单项选择题
A.Commence draining that tank as quickly as possible
B.Seal off all vents to that tank
C.Activate the CO2 system to that tank
D.Shut off the steam heating coils
单项选择题 The FIRST course of action in fighting a fire in a cargo or fuel oil tank is to （）.
单项选择题 In fighting a fire in a fuel tank, the FIRST action you should attempt is to （）.
单项选择题 Which of the following conditions is true concerning a flammable liquid with a concentration above the upper explosive limit?（）