Ответ:
1) Общий вопрос (General question)
Had the boy been dancing for an hour when Mr Garrett came home?
2) Специальный вопрос (Wh-question)
What had the boy been doing for an hour when Mr Garrett came home?
3) Альтернативный вопрос (Alternative question)
Had the boy been dancing for an hour or watching film?
4) Разделительный вопрос (Tag question)
The boy had been dancing for an hour, hadn't he?
Объяснение: