After an explosion,repair of emergency machinery and services should be accomplished().
A. after control of fire,flooding,and structural repairs
B. immediately,before the emergency is under control
C. after control of fire,but before control of flooding
D. after stability is restored
查看答案
装有254×254密封制动缸活塞行程(有闸调器)重车位为()。
A. 115~135mm
B. 115~160mm
C. 130~150mm
D. 130~160mm
若要求水平角观测6个测回,则下列哪些值可能为配置度盘数()
A. 0度
B. 30度
C. 60度
D. 180度
Rh阴性的妇女怀孕Rh阳性的胎儿,产后需要输血时为何不能接受Rh阳性人的血?