单项选择题
A.the oil feeding is stopped and replaced by admitting flushing water
B.the flushing water feeding is stopped and replaced by admitting oil
C.the feeding of dirty oil and flushing water is stopped
D.the feeding of dirty oil and flushing water is admitted
单项选择题 A centrifuge of which the bowl is arranged as the upper and lower parts separate discharges the sludge（）
单项选择题 “A centrifuge consists of an electric motor driving a vertical shaft on the top of which is mounted the bowl assembly”.According to this sentence, we can know that is mounted on the top of the vertical shaft（）
单项选择题 The treatment of the fuel oils involves storage, heating, filtering and（）