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

Before pumping up the crankcase oil,（） should be worked by hand to minimize corrosive action on the liners.

A.the indicators
B.the starting valves
C.the cylinder lubricators
D.the turning gear

你可能感興趣的試題

單項選擇題

Before being used the fuel service tank should be drained of （）.

A.soda solution
B.mechanical impurities
C.ballast
D.water and residuals

單項選擇題

Before a marine diesel engine is started the cylinders and pistons must be （）.

A.cooled to appropriate temperature
B.warmed up gradually to appropriate temperature
C.opened up and renewed
D.ground and polished

<nobr id="npe9h"></nobr>

<strong id="npe9h"></strong>