A.電路交換,電路交換 B.電路交換,分組交換 C.分組交換,電路交換 D.分組交換,分組交換
A.Global Packet Radio Service B.General Packet Radio System C.General Packet Radio Service D.Global Packet Radio System
A.WCDMA B.GSM C.GSM+GPRS D.CDMA