单项选择题
After extinguishing a fire with C02,it is availabe to（）.
A.use all CO2 available to cool the surronding area B.stand by with water or other agents C.thoroughly ventilate the space of CO2 D.jettison all buring materials
单项选择题 After putting on a self-contained breathing apparatus, you open the air supply and hear a continuous ringing of a bell.What does this mean?（）.
单项选择题 After using a C02 portable extinguisher,it should be（）.
单项选择题 All dunnage planks and mats must be sent to board（）commencement of loading.
