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问题 选择题

一带电粒子在电场中从M点运动到N点的轨迹如图中虚线所示．若带电粒子在运动中只受电场力的作用，则下列判断正确的是（　　）

A．M点的电势比N点的电势低

B．该粒子带正电

C．粒子在M点的加速度比在N点的加速度小

D．粒子在M点的速度比在N点的速度小

答案

A、沿电场线方向电势逐渐降低，由图象可知M点的电势比N点的电势高．故A错误．

B、电场力指向曲线的凹侧，即电场力沿电场线向下，与场强方向相反，故该带电粒子带负电，故B错误．

C、电场线密处场强大，N处比M处密，故N点的场强比M点大，根据F=qE=ma知粒子在M点的加速度比在N点的加速度小，C正确；

D、从M到N的过程中电场力做负功，电势能增加，动能减小，故粒子在M点的速度比在N点的速度大，故D错误．

故选：C．

单项选择题

其行为是（）。

A.一般事件

B.一般事故

C.中等事故

D.严重事故

E.重大事故
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填空题

A good translator is by definition bilingual. The opposite is not ______(1) true, however. A born and bred bilingual will still need two__________(2) to become a translator: first, the skills and experience necessary for__________(3); second, knowledge of the field in which he or she will__________(4). The skills and experience for translation include the ability to write ______(5) in the target language, the ability to read and understand the_________(6) language material thoroughly, and the ability to work with the latest__________(7) and communication hardware and software.Does a born and bred bilingual__________(8) a better translator than someone who learned language B later in__________(9) There is no definite answer, but the following issues are important.__________(10), a born and bred bilingual often suffers from not truly knowing __________(11) language well enough to translate, with some even suffering from what __________(12) known as a lingualism, a state in which a person lacks_________(13) full, fluent command of any language. Second, born and bred bilinguals__________(14) don’’t know the culture of the target language well enough to_________(15) top-quality translations, or cannot recognize what aspects of the source language__________(16) its culture need to be treated with particular care, as they_________(17) in a sense too close to the language. And last, they often_________(18) the analytical linguistic skills to work through a sticky text.On_________(19) other hand, the acquired bilingual may not have the same in-depth _________(20) of colloquialisms, slang, and dialect that the born bilingual has. Also, the acquired bilingual will not be able to translate as readily in both directions (from B to language A and A to language B). Finally, born bilinguals often have a greater appreciation of the subtleties and nuances of both their languages than someone who learns their B language later in life can ever hope to have.
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