According to the story, the game of chess was invented by an ______.

A．how cruel the king was
B．how clever the minister Sissa was
C．Sissa was a famous mathematician
D．how the game of chess came into being

A．The Euro is the only money used in the EU now.
B．Chinese has become an official language in Europe.
C．An increasing number of Chinese tend to travel to Europe.
D．It is always necessary to unite many countries into one,