预制灭火系统、柜式气体灭火装置喷嘴前（）内不得有阻碍气体释放的障碍物。
A.1.0m
B.1.5m
C.2.0m
D.2.5m
参考答案：C
He________an engineer by an oil company in the Middle East.
A．was employed as
B．employed as
C．was employed for
D．employed
如果一个人走路摇晃，站立不稳，动作不协调，头脑可能发生病变的部位是______．
