是一种多层、连续型、可变长度的条码符号，它可以表示全部的128个ASCII字符（）
A. CodeOne
B. QRCode
Code49
DataMatrix
物业服务企业员工住房公积金和社会保险费的计提比例，应当按照()的比例确定。
A. 业主大会同意
B. 当地政府规定
C. 职工大会商定
D. 企业核定
在磁脉冲测速装置中，为了检测船舶主机的转向，需要装有两个磁脉冲传感器，且它们之间在相位上要相差（）个周期。
A. 1/2
B. 1/3
C. 1/4
D. 1/5
Which statement is true about the command ipv6 ospf 1 area 0?（）
A. It must be issued before the network command to enable the OSPF pr ocess for IPv6.
B. It must be issued after the network command to enable the OSPF process for IPv6.
C. It must be issued in router global configuration mode to enable the OSPF process for IPv6.
D. It must be issued in interface configuration mode to ena ble the OSPF process for IPv6.
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