单项选择题
Diesel fuel vapors （）.
A.can not be ignited by a spark unless the vapor is in a confined space B.are nontoxic in all concentrations C.can not be ignited by a spark unless they are at their auto-ignition temperature D.are heavier than air
单项选择题 All of the following are part of the fire triangle EXCEPT （）.
单项选择题 The vapors given off by heated fuel oil are heavier than air and are（）.
单项选择题 If it becomes necessary to pump bilges while a vessel is in port, which of the following procedures should be followed?（）
