新概念第三册 Lesson 42 Modern cavemen

　　A team of pot-holers recently went down the Gouffre Berger. After entering the narrow gap on the plateau, they climbed down the steep sides of the cave until they came to narrow corridor. They had to edge their way along this, sometimes wading across shallow streams, or swimming across deep pools. Suddenly they came to a waterfall which dropped into an underground lake at the bottom of the cave. They plunged into the lake, and after loading their gear on an inflatable rubber dinghy, let the current carry them to the other side. To protect themselves from the icy water, they had to wear special rubber suits. At the far end of the lake, they came to huge piles of rubble which had been washed up by the water. In this part of the cave, they could hear an insistent booming sound which they found was caused by a small waterspout shooting down into a pool from the roof of the cave. Squeezing through a cleft in the rocks, the pot-holers arrived at an enormous cavern, the size of a huge concert hall. After switching on powerful arc lights, they saw great stalagmites -- some of them over forty feet high -- rising up like tree-trunks to meet the stalactites suspended from the roof. Round about, piles of limestone glistened in all the colours of the rainbow. In the eerie silence of the cavern, the only sound that could be heard was made by water which dripped continuously from the high dome above them.

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