单项选择题
A.thermal B.mechanical C.plastic D.elastic
Around the combustion chamber, all the main components ...
单项选择题Around the combustion chamber, all the main components are to give low thermal strains and the smallest, circumferentially symmetric deformations for good sealing between piston rings and liner（）
A.drill cooled B.hole cooled C.tube cooled D.bore cooled
Top piston rings are plasma coatedIt gives added safety...
单项选择题Top piston rings are plasma coatedIt gives added safety for the of new lines（）
A.running-in B.running-out C.running on D.running down
For auxiliary engines the permissible overload is （） fo...
单项选择题For auxiliary engines the permissible overload is （） for one hour every twelve hours.
A.10% B.15% C.20% D.25%
