1. [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
2. [单选题]硅胶管消毒灭菌不能用：
A. 煮沸
B. 0.1%新洁尔灭浸泡
C. 环氧乙烷熏蒸
D. 70%酒精浸泡
