单项选择题
A.to stiffen B.to soften C.to loosen D.to wear
“Stand by engine” means （）.A.prepare to stop the engine...
单项选择题“Stand by engine” means （）.
A.prepare to stop the engine B.assemble an engine on its bedplate C.make an engine ready for starting D.make an engine run steadily
Smaller engines can be made more rigid than large ones ...
单项选择题Smaller engines can be made more rigid than large ones and may not have （）.
A.through bolts B.turbo-chargers C.bed plates D.columns
A.through bolts B.dividing walls C.sloping surfaces D.relative angles
