1.общий
Наd Mary returned by 10 o'clock yesterday?
2.альтернативный
Наd Mary returned by 10 or 7 o'clock yesterday?
3.к подлежащему
Who had returned by 10 o'clock yesterday?
4.специальный
Why наd Mary returned by 10 o'clock yesterday?
5.разделительный
Mary had returned by 10 o'clock yesterday, hadn't she ?