纪录片《我们的地球》 第65期 洞穴迷宫(04)（在线收听）

The limestone towers of Vietnam's Halong Bay are a reminder of this link with the sea.

越南下龙湾的石林能说明石灰岩与海洋的关系

Originally this whole area would have been one solid block of limestone, the base of a coral reef.

起初，这整个地方都是一整块坚固的石灰岩床，珊瑚礁的基座

In Borneo, rain has sculpted the limestone into extremely sharp-sided pinnacles.

在婆罗洲，雨水已将石灰岩雕凿成无比尖削的石塔

But the dissolving power of rainwater has other, much more dramatic, effects underground.

不过在地下，雨水的溶解作用还能产生其它更壮观的效果

Rivers that flow over limestone often seem to completely disappear.

流经石灰岩的河川到最后似乎总是无影无踪

When the water reaches a more resistant bed of limestone, its course is altered.

当水流遇到更坚硬的石灰岩床时，就会改变路线。

Once underground, the water takes on a new, more erosive power.

一旦进入地下，水便有了一股新的、更强的侵蚀力。

During its journey from the surface, the water absorbed carbon dioxide from the soil, making it mildly acidic.

在地面上流淌时，水从土壤中吸收了二氧化碳，成为弱酸性。

And over millions of years, this acid eats away the limestone,

石灰岩经过几百万年的酸蚀作用

creating a maze of caverns and passages that sometimes go on for miles.

形成了迷宫般的溶洞和通道，有的甚至深达数英里。