If the flame from combustion in the cylinder of a four-stroke engine past the piston into

A steady flame in a gas range is the result of ______.

A．a burning velocity equal to the combustion wave

B．fuel being supplied at the same rate as the combustion wave

C．fuel being supplied at a higher rate than that of burning velocity

D．a free flowing supply of air from the openings in the head of the burner

Flame screens are used to ______.

A.contain flammable fumes

B.protect firefightiers from flames

C.prevent flames from entering tanks

D.keep flame and sparks from getting out of an engine’s exhaust system

A flame screen ______.

A.permits the passage of vapor but not of flame

B.prevents the passage of flammable vapor

C.prevents inert gas from leaving a tank

D.permits vapors to exit but not enter a tank

A、skiing

B、under the water

C、via satellite

D、by dragon boat

As can be seen from the passage, Carry the Flame ______.

A．was founded by Mr. Cavelier, a Vietnam veteran

B．members come from all over the country

C．riders are also members of Rolling Thunder

D．hold the flame-lighting ceremony once a year

Flame failure in an automatically fired auxiliary boiler can from a/an _________.

A.incorrect electrode setting

B.incorrect nozzle position

C.clogged fuel nozzle

D.broken high tension lead

composes and from _______

A.petroleum crystals

B.phosgene gas

C.water vapor

D.carbon monoxide

e listed refrigerants will break down and produce phosgene gas？

A.CO2

B.Methyl chloride

C.R-22

D.Sulphur dioxide

l ___.

A.change from blue to orange

B.‘flare up’ and remain lighted

C.probably go out

D.stay blue

A、The long pipe keeps your hand away from the flame so you never get burned.

B、The safety catch makes it easy to operate.

C、You don’t have to worry about children playing with it.

D、The color is attractive to children.

n the sea, the last bather comes up from the beach, children straggle home, dark little figures etched against the sky; lights shine in the houses, and each household gathers for its evening meal.

A、sight

B、taste

C、smell

D、touch

E、hearing