使用空气呼吸器工作时有什么要求?
参考答案:
(1)使用空气呼吸器工作时,未离开毒区不准脱下面罩;
(2)当空气瓶压力小于5Mpa或报警时,应冷静退出有毒区,更换气瓶。
_______ a dark night, they took the sick boy to the hospital. And after an hour’s curing, the boy was out of danger very soon.
A.With
B.At
C.On
D.In
(2)国际社会主义转入低潮这一事实能够否定社会主义必然代替资本主义这一结论吗