On a hydrocarbon flammability chart the line which extends from 0% to 21.8% oxygen，lying tangent to the flammability range，is called the（）.

单项选择题If，during helicopter refueling operations，fuel is spilled on clothing，the person should first（）.

A.see the medic immediately
B.spray himself with foam or CO₂
C.complete his task and then see the medic
D.remove the clothing and wash

单项选择题Each part of the fire-main system located on an exposed deck must be（）.

A.protected against freezing
B.locked to prevent theft
C.numbered sequentially
D.pressurized at all times

单项选择题Each hose in the fuel transfer system for helicopter refueling must meet the standards of the（）.

A.Federal Aviation Administration
B.Corps of Engineers
C.National Fire Protection Association
D.National Transportation Safety Board

单项选择题Each hand portable fire extinguisher must be marked with（）.

A.the name of the vessel on which it is located
B.the date that it was installed
C.the names of the individuals qualified to use it
D.an identification number

单项选择题Each fireman’s outfit and its spare equipment on a vessel must be stowed（）.

A.in a locked cabinet in the machinery space
B.in an unlocked cabinet in the machinery space
C.in a separate and accessible location
D.at a fire hydrant location