单项选择题
In diesel engines designed with a crosshead, the motion of the piston rod can be described as （）.
A.reciprocating at the piston pin, rotary at the crank pin B.reciprocating at the crank pin, rotary at the piston pin C.straight reciprocation D.straight rotation
单项选择题 Immediately after any diesel engine is started, the engineer should check the （）
单项选择题 The rate of heat transfer in a water-tube auxiliary boiler can be increased by （）.
单项选择题 The term “proper metering”, as applied to a diesel fuel injection system, can be best defined as （）.
