单项选择题
Lube oil filters remove contaminants more efficiently if the oil being filtered is （）.
A.under high pressure B.under low pressure C.heated to reduce viscosity D.cooled to increase viscosity
单项选择题 Proper filtering and straining of fuel oil is important because the （）.
单项选择题 An automated diesel engine should normally shut down due to （）
单项选择题 The minimum speed an engine must attain before ignition can occur depends upon （）.
