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问题 问答题

以下说法正确的是（　　）

A．磁感线是磁场中实际存在的曲线

B．地磁场的南极在地理的北极附近

C．通电导体在磁场中受力方向与磁场方向无关

D．在电磁感应现象中，电能转化为机械能

答案

A、磁体周围存在着磁场，磁感线是为了形象的来描述磁感线而引入的一种物理模型，不是真实存在的，故A错误．

B、在磁体外部，磁感线是从N极发出，回到S极；小磁针静止时，N极指示地理的北极，故据此即可判定地理位置的南北极与地磁的南北极正好是相反的，故B正确．

C、通电导体在磁场中受力的作用，而且受力的方向与磁感线方向与电流方向有关；故C错误．

D、根据电磁感应现象制成了发电机，而发电机是把机械能转化为电能，故D错误．

故选B．

选择题

“十二五”规划纲要提出，扩大增值税征收范围，相应调减营业税等税收。合理调整消费税征收范围、税率结构和征税环节。财政部文件明确表示，在一些生产性服务业领域推行增值税改革试点。从经济生活角度看，扩大增值税征收范围的依据是（ ）

①它只对所得额征税，可以避免对一个经营额重复征税

②它可以防止前一生产经营环节企业的偷漏税行为

③它有利于促进生产的专业化和体现公平竞争

④它是财政收的最重要来源

A．①②

B．②③

C．①④

D．③④
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单项选择题

There is a difference between science and technology. Science is a method of answering (1) questions; technology is a method of solving practical problems. Science has to do with discovering the facts and relationships between (2) phenomena in nature and with establishing theories that (3) to organize these facts and relationships; technology has to do with tools, techniques, and (3) for applying the findings of science. Another (5) between science and technology has to do with the progress in each.

Progress in science (6) the human factor. Scientists, who seek to understand the universe and know the truth within the highest degree of (7) and certainty, cannot (8) their own or other people’s likes or dislikes or to popular ideas about the fitness of things. What scientists discover may shock or (9) people-as did Darwin’s theory of evolution. But even an unpleasant truth is (10) than likely to be useful; besides, we have the choice of refusing to believe it! But (11) so with technology; we do not have the choice of refusing to hear the sound produced by a supersonic aircraft flying overhead; we cannot refuse to breathe polluted air. (12) science, progress in technology must be measured (13) the human factor. The purpose of technology is to serve people—people (14) , not merely some people; and future generations, not merely those who presently wish to (15) advantage for themselves.

We are all familiar with the (16) use of technology. Many people blame technology itself (17) widespread pollution, resource depletion (枯竭) and even social decay in general—so much (18) the promise of technology is " (19) " That promise is a cleaner and healthier world. If wise applications of science and technology do not (20) a better world, what else will

3（）

A.serve

B.assume

C.intend

D.prove
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