GSM系统的BSS部分包含以下（）网络实体。
A.HLR、VLR、MSC
B.HLR、VLR、TC
C.BSBTS、TC
D.OMC_R
参考答案：C
She speaks English fluently _____ she were a native American.
A．as though
B．even if
C．as long as
D．ever since
三氟甲烷和一氯三氟甲烷的混合物
