1) Отрицательное предложение Last spring the flood did not destroy half of the town.
2) Альтернативный вопрос Did the flood destroy half of the town last spring or last autumn?
3) Специальный вопрос When did the flood destroy half of the town?
4) Вопрос к подлежащему What destroyed half of the town last spring?
5) Отрицательный вопрос Didn't the flood destroy half of the town last spring?
6) Разделительный вопрос Last spring the flood destroyed half of the town, didn't it?