HINTS： 

50 kilometres

Alexandria

Eratosthenes

"Beta", 

Greek alphabet, 

"Alpha".

Great Library of Alexandria.

papyrus 

It is about 50 kilometres west of what was once one of the great cities of the world, Alexandria. In Alexandria at that time, there lived a man named Eratosthenes. One of his envious contemporaries called him "Beta", the second letter of Greek alphabet, because he said Eratosthenes was second best in the world in everything. But it seems clear that in many fields, Eratosthenes was "Alpha". He was an astronomer, historian, geographer, philosopher, poet, theater critic and mathematician. He was also the chief librarian at the Great Library of Alexandria. And one day while reading a papyrus book in the library, he came upon a curious account.

这篇材料你能听出多少？点击这里做听写，提高外语水平>>