--I want to write __________ article about the great inventors in the world. Can you help me? 

--Sorry, I don’t know much about __________ topic.

A．an; a

B．an; the

C．the; a

D．the; the

以下属于行政征收内容的是( )。

A．个人所得税

B．排污费

C．机场建设费

D．电费