單項(xiàng)選擇題

If there has been a fire in a closed unventilated compartment it may be unsafe to enter because of （）.

A.unburned carbon particles
B.excess nitrogen
C.a lack of oxygen
D.excess hydrogen

你可能感興趣的試題

After a fire has been extinguished in a closed space, personnel may safely enter the space when （）.

A.smoke density has been decreased sufficiently to see the bulkhead opposite the compartments entrance
B.a lifeline and explosion proof flash light are used
C.all smoke and toxic fumes are removed and an adequate oxygen supply is present
D.overhaul has been completed to remove any possible source of re-ignition

單項(xiàng)選擇題

Which of the petroleum products listed has the lowest flash point?（）

A.Hydraulic oil
B.Lubricating oil
C.Diesel oil
D.Refrigeration oil