【名词&注释】
局域网(lan)、通信网(communication network)、电话网(telephone network)、文档资料(document information)、实质上(in essence)、帧中继网络(frame relay network)
[单选题]The approaching 4G mobile communication systems are projected to ( ) still remaining problems of 3G systems and to provide ( ) new services ,from high-quality voice to high-definition video to high data-rate wireless channels.[1分]
A. solve
B. solving
C. reduce
D. increase