They found two ruined buildings. Общий вопрос: Did they find two ruined buildings? Специальный вопрос: What did they find? Вопрос к подлежащему: Who found two ruined buildings? Альтернативный вопрос: Did they find two or three ruined buildings? Разделительный вопрос: They found two ruined buildings, didn't they? Типы вопросов выберите сами.