Having finished lunch, the case was discussed.

A．they discussed the case

B．they had discussed the case

C．the case was discussed

D．the case had been discussed

汉字国标码(GB2312—1980)将汉字分成( )。

A．一级汉字和二级汉字2个等级
B．一级、二级、三级3个等级
C．简体字和繁体字2个等级
D．常见字和罕见字2个等级