单项选择题
Large volumes of carbon dioxide are safe and effective for fighting fires in enclosed spaces，such as in a pumproom，provided that the（）.
A.persons in the space wear gas masks B.persons in the space wear damp cloths over their mouths and nostrils C.ventilation system is secured and all persons leave the space D.ventilation system is kept operating
单项选择题 Inflatable liferafts are less maneuverable than lifeboats due to their（）.
单项选择题 In which situation could a vessel most easily capsize?（）
单项选择题 In heavy seas you decide to heave to. The lifeboat should be（）.
