单项选择题
A.secure all ventilation
B.shut down the exhaust blowers
C.shut down the intake blowers
D.ventilate the cargo holds
单项选择题 When referring to dry bulk cargoes，the term “flow state”（）.
单项选择题 When measuring the oxygen content of the cargo tanks prior to loading cargoes requiring vapor recovery，check it（）.
单项选择题 When loading bulk liquid cargo，what is the first action you should take if a cargo valve jammed open?（）