单项选择题
A.the clearance of the main bearing B.the diameter of main bearing C.the gap of main beating D.the tolerance of main bearing
Additives （） protective layers on metal surfaces guardi...
单项选择题Additives （） protective layers on metal surfaces guarding them against corrosion.
A.damage B.form C.dissolve D.contaminate
Acid solution（） in the system can be tested from time t...
单项选择题Acid solution（） in the system can be tested from time to time by putting some on to a piece of lime.
A.strength B.dense C.percentage D.velocity
According to the way the energy of the exhaust gases is...
单项选择题According to the way the energy of the exhaust gases is utilized, pressure-charging can be divided into two main systems, namely, the constant-pressure system and （）.
A.the pulse-phase system B.the pulse Doppler system C.the pulse system D.the pulse interval
