问题 填空题

Although no longer slavers after the Civil War, American blacks took no significant part in the life of white America except as servants or laborers. Many thousands of them emigrated from the war-ravaged South to the North from 1865 to 1915 in the hope of finding work in the big industrial cities. Whole communities of blacks crowded together into ghettos in New York City, Chicago and Detroit, where once the poor white immigrants had lived. These ghettos, neglected by the city authorities, became slums. The schools to which black children went were hopelessly inadequate. Unemployment in black ghettos remained consistently higher than in white communities.

41. Serious problems with black ghettos.__________

Stable family life was difficult to maintain.

42. The extreme poverty of the blacks. __________

In the late 1970s, nearly a third of all blacks still belonged to the so-called "underclass", they are so "under-privileged" and poor that they cannot seize the opportunity for advancement.

43. Efforts to put an end to racial discrimination. __________

Race relations in the USA continue to be a thorny problem.

44. Improvements in lives of the blacks. __________

Despite some setbacks, race relations are improving.

45. Prevailing violence in solving racial problems. __________

It is said that television had an enormous influence on frustrated and bitter blacks, for it showed them bow much better whites on the whole lived than blacks. At the end of the 1960s, there were serious riots in many cities.

The violence quickly died down. Blacks began to use their votes to exert political pressure. Cities like Atlanta (Georgia), Gary (Indiana), and Los Angeles (California) elected black mayors. Integration of schools, despite resistance from white groups, goes on, and the proportion of blacks in American colleges has increased dramatically in the last 20 years. There are reasons to maintain a cautious optimism that progress in race relations will continue.

[A] It has been estimated that there are more than 20 million Americans in this category, 10% of the population, including many millions of whites.

[B] Blacks are gaining in self-confidence. In more and more areas they are winning control of their communities, and their standard of living is going up faster than that of the poor whites. It is still a hard struggle. There is still prejudice and even some hatred, but in most walks of American life there are now more blacks than ever before.

[C] The era of blatant discrimination ended in the 1960s through the courageous actions of thousands of blacks participating in peaceful marches and sitins, to force Southern states to implement the Federal desegregation laws in schools and public accommodations. Down came the "whites only" notices in bused, hotels, trains, restaurants, sporting events, restrooms and on park benches that once could be found everywhere throughout the South. Gone were the restrictions that prevented blacks voting. Gone, too, were the hideous lynch-ings, which since the Civil War had caused the death of thousands of innocent blacks— hanged without trial by white mobs. However, even today, poor, uneducated lacks do not always receive the same degree of justice that the more affluent and better educated can expect.

[D] Many blacks chose to keep silent about their unfairness instead of resorting to violence. But their silence was also problem provoking: on the one hand, silence would build up a lot of complaints and hatred in their minds, thus resulting in a negative approach to life and everything; on the other hand, silence would give the whites an impression that the blacks take the reality for granted and put more racial discrimination on them.

[E] Unemployed fathers would on occasion walk out of their homes and never return. Children neglected by their parents turned in some instances to drugs and crimes. There are more than 700 murders a year in cities like New York, Detroit, Los Angeles and Houston, and most of these deaths are of blacks killed by blacks. The black ghettos are dangerous both for blacks and non-blacks.

[F] Radical blacks like the Black Panthers demanded a free black state within the Union, and advocated violence to achieve that end and to protect themselves against what they felt was police brutality toward blacks. For a while, violence overshadowed the influence of the greatly respected pacifist black, Martin Luther King, Jr. , who had provided the inspiration and leadership for those devoted to a peaceful change and whose murder in 1968 stunned America.

44()

答案

参考答案:B

解析:

[解题思路] 该段主题句是“黑人生活的改善”,[B]选项正好叙述了黑人生活的改善,虽然中间谈到仍有不足,但结尾句中的“but’’把重点引向了“各行各业中黑人的人数在上升”,还是说明了黑人生活的改善。

单项选择题
问答题


阅读以下关于嵌入式系统软件设计方面的叙述,回答问题1至问题3。
某公司承担了一项嵌入式系统软件开发项目。该项目主要用于车载电子系统中监视发动机及燃油系统等系统工作状况,并通过综合仪表显示给驾驶员。经过多次与用户沟通,形成以下技术要求:
(1)本项目的硬件平台由主处理机模块和多种接口模块组成,底板采用标准VME总线(硬件结构图如图3-1所示),具体硬件模块配置如下。


①主处理机模块(CPM)采用PowerPC755,主频266MHz,配有SDRAM存储器和FLASH存储器;提供一个定时/计数器;支持16级中断和二级cache。
②输入输出模块(IOC)支持16路RS422接口信号,传输速率不低于115.2kbps,IOC模块与CPM模块的数据交换采用64KByte双端口存储器。
③离散量接口模块(DAM)支持64路开关型离散量输入输出接口;2路频率量输入;12位A/D转换器和12位:D/A转换器。
④图形处理模块(GPM)用于显示图形,支持OpenGL标准接口软件。
⑤MBI模块主要提供1553B外总线接口,PSM为电源支持模块。
(2)本项目软件主要工作在CPM模块中,完成对外部设备的数据采集、分析和相应的控制,将监视结果以图形方式显示给驾驶员。该系统的软件主要包括外部接口驱动软件、VME数据传输软件、处理软件、图形显示和外总线(1553B)数据交换软件。要求数据的采集必须确保每帧数据无丢失,并在本帧内完成数据的处理工作,本帧信息显示给驾驶员的时刻最晚不能超过下帧。详细的技术要求如下。
①16路RS422接口主要完成对汽车燃油系统、动力系统和驾驶员命令的数据采集与控制。RS422数据传输格式将以32Byte为基本数据块,分别以20ms、40ms、60ms和1s四个不同周期交换数据。
②64路离散量数据主要监控发动机工作状态,要求每10ms采集一次,并在下一个10ms周期内将发动机状况显示到驾驶员座舱。
③多路模拟量数据主要采集发动机转速、油量及汽车的其他数据,为驾驶员监控汽车状态提供必要的量化数据。模拟量数据的刷新频率为1s。
④外总线(1553B)主要完成该系统与汽车其他电子系统的数据交换。


公司将本项目交给项目主管李工实施,要求李工按技术要求完成本项目的软件设计工作,公司根据合同关于“数据的采集必须确保每帧数据无丢失,并在本帧内完成数据的处理工作,本帧信息显示给驾驶员的时刻最晚不能超过下帧”的要求,提醒李工设计中重点考虑整个系统的实时性问题。李工完成设计后,提交公司评审,会上就李工设计中存在的缺陷展开了激烈讨论,最终达成一致。

【问题3】
请用150字以内的文字说明针对IOC模块的多路RS422接口的数据采集,其驱动程序使用中断方式或查询方式的主要差别是什么主要优缺点有哪些