单项选择题 Pitting in the area close to the pitch line and on the same end of each gear tooth of a reduction gear unit would be caused by （）

单项选择题 When used with reversing reduction gears, medium-speed diesel engines should be bolted to their foundations with fitted bolts at the drive end and clearance(loosely fitted) bolts in other locations √This is done to （）

单项选择题 Some medium and high-speed diesel engines require reduction gear units to provide a useful propeller speedIn most reduction gears, the bull gear（）