and one of the greatest sights is in Virginia and Kentucky where the rock under the ground is all limestone.  而最美丽的风景之一是在弗吉尼亚州和肯塔基州，那里地下的石头全都是石灰岩。

The “sights” are huge caves, and in Kentucky they are so large they are called Mammoth Caves.  “风景”就是巨大的山洞，在肯塔基州有些山洞非常大，叫做“猛犸洞”。

These caves have not been dug out by men but by water. Water, you know, melts sugar;  这些山洞不是由人工开凿的，而是由于水的作用形成的。你知道，水可以溶解糖；

but perhaps you didn’t know that water melts rock too—not ordinary rock, but it melts limestone, and these caves are in limestone rock.  但是你也许不知道水也能溶解岩石——不是普通的岩石，而是石灰岩，这些山洞正是处在石灰岩中。

The Mammoth Cave is like a huge cellar underground—a cave so large and high that you could put a whole city with its tall buildings in it.  猛犸洞就像是地下一个巨大的地窖——又大又高，以至于你可以把整个城市连同它的高楼大厦一起放进去。

You could easily get lost and wander for miles.  你在里面很容易就会迷路，漫无目的地走上几英里。

Men have been lost and unable to find their way out again and died and their skeletons have been found long years after. 有人在里面走失过，无法找到出来的路，于是死在里面，他们的骸骨多年以后才被人发现。

Through the roof of the cave water drips drop by drop, and each drop leaves a bit of limestone,  水从岩洞顶部一滴一滴往下滴，每一滴水都会留下一点石灰岩，

until in the course of time the dripping water makes icicles of rock that hang down from the roof of the cave.  时间久了水滴就慢慢形成了倒挂在洞顶的石柱。

Drops of water from each icicle fall on to the floor of the cave,  水沿着石柱滴到岩洞的地面上，留下的石灰岩逐渐堆积起来，

and the limestone gradually piles up and up like a stone post until at last the icicle above meets the post beneath.  也形成石柱，直到上下石柱最后会合在一起。

The trickling water also forms pools in the bottom of the cave,  滴下的水还会在洞底形成小水池，

and in these pools of water live fish that are different from the fish in the water above ground.  里面生长着一种与众不同的鱼。

As it is pitch dark in the caves, these fish have no use for their eyes, so after long, long years they at last grew none.  由于洞里是漆黑的，这些鱼不需要用眼睛看东西，久而久之它们就不长眼睛了。

They are blind. Instead of seeing, they feel with the part of their heads where their eyes were. 它们看不见东西。它们不用眼睛，而是用头上原来长眼睛的地方去感觉。