单项选择题 To start the ejection process the oil feed to the centrifuge is first shut off and the oil remaining in the bowl removed by admitting （）.

单项选择题 To prevent the build up of high stresses engine must not be run continuously （）.

单项选择题 To counteract these undesirable effects cylinder oils usually contain additives formulated to impart a high degree of （） and detergency.