单项选择题 The scavenge port inspection should be carried out（）, to obtain the most reliable result with regard to the effectiveness and sufficiency of the cylinder lubrication and the combustion cycle (complete or incomplete).

单项选择题 Always ensure that the turning gear is（）, even at the quay, the wake from other ships may turn the propeller and thus the engine.

单项选择题 In general, the oil mist defectors include a base plate with air blast pumpThe function of air blast pump is to （）crankcase.