“船员日常防火守则”应是（）。
A．全体船员遵守
B．高级船员遵守
C．普通船员遵守
D．轮机部船员遵守
参考答案：A
I was about to go to bed _____ one of my old classmates made a call to me.
A．when
B．as
C．while
D．that
什么是压力容器的二次爆炸？
