（） device is provided to prevent starting air from being admitted to the cylinder before the reversing is completed.

（） are generally formed in the frame of the both in-lin...

单项选择题（） are generally formed in the frame of the both in-line and Vee engines to give maintenance access to the crankshaft main and connecting rod large end bearing.

（） are commonly used in mechanical-hydraulic governor（调...

单项选择题（） are commonly used in mechanical-hydraulic governor（调速器） to sense engine speeds.

A （）is the foundation of the engine, without the suppor...

单项选择题A （）is the foundation of the engine, without the support of which the shaft alignment in particular, and engine structure as a whole, would inevitably be lost.