1. [单选题]中老年男性因前列腺肥大而引起______。
A. 排尿困难、尿线变细
B. 排尿淋漓不尽
C. 急性尿潴留
D. 以上都是
2. [单选题]The upper piston rings m large, slow-speed, two-stroke/cycle diesel engines are most effectively lubricated by oil ____.
A. fed from mechanical lubricators
B. thrown off from the main bearings
C. supplied from wick fed drip lubricators
D. flow from a centrifugal or banjo oiler
3. [单选题]除重伤员外应由全体人员轮流担任，值班一更的时间为：
A. 一小时(one hour)
B. 二小时
C. 三小时
D. 四小时
