| 软件水平考试系统分析师易错题（2019/2/19） |
| 第1题：如果对一个关系实施了一种关系运算后得到了一个新的关系，而且新的关系中的属性由该运算决定，这说明所实施的运算关系是( )
A、选择 B、投影 C、连接 D、笛卡儿积 |
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| 第2题：软件工程方法的产生源于软件危机，下列( )是产生软件危机的内在原因
I 软件复杂性 II 软件维护困难 III 软件成本太高 IV 软件质量难保证 A、I B、III C、I和IV D、III和IV |
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| 第3题：在谓词演算中，P(a)是xp(x)的有效结论，根据是( )。
A、US规则 B、UG规则 C、ES规则 D、EG规则 |
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| 第4题：在下列各项中,一个计算机网络的3个主要组成部分是( )
1、若干数据库2、一个通信子网 3、一系列通信协议4、若干主机 5、电话网6、大量终端 A、1、2、3 B、2、3、4 C、3、4、5 D、2、4、6 |
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| 第5、6、7、8、9题：In the following essay, each bland has four choices.Choose the best answer and write down on the answer sheet. With the implementation of (6) the so – called network has become a reality. The provision of such facilities is the most important part of the network requirements. However, in many applications the communicating computers may be of different types. This means that they may use different programming languages and, more importantly, different forms of (7) interface between user(application)program, normally referred to ,as application processes, and the underlying communication services may be (8). For example, one computer may be a small single-user computer, while another may be a large (9) system. In the earlier days of computer communication, these issues meant that only closed communities of computers (that is, from the same manufacturer) could communicate with each other in a meaningful way. IBM’s systems NetworkArchitecture (SNA、andDEC’sDigital NetworkArchitectureDNA、are just two examples of communication software packages produced by manufacturers to allow their systems to be intercormected together. These proprietary packages, however, of which there am still many inexistence, do not address the problem of universal interconnect ability, or open systems interconnection. In an attempt to alleviate this problem,(10) ,in the late 1970s,formulated a reference model to provide a common basis (or the coordination of standards developments and to allow existing and evolving standards activities to be placed into perspective with one another.
(6) A、communicationchannel B、protocols C、datachannel D、publiccommunication (7) A、database B、datarepresentation C、protocols D、datacommunication (8) A、same B、similar C、different D、dependent (9) A、multi-user B、client C、server D、full-user (10) A、DNA B、SNA C、theOSI D、theISO |
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