单项选择题
The process to remove exhaust gases by blowing in fresh air is called （）.
A.charging B.supercharging C.starting D.scavenging
单项选择题 The process of loop scavenge is that the exhaust will be via ports （） the air ports and controlled by the same piston.
单项选择题 The primary duty of lube oil is to reduce （） between the working parts of an engine.
单项选择题 The pressurized air is usually cooled to increase the charge air （）.
