钙矽卡岩：
参考答案：
石榴石、透辉石-钙铁辉石、硅灰石、方柱石、（白钨矿）等。
What_____just now?
A．did he happen
B．did happen to him
C．happen to him
D．happened to him
某校园网的地址是202.100.192.0/16，要把该网络分成30个子网，则子网掩码应该是______。
A) 255.255.200.2 B) 255.255.224.0 C) 255.255.254.1 D) 255.255.248.0
