单项选择题
During working, when the piston is near the （）, the air ignites the fine spray of fuel.
A.TDC B.DTC C.BDC D.BCD
单项选择题 During the suction stroke, the piston is moving （）.
单项选择题 During the inspection, the starting air valves should be closed （） the engine from turning.
单项选择题 During repair,lubrication lines and orifices must be （）.
