润滑可以减少磨损，延长设备使用寿命。

以赤道为界，南纬和北纬的度数分别向南、北排列，其大小变化规律是 [ ]

A．越来越大

B．大小不变

C．大小相间分布

D．越来越小

李某，男，36岁，胸腔手术后胸膜腔闭式引流管不慎自胸壁伤口脱出，首要的措施是

A．急呼医生处理

B．将引流管重新插入胸腔

C．手指捏紧引流口皮肤，勿使进气

D．换药室使凡士林纱布阻塞引流口

E．急送手术室

以下关于酒渣鼻的描述正确的有()

A．本病多累及中年人，女性居多

B．可并发痤疮及脂溢性皮炎

C．鼻赘往往发生于男性患者

D．病情长期发展可成为鼻赘期

One of the difficulties in building an SQL-like query lange for the Web is the absence of a database schema for this huge, heterogeneous repository of information. However, if we are interested in HTML documents only, we can construct a virtual (66) from the implicit structure of these files. Thus, at the highest level of (67) , every such document is identified by its Uniform Resource Locator (URL), has a title and a text Also, Web servers provide some additional information such as the type, length, and the last modification date of a document. So, for data mining purposes, we can consider the site of all HTML documents as arelation:
Document (url, (68) , text, type, length, modify)
Where all the (69) are character strings. In this framework, anindividual document is identified with a (70) in this relation. Of course, if some optional information is missing from the HTML document, the associate fields will de left blank, but this is not uncommon in any database.

A．presentation

B．control

C．abstraction

D．protocol

发动机控制面板在什么位置（）

A.头顶板；

B.头顶板和中央操纵台；

C.中央操纵台。