[al:新概念英语（三）] [ar:MP3 同步字幕版（英音）] [ti:Modern Cavemen] [by:更多学习内容，请到chazidian.com搜索“新概念”] [00:01.46]Lesson 42 [00:03.56]Modern cavemen [00:11.73]With what does the writer compare the Gouffre Berger? [00:18.32]Cave exploration, or pot-holing, as it has come to be known, is a relatively new sport. [00:25.23]Perhaps it is the desire for solitude or the chance of making an unexpected discovery that lures people down to the depths of the earth. [00:35.62]It is impossible to give a satisfactory explanation for a pot-holer's motives. [00:41.30]For him, caves have the same peculiar fascination which high mountains have for the climber. [00:47.84]They arouse instincts which can only be dimly understood. [00:53.15]Exploring really deep caves is not a task for the Sunday afternoon rambler. [00:59.33]Such undertakings require the precise planning and foresight of military operations [01:06.19]It can take as long as eight days to rig up rope ladders and to establish supply bases before a descent can be made into a very deep cave. [01:17.61]Precautions of this sort are necessary, [01:20.72]for it is impossible to foretell the exact nature of the difficulties which will confront the pot-holer. [01:27.95]The deepest known cave in the world is the Gouffre Berger near Grenoble. [01:33.83]It extends to a depth of 3, 723 feet. [01:38.99]This immense chasm has been formed by an underground stream which has tunnelled a course through a flaw in the rocks. [01:47.73]The entrance to the cave is on a plateau in the Dauphine Alps. [01:53.04]As it is only six feet across, it is barely noticeable. [01:57.55]The cave might never have been discovered [01:59.79]had not the entrance been spotted by the distinguished French pot-holer, Berger. [02:05.58]Since its discovery, it has become a sort of pot-holers' Everest. [02:10.62]Though a number of descents have been made, much of it still remains to be explored. [02:16.67]A team of pot-holers recently went down the Gouffre Berger. [02:21.19]After entering the narrow gap on the plateau, [02:24.19]they climbed down the steep sides of the cave until they came to a narrow corridor. [02:30.12]They had to edge their way along this, [02:33.06]sometimes wading across shallow streams, or swimming across deep pools. [02:38.92]Suddenly they came to a waterfall which dropped into an underground lake at the bottom of the cave. [02:46.31]They plunged into the lake, [02:48.28]and after loading their gear on an inflatable rubber dinghy, let the current carry them to the other side. [02:56.96]To protect themselves from the icy water, they had to wear special rubber suits. [03:02.46]At the far end of the lake, they came to huge piles of rubble which had been washed up by the water. [03:08.71]In this part of the cave, they could hear an insistent booming sound [03:13.93]which they found was caused by a small waterspout shooting down into a pool from the roof of the cave. [03:21.03]Squeezing through a cleft in the rocks, [03:23.62]the pot-holers arrived at an enormous cavern, the size of a huge concert hall. [03:30.09]After switching on powerful arc lights, [03:32.69]they saw great stalagmites--some of them over forty feet high--rising up like tree-trunks to meet the stalactites suspended from the roof. [03:43.40]Round about, piles of limestone glistened in all the colours of rainbow. [03:49.04]In the eerie silence of the cavern, [03:51.43]the only sound that could be heard was made by water which dripped continuously from the high dome above them.