求翻译：There was great public interest when a big hole mysteriously appeared in the middle of a field. Army mechanics and engineers were called in to explain how it had got there. They offered various explanations but were not at all sure how the hole had been caused. It was thought that a large shell which must have lain bur是什么意思？

待解决 悬赏分：1 - 离问题结束还有