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
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相关考题
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单项选择题
All of the following are part of the fire triangle EXCEPT （）.
A.fuel
B.oxygen
C.heat
D.electricity -
单项选择题
The vapors given off by heated fuel oil are heavier than air and are（）.
A.odorless
B.explosive
C.nontoxic
D.visible -
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?（）
A.Pump only if the discharge is led to a shore tank or barge
B.Pump only during the hours of darkness
C.Pump only on the outgoing tide
D.Pump only as much as is necessary
