单项选择题
A.filled with bilge water
B.filled with oil
C.filled with clean water
D.be emptied
单项选择题 The time of discharging oil is short, but oily water separator discharges oil frequentlyThe possible reason is （）
单项选择题 The pressure difference of the gauge on the oily water separator increases greatly, the reason is（）
单项选择题 Oily water separator mis-alarms, the most possible reason is （）