听力文本

Many of these crystals were made of gypsum, a mineral that comes from limestone,
许多结晶都是由石膏组成，一种硫酸钙沉积而来的矿物，
and there was mile after mile of them.
它们绵延不绝
Water is the creator of most caves, but unlike all other limestone caves,
水是大部分洞穴的建造者，但是和其它石灰岩溶洞不同的是
Lechuguilla's rock had not been eaten away by running rainwater. Something else was responsible.
龙舌兰洞中的岩石并非被流水侵蚀。而是因为其它的作用力。
The only water Lechuguilla has are these wonderfully still, clear pools.
龙舌兰洞中唯一的水来自这些平静清澈的水塘

As the explorers went deeper into the cave,
随着探险家们深入洞穴
they came across whole galleries filled with the most unusual formations,
他们发现了成片叹为观止的地貌
like these five-metre cones frosted with the most delicate crystals.
例如这些5米高的石锥，上面布满了雪霜一样的松脆结晶
It was Lechuguilla's gypsum crystals that made scientists question how these caverns were formed.
龙舌兰洞的石膏结晶群，使科学家们产生了这个巨洞如何形成的疑问
They discovered that Lechuguilla's limestone had actually been eaten away
他们发现龙舌兰洞的石灰岩，实际上是被硫酸侵蚀的
by sulphuric acid cutting through literally miles of limestone.
凿穿了差不多数英里的石灰岩。

视频及简介

洞穴是不受阳光控制的生物栖息地之一，但这并不意味着那里就不存在野生生物。本集节目将深入洞穴内神秘而永恒的黑暗，探索山洞、洞穴和隧洞中未知的地下世界。