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问题 单项选择题

声卡的性能指标主要包括（）和采样位数；在采样位数分别为8、16、24、32时，采样位数为（）表明精度更高，所录制的声音质量也更好。

在采样位数分别为8、16、24、32时，采样位数为（）表明精度更高，所录制的声音质量也更好。

A．8

B．16

C．24

D．32

答案

参考答案：D

解析：

试题(7)、(8)分析 本题考查计算机系统及设备性能方面的基础知识。 声卡的性能指标主要包括采样频率和采样位数。其中，采样频率即每秒采集声音样本的数量。标准的采样频率有三种：11．025kHz(语音)、22．05kHz(音乐)和44．1kHz(高保真)，有些高档声卡能提供5kHz—48kHz的连续采样频率。采样频率越高，记录声音的波形就越准确，保真度就越高，但采样产生的数据量也越大，要求的存储空间也越多。采样位数为是将声音从模拟信号转化为数字信号的二进制位数，即进行A/D、D/A转换的精度，位数越高，采样精度越高。

选择题

在法国的第一个共和制 * * 之下，行使立法权的机构是

A．国民议会

B．制宪议会

C．国民公会

D．立法议会
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问答题

Passage 1 Development of the City Whatever the particular circumstances of a city, though, its vigour was likely to be affected by technological change. Just as it was improvements in farming that brought about the surpluses that made possible the first fixed settlements, so it was improvements in transport that made possible the development of trade on which the prosperity of so many cities depended. Other technological changes made it possible to survive in a city. The Romans, for instance, constructed aqueducts to bring fresh water to their towns and sewers to provide sanitation. But only the rich benefited. Most Romans, and many city-dwellers throughout history, lived in squalor, and many died of it. Towns were crowded and insanitary; people were often malnourished; and disease spread fast. Though cities grew in size and number for long periods, they could decline and fall, too. Between 1000 and 1300 Europe’s urban population more than doubled, to about 70m (thanks partly to a new system of crop rotation, made possible by better tools). Then, with the Black Death, it fell by a quarter. Country people died too, but the city-dwellers were especially vulnerable. Their health depended above all on clean water and sanitation, which few had, and cheap soap and medicines, which had yet to be invented. Not surprisingly, the next big change in the development of the city also turned on a leap in technology: the invention of engines and manufacturing machinery. The Industrial Revolution did nothing at first to make urban life easier, but it did provide jobs—lots of them. With the new factories of the industrial age that began in the late 18th century was born an entirely new urban era. Peasants left the land in their multitudes to live in new cities, first in the north of England, then all over Europe and North America. By 1900, 13% of the world’s population had become urban.
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