单项选择题
When loading or discharging dry mud or cement，crew members should use goggles and（）.
A.facial respirator mask B.ear plugs C.rubberized boots D.fireman's outfit
单项选择题 When collecting condensation for drinking water，（）.
单项选择题 When choosing extinguishers to fight a Class “B” fire do NOT use（）.
单项选择题 What should be used to steer an open lifeboat if the rudder becomes lost or damaged?（）
