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问题 选择题

如图所示，一小虫在半径为R的半球形碗内沿碗面缓慢向上爬．假定小虫与碗之间动摩擦因数是μ，小虫与球心的连线和竖直方向夹角为α，设最大静摩擦力与滑动摩擦力相等，则下列说法正确的是（　　）

A．小虫可以沿碗爬到碗的顶端

B．小虫沿碗爬到的位置和动摩擦因数有关，最高点满足tanα=μ

C．小虫沿碗爬到的位置和动摩擦因数有关，最高点满足sinα=μ

D．条件不足，无法判断小虫能爬到的具体位置

答案

小虫缓慢上爬，可以认为小虫处于平衡状态，则合力始终为零，

小虫爬到最高位置时，达到最大静摩擦力，根据共点力平衡有：mgsinα=μmgcosα，解得：tanα=μ．

故B正确，A、C、D错误．

故选：B．

填空题

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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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