单项选择题
A.smoke sensors B.the difference in thermal expansion of two dissimilar metals C.pressure loss due to air being heated D.an electric eye which actuates when smoke interferes with the beam
A.removing the heat B.removing the oxygen C.removing the fuel D.interrupting the chain reaction
A.it is impractical to locate them outside B.there is also a control valve outside C.the CO2 cylinders are also in the space D.an automatic heat-sensing trip is installed