在如图所示电路中,当闭合开关后,滑动变阻器的滑动片P向右移动时 A.电压表示数

题型:选择题

问题:

在如图所示电路中,当闭合开关后,滑动变阻器的滑动片P向右移动时

 

A.电压表示数不变,灯变暗

B.电流表示数变大,灯变暗

C.电压表示数不变,灯变亮

D.电流表示数变小,灯变亮

考点:欧姆定律及其应用
题型:选择题

在不考虑品牌的前提下,选择运输商以()为主要依据。

A.运价

B.运输网络

C.最短运输时间

D.运价与运输时间的均衡

题型:选择题

下列完全是质量单位的一组是[ ]

A.克、吨    

B.千克、千米  

C.米、吨

题型:选择题

程序设计语言的基本成分是数据成分、运算成分、控制成分和 ( )

A.对象成分
B.变量成分
C.语句成分
D.传输成分

题型:选择题

One of the difficulties in building an SQL-like query language for the Web is the absence of a database (131) for this huge, heterogeneous repository of information. However, if we are interested in HTML documents only, we can construct a virtual schema from the implicit structure of these files. Thus, at the highest level of (132) , every such document is identified by its Uniform Resource Locator (URL), and a (133) and a text. Also, Web severs 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 set of all HTML documents as a relation:
Document (url, rifle, text, type, length, modif)
Where all the (134) are character strings. In this framework, an individual document is identified with a (135) in this relation. Of course, if some optional information is missing from the HTML document, the associate fields will be left blank, but this is not uncommon in any database.

A.protocol

B.control

C.abstraction

D.presentation

题型:选择题

简述工业社会的经济结构与教育职能的特点。

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