砌块砌体的竖缝宽度超过3Cm时，要灌（）。 ["水泥砂浆","高标号水泥砂浆","混合砂浆","细豆石混凝土"]
Which of the following are true of both OSPFv2 and OSPFv3?（） [" The method of choosing an OSPF router ID"," Verification checks that must be validated before two routers can become OSPF neighbors"," Support for route tags"," Support for multiple instances per inter face"]
关于保温层施工，哪项叙述不正确？（） ["当保温层厚度超过150mm时，应分为两层或多层逐层施工，便于施工，减少热损失","保温棉毡、垫的保温厚度和密度应均匀，外形应规整，密度应符合设计要求","各种支架及设备的保温应按热伸长方向留出伸缩缝，以防热胀冷缩时破坏保温。保温结构不得妨碍支架的滑动和设备的正常运行","管道端部或有盲板的部位应敷设保温层"]
在数控车床上加工时，如刀尖安装高度高时对工作角度的影响是（）。 ["前角变大","前角变小","后角变大","后角变小"]
对一个B类网段进行子网划分，子网掩码是19位。每个子网能够容纳的最大的主机数（） ["254","1022","8192","8190"]
简述母公司对子公司控制的主要手段。
