离心泵叶轮在充满液体的泵壳内旋转时()表面与液体发生相互摩擦,引起摩擦损失。
A、叶轮盖板
B、泵壳
C、轴承
D、叶轮
参考答案:A
与慢性胃炎和消化性溃疡有密切关系的病原菌为
A.鼠伤寒沙门菌
B.胎儿弯曲菌
C.空肠弯曲菌
D.副溶血性弧菌
E.幽门螺杆菌
Software engineering is the science and art of specifying, designing, implementing, and (66) with economy, timeliness and elegance, programs, (67) and operating procedures whereby computers can be made useful to humanity.
This definition implicitly sets (68) the basic goal of software engineering research and development: The basic goal of software engineering is to facilitate specification, design, implementation and evolution of programs, documentation and operating (69) which are useful to humanity in an economic, (70) and elegant manner (using the appropriate science and art).
(67)处填()。
A.documents
B.data
C.documentation
D.media