单项选择题
A.Cast iron B.Cast steel C.Forged steel D.Aluminum
（） of the A-frames there is a strong cast iron frame ca...
单项选择题（） of the A-frames there is a strong cast iron frame called the scavenging air box.
A.At the top B.At the bottom C.In the top D.In the bottom
（） of an engine crankshaft can be detected by measuring...
单项选择题（） of an engine crankshaft can be detected by measuring deflections of crank webs for each unit of the engine.
A.Misalignment B.Length C.Strength D.Stresses
（） may be the first possible cause which makes the engi...
单项选择题（） may be the first possible cause which makes the engine to lose power or slow down when it is running.
A.Hot bearing B.Starting valves C.Unequal distribution of load D.Excessive crankshaft clearance
