单项选择题
A.oil leakage in engine-room B.hot work (welding, cutting, etc) C.static electricity D.all of the above
A.the three elements of fire and explosion B.lower and upper flammable limits C.classification of flies and applicable extinguishing agents D.All of the above
A.use self-contained breathing apparatus B.use various types of portable fire extinguishers C.effect a rescue in a smoke-filled space wearing breathing apparatus D.All of the above