CIDR地址块掩码的点分十进制为（）。 ["255.255.252.0","255.255.248.0","255.255.240.0","255.255.224.0"]
不合理信念的特点包括（）。 ["理解性要求","部分概括","心中有爱","固执己见"]
突发事件处理对策的基本要素是（） ["突发事件预警","突发事件处理","突发事件确认","突发事件解决"]
When a vessel is inclined by an external force，the（）. ["shape of the vessel's underwater hull remains the same","vessel's center of gravity shifts to the center of the vessel's underwater hull","vessel's center of buoyancy shifts to the center of the vessel's underwater hull","vessel's mean draft increase"]
重大突发事件发生时应做到（） ["准确迅捷的信息传递","及时的信息确认","科学地理解信息以及据此信息作出的迅速反应"]
怎样对电梯进行维护保养？
