单选题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（）Adrill cooledBhole cooledCtube cooledDbore cooled
单选题
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
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