载客甲板的栏杆的高度应不小于()m,亦不高于1.2m。载客甲板的栏杆的最低一档以下的开口,应不超过()m,其他各档间距应不超过()m,直杆距离应不大于2.5m。
A. 0.8;0.23;0.38
B. 0.9;0.23;0.38
C. 0.8;0.25;0.35
D. 0.9;0.25;0.25
WCDMAFDD信号调制方式是上行采用QPSK,下行采用BPSK。
A. 正确
B. 错误
In a switched environment, what does the IEEE 802.1Q standard describe?()
A. the operation of VTP
B. a method of VLAN trunking
C. an approach to wireless LAN communication
D. the process for root bridge selection
E. VLAN pruning vla