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

A.mimimum oxygen content line
B.critical displacement line
C.critical dilution line
D.upper threshold limit


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1.單項選擇題To determine the pressure and temperature limitations under which LFG is required to be transported on a barge，you should look at the（）.

A.Certificate of Inspection
B.loading order
C.rules and regulations for tankers
D.tankerman's document

3.單項選擇題The tops of vents from gasoline tanks should terminate（）.

A.in open air
B.inside cabins
C.in machinery space
D.underwater

4.單項選擇題Gasoline tanks should be filled（）.

A.to the top to expel all vapors from the tanks
B.to the top so the operator is certain how much fuel he has aboard
C.with only sufficient fuel for the planned trip so excess gasoline is not carried
D.to near the top with some space allowed for gasoline expansion

5.單項選擇題When fueling has been completed（）.

A.the fuel tank fill pipe should be left open to allow vapors to vent from the tank
B.the engine should be started immediately to prevent vapor lock in the fuel line
C.all hatches should be opened and all compartments should be ventilated
D.open the fuel line and drain a small amount of gasoline into the bilge to clear the line of sediment

6.單項選擇題The weight of liquefied petroleum gas vapors as compared to air is（）.

A.variable
B.the same
C.lighter
D.heavier

7.單項選擇題Compared to the amount of concentrated foam liquid used，the amount of low expansion mechanical foam produced is（）.

A.97 times greater
B.94 times greater
C.10 times greater
D.2 times greater

8.單項選擇題Where should the tops of vents from gasoline tanks terminate?（）.

A.In open air
B.Inside cabins near the overhead
C.In the machinery space near the engine air intake
D.Underwater

9.單項選擇題One of the principal dangers inherent in liquefied petroleum gas is（）.

A.as it warms up it becomes heavier than air
B.the way it reacts with sea water
C.the strong odor it produces
D.its low temperature causes frostbite or freezing

10.單項選擇題The shut off valve at the gasoline tank which can be operated from outside the tank space （）.

A.controls the amount of gasoline to the engine
B.shuts off the gasoline supply at the tank
C.is used if the gasoline tank leaks
D.All of the above