单项选择题
There is a smell of gas in the hold. You must wear your （）(氧气面罩).
A. fire mask B. breathing apparatus C. life-jacket D. fire drill
单项选择题 Prepare for （）(弃货) cargo.
单项选择题 Post two lookouts with （）(望远镜).
单项选择题 Prevent （）(油) overboard
