99色精品-9色在线-99色在线-99色视频 国产欧美日产一区二区三区_亚洲精品亚洲人成在线观看_四虎在线精品永久观看_免费一级a一片久久精

單項選擇題

Trunk-type diesel engine pistons are most effectively cooled by heat()

A.conducted through the engine block
B.conducted to water cooled cylinder walls
C.conducted through the piston crown
D.loss to escaping exhaust gases

微信掃碼免費搜題