7，13，39，61，103，( )A．141 B．164 C．185 D．193

—Did you go to Ann's birthday party?

—No, I __________. [ ]

A. didn't invite

B. wasn't inviting

C. hadn't invited

D. wasn't invited

简述叶伯和？

简述新闻导语、主体和结尾的写作要求。

位错密度

常用的交流发电机有几种？