单项选择题
A.decrease in ignition lag
B.increase in fuel economy
C.reduction in lube oil viscosity
D.increase in cylinder misfiring
单项选择题 The plunger in a jerk pump is rotated until the release port is uncoveredIf the port remains uncovered all of the time, which of the listed operations will occur?（）
单项选择题 If the compensating needle valve of a hydraulic governor is opened more than necessary the governor will （）
单项选择题 The double bottom in a vessel is a space comprised of （）