问题：
[单选] The ports are drilled in the liners at an angle of approx 20℃ the result being that （） is given a rotary movement.
the scavenging air。the exhaust gases。the mixed air。the spray oil。
问题：
[单选] The position of the interface between oil and water within the centrifuge is achieved by the use of （）.
gravity disc。centrifugal bowl。a stack of discs。main sealing ring。
问题：
[单选] The position of the piston parts in relation to each other is secured by means of （） in the crown.
a mark。a bolt。a dowel pin。a measuring tool。
问题：
[单选] The position of the piston parts in relation to each other is secured by means of （） and a dowel pin in the crown.
bosses。through bolts。machine-turned recesses。long stud。
问题：
[单选] The power generated in the turbine must （） that required by the compressor.
be less than。be larger than。be as large as。not be so large a。
问题：
[单选] The pressure of pilot air is usually （） than that of starting air.
higher。lower。low。high。
问题：
[单选] The pressurized air is usually cooled to increase the charge air （）.
viscosity。density。velocity。electricity。
问题：
[单选] The primary duty of lube oil is to reduce （） between the working parts of an engine.
power output。friction and wear。indicated pressure。rated horsepower。
问题：
[单选] The process of loop scavenge is that the exhaust will be via ports （） the air ports and controlled by the same piston.
behind。far from。adjacent to。in front of。
问题：
[单选] The process to remove exhaust gases by blowing in fresh air is called （）.
charging。supercharging。starting。scavenging。
