The leaves are _________ the tree.[ ]
A. on
B. in
C. at
答案:A
8253内部寄存器地址的I/0端口中,有多少个是定时/计数通道端口?
固定网短消息中心接通率≥百分之多少?()
A.93%
B.94%
C.95%
D.96%