开关箱中漏电保护器的额定漏电动作时间不应大于0.1秒。
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Which of the following characteristics describe the Root Guard feature？（Choose all that apply.）（）
A. The port must be put into forwarding state manually after root-inconsistent state has beencorrected
B. A Root Guard port receiving superior BPDU goes into a root-inconsistent state
C. A Root Guard port receiving inferior BPDU goes into a root-inconsistent state
D. While the port is in a root-inconsistent state no user data is sent across that port
E. The port returns to a forwarding state if inferior BPDUs stop
F. It should be applied to all switch port
()DB11/418《电梯日常维护保养规则》标准规定,电梯施工单位负责人对使用单位的电梯安全全面负责。
A. 正确
B. 错误
（）的定义，是设备能分辨单根实芯镀锡铜线的能力，一般用线的标称直径（mm）和线号（AWG）表示
A. 穿透力
B. 线分辨力
C. 通过率
D. 灰度分辨力
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