【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
【判断题】当在机场附近(约 8—16 千米范围内)观测到 TS、DS、SS、FG、FC、SH、PO、BLDU、BLSA、BLSN、HZ 和 VA 时,应当在天气现象前不留空格冠以“VC”记录。
【判断题】哈特曼使用“结构的中性化”概念来实现自我离开本我,赋予自我自主性。所谓能量中性化是把本能的能量改变成非本能模式的过程。()
【判断题】《建设工程质量管理条例》规定,建设单位必须向有关的勘察、设计、施工、工程监理等单位提供与建设工程有关的原始资料,并且必须真实、准确、齐全。( )
【判断题】避强定位策略能使证券公司较快地在市场上站稳脚跟,并能在证券客户心目中树立形象,风险小。
【单选题】《建设工程质量管理条例》规定,施工单位必须建立、健全( )制度,严格工序管理,做好隐蔽工程的质量检查和记录。
【单选题】患者,女, 12岁,查体:胸骨左缘第三-四肋间闻及收缩期杂音,很响,伴明显震颤,但听诊器离开胸壁则听不到杂音。 该患者出现杂音的原因是( )