单项选择题
Friction developing between the moving parts of a governor, governor linkage and control valve will cause the governor to （）.
A.react with insufficient speed droop B.fail to react to small speed changes C.have excessive sensitivity to small speed changes D.remain in the neutral position
单项选择题 Fusible plugs are installed in fire-tube boilers to （）.
单项选择题 In comparison to exhaust valves, intake valves of diesel engines may be fabricated from low alloy steels because （）.
单项选择题 What preventative maintenance should be done frequently to diesel engine starting air receivers?（）
