单项选择题
A.close the vent
B.pump out the tank
C.activate the fixed CO2 system
D.cut off the heating coils
单项选择题 Any friction fit, tightness or adhesion of the part of any load being lifted should be broken by wedge or tapping and not by increasing the load on the applianceAccording to this sentence, （）
单项选择题 In order to remove the carbon deposit from the threaded recess, we can use（）
单项选择题 Waste oil should（）