单项选择题
The rising of the exhaust temperature in manifold pipe may NOT result from （）.
A.too great a loading B.fouled turbocharger C.bad combustion D.excessive air
单项选择题 The rim of the piston may contain cut-out portions to accommodate （） when they open.
单项选择题 The removal of （） from lubricating oil will reduce engine wear and possible breakdowns.
单项选择题 The remaining oil in the lubricating pipes and ducts should be blown out with （）.
