1. Our lessons usually last (two hours).
Общий:
Do our lessons usually last two hours?
Специальный:
How long do our lessons usually last?
К подлежащему:
What usually lasts two hours?
Альтернативный:
Do our lessons usually last two hours or three ours?
Разделительный:
Our lessons usually last two hours, don't they?
2. (The station) was not far away.
Общий:
Wasn't this station far away?
Специальный:
Where was this station?
К подлежащему:
What wasn't far away?
Альтернативный:
Wasn't this station or the bus stop far away?
Разделительный:
The station was not far away, was it?
3. He had been intoduced to me (before I met you).
Общий:
Had he been intoduced to me before I met you?
Специальный:
Why had he been intoduced to me before I met you?
К подлежащему:
Who had been intoduced to me before I met you?
Альтернативный:
Had he been intoduced to me before I met you or had she?
Разделительный:
He had been intoduced to me before I met you, hadn't he?