разделительный

Did your working day begin at 7 o’clock ? Общий

Did your working day begin at 7 or 8 o’clock? Альтернативный

When did your working day begin? Специальный

What began at 7 o’clock? Вопрос к подлежащему