A.The reward the prisoners get for their work. B.The comfortable accommodation. C.The way the prisoners are treated. D.The officers' sympathy for the prisoners.
拍照语音搜题,微信中搜索"皮皮学"使用
参考答案:
参考解析:
知识点:
皮皮学刷刷变学霸
举一反三
【单选题】Proper lubrication of the main bearings is more easily obtained in a single acting, four-stroke/cycle diesel engine than in a tow-stroke/cycle diesel engine because________.
A.
The direction of pressure on the journal in four-stroke engine is continuously
B.
positive feed lubricators are installed on all bearings of four-stroke engine, whereas as a splash feed system is used on tow-stroke engine
C.
four-stroke engines usually utilize a heavier grade of oil than tow-stroke engines
D.
Low-stroke engines usually consume less lube oil than four-stroke engines