ответ: вопросительная форма
Had he been reading а book since morning when I rang him up?
Отрицательная форма
He hadn't been reading a book since morning when I rang him up
ответ: вопросительная форма
Had he been reading а book since morning when I rang him up?
Отрицательная форма
He hadn't been reading a book since morning when I rang him up