泛滥之谜 24-英语听力

[00:00.01]More than 60 mountain rivers have flowed into Lake Tana [00:04.63]But only one river flows out, the Blue Nile. [00:11.32]Virtually dry just a few months ago [00:14.68]It has now become a very different river. [00:18.65]The highlanders call these falls Tis Lsat. [00:22.35]It means ''smoking fire''. [00:28.95]This, surely, is a force powerful enough [00:31.47]to carry the great flood thousands of kilometres to the deserts of Egypt. [00:38.37]Gathering speed and power, the floodwaters sweep on into the Blue Nile Gorge. [00:43.94]Well over a thousand metres deep [00:46.40]nearly 20 kilometres wide and over 600 kilometres long [00:50.48]this is Africa's Grand Canyon. [00:53.24]From all over the highlands, other huge rivers pour into the Blue Nile Gorge. [00:57.89]By the time it leaves Ethiopia [00:59.96]the Blue Nile will be 50 times the size it was in the dry season. [01:04.73]Now the Blue Nile is carrying 140 million tonnes of fertile soil. [01:10.87]For a million years [01:12.00]the Blue Nile has been carving this huge gash through the Ethiopian Highlands [01:16.28]grinding down the volcanic rock, grain by grain, to form the enormous gorge.