泛滥之谜 15-英语听力

[00:00.01]Ethiopia hosts 80% of Africa's highest mountains [00:04.50]A legacy of the region's volcanic past. [00:07.96]30 million years ago [00:10.06]A huge plug of molten volcanic rock welled up through cracks in the Earth's crust [00:16.05]Then cooled and solidified to form the Ethiopian Highlands. [00:21.00]Since then, erosion has carved the edges of this rocky dome to spectacular effect. [00:27.99]And there is a surprise up here. [00:30.36]In this arid land, a lake. [00:33.68]At nearly 2,000 metres, Tana is Africa's highest. [00:39.48]Tana's hippos live at a higher elevation than any other. [00:43.62]Could Lake Tana be the elusive source of the Nile's great flood? [00:48.33]The mere trickle flowing out of it doesn't look promising. [00:51.98]But the rocks here tell a different story. [00:55.29]Only a raging torrent could have carved these shapes.