单项选择题
A.the filter is clogged
B.bilge suction value is clogged
C.suction value and discharge value of the pump do not open fully
D.screw pump is worn seriously and volumetric efficiency is decreased
单项选择题 Oily water separator mis-alarms, the most possible reason is （）
单项选择题 Because the flow rate of supply water pump is too large, oily water separator does not work wellWhich of the following is not the reason?（）
单项选择题 When starting air-conditioner in the winter, we should open（）in sequence. Ⅰ.alve of warming Ⅱ.alve of humidifier Ⅲ.an