主井罐笼提升的开车信号由井底控制，可以直发提升机房。
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现有两辆试验样车进行30000km可靠性试验，1辆车出现3类以上故障14次，另1辆车出现3类以上故障16次，试计算平均故障间隔里程。
实验教育学的代表人物是（）
A. 梅伊曼、拉伊
B. 狄尔泰、斯普朗格
C. 杜威、克伯屈
D. 鲍尔斯、金蒂斯
产生（）时，切削力波动小，加工表面光洁。
A. 带状切屑
B. 节状切屑
C. 崩碎切屑
D. 粒状切屑
A switch has been configured with two vlans and is connected to a router with a trunk for inter-vlan routing.OSPF has been configured on the router，as the routing protocol for the network.Which statement about thisnetwork is true？（）
A. For the two vlans to communicate，a network statement for the trunk interface needs to be added to the OSPF configuration.
B. For the two vlans to communicate， a network statement for each subinterface needs to be added to the OSPF configuration.
C. Direct inter-vlan communication does not require OSPF
D. OSPF cannot be used if router-on-a-stick is configured on the router
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