锚栓抗拔承载力现场检验，当非破坏性检验为不合格时，应另抽不少于（）个锚栓做破坏性检验判断。
A、5
B、4
C、3
D、2
参考答案：C
营养不良
Both bus and tree topologies are characterized by the use of multipoint(1)．For the bus,all stations attach,through appropriate hardware(2) known as a tap,directly to a linear transmission medium, or bus. Full-duplex operation between the station and the tap allows data to be transmitted onto the bus and received from the(3).Atransmission from any station propagates the length of the medium in both directions and can be received by all other(4).At each end ofthe bus is a(5),which absorbs any signal, removing it from the bus．
空白（5）处应选择（）
A.tap
B.repeater
C.terminator
D.concentrator
