The spread of fire is prevented by（）.

A.shutting off the oxygen supply
B.cooling surfaces adjacent to the fire
C.removing combustibles from the endangered area
D.removing smoke and toxic gases by ensuring adequate ventilation

A.painted red and labeled
B.concealed from the crew
C.protected by plexiglass
D.padlocked

A.the name of the person conducting the test
B.the weight of the charge
C.recommendations for the next test
D.All of the above