单项选择题
A.supply clean air to the measuring compartment of the units for more accuracy
B.generaate the pressure required for the extraction of the oil mist from the
C.generate the pressure required for the extraction of the oil mist from the crankcase
D.supply clean air to the measuring track of the units for more accuracy
单项选择题 In general, the oil mist detectors include a built-in heating unit and a compact plug for electrical connectionThe function of heating unit is to （）
单项选择题 （）continuously extract the crankcase atmosphere, via a pipe system, and move it past a sensitive and accurate opacity measuring track.
单项选择题 The oil mist detectors continuously（） the crankcase atmosphere, via a pipe system, and move it past a sensitive and accurate opacity measuring track.