Finding information in today’s world is easy．The      is how you can tell if the information you get is useful or not．

A．ability

B．competition

C．challenge

D．knowledge

下列著名作家中曾经在砖塔胡同附近居住过的有( )。

A．鲁迅

B．巴金

C．张恨水

D．曹禺

E．郭沫若