单选题The lowest temperature at which a liquid gives off enough vapor to ignite in the presence of an ignition source is called its （）.A boiling pointB flash pointC viscosity pointD toxic point

The engine______smoke and steam．

A.gives up

B.gives away

C.gives in

D.gives off

The temperature of the refrigerant in the evaporator coil depends mostly upon the ___.

A.refrigerant pressure in the evaporator

B.cooling water temperature to the condenser

C.heat load in the refrigerator compartment

D.solenoid valve in the liquid line

A、the faster

B、faster

C、the slower

The（auto）ignition temperature is that temperature at which ______．

A.No spark or flame is required to ignite gas or vapor

B.A fuel begins to give off explosive vapors

C.A fuel if ignited will continue to burn

D.A 1% mixture of the fuel with air will explode

Sub-cooling is a method of reducing the temperature of the liquid refrigerant below its ______.

A.freezing point

B.floc point(浊点)

C.condensing temperature

D.compression temperature

A.flash point

B.fire point

C.upper explosive limit

D.lower explosive hmlt

When the fuel oil is burning in the combustion chamber, it _____.

A.gives up large amount of heat

B.gives off large amount of heat

C.gives up large amount of steam

D.gives off large amount of steam

The higher the temperature,()the liquid evaporates.

A. the faster

B. faster

C. the slower

The flash point of a liquid refers to the temperature ______.

A.at which a liquid will give off inflammable（易燃的） vapors

B.at which a liquid will burn steadily

C.at which a liquid will explode

D.that a liquid must reach before it will flow readily

Reid vapor pressure is ______．

A.exerted by liquid cargo on the sides of a tank

B.exerted by liquid cargo on a cargo hose body

C.the lowest temperature and pressure that will cause a flammable liquid to give off vapors

D.a measurement of the amount of flammable vapors given off by a liquid at a certain temperature