单项选择题
A.exhaust and suction process
B.suction and compression process
C.combustion and exhaust process
D.working and exhaust process
单项选择题 In the two stroke diesel engine, it is designed so that the oil impingement is timed to proceed only on the piston ring belt during（）
单项选择题 One advantage of a flash distilling plant when compared to a submerged tube distiller is（）
单项选择题 Sludge may be formed in the oil in the crankcase of a reciprocating air conditioning compressor as a result of （）