泛滥之谜 21-英语听力

[00:00.01]The rain-sodden earth can hold no more water. [00:02.80]It spills out across the mountainsides, creating a host of tiny streams. [00:07.42]As they merge, the cargo of fertile soil driven downstream increases. [00:13.12]Streams become rivers. [00:15.26]Finally these rivers flow into the mountain bowl that is Lake Tana. [00:20.53]The lake is filling up all the while, creating marshland on its shores. [00:25.15]Here, weaver birds turn the flower heads of papyrus into building material [00:30.42]and they set about constructing a woven city over the growing lake. [00:34.96]Papyrus is one of the Niles great gifts. [00:38.21]Growing along much of the river's length [00:39.99]it provides a strong waterproof building material [00:42.38]for expert craftsmen such as these. [00:44.99]The people of the Nile have also found it useful for building. [00:49.30]The Ancient Egyptians even used it to make the paper [00:52.40]on which they recorded the story of their great civilisation.