短語詞組短語underground cavern group 地下洞室群large cavern group 大型洞室群a huge underground cavern group 大型地下洞室群large -scale underground cavern group 大型地下洞室群a large -scale underground cavern group 大型地下洞群large group -cavern 大型洞群group -cavern excavation 洞群開挖 返回 cavern group