在计算机局域网协议集中,数据链路层又可分为介质访问控制子层和 (52) :LAN参考

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问题:

在计算机局域网协议集中,数据链路层又可分为介质访问控制子层和 (52) :LAN参考模型中服务访问点SAP的作用是 (53) ;局域网中数据传输的误码率较低,一般约在 (54) ;在LAN的介质访问方式中,争用属于 (55) ;以太网的介质访问控制方式与CSMA相比较,其所做的改进是 (56)

A.10-3~10-2
B.10-6~10-4
C.10-7~10-6
D.10-11~10-8

考点:计算机软件水平考试初级网络管理员初级网络管理员上午试题
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What is distance learning It means that you study on your own, at home or wherever suits you. Recently, the world famous Open University in the United Kingdom has designed a new style of distance learning, which is called (1) . The phrase "Open Learning" means you study (2) . You read course material, work on course activities, and write (3) . The word "Supported" means you have help (4) , the student services staff at regional centres, and centralized areas such as (5) . You can also contact other students through tutorials and (6) , the University’s online conferencing system, and events and clubs organized by (7) . Most distance learning courses use printed paper materials. They also include some (8) materials such as a CD, DVD or video. Many courses have a web site and an (9) . You’ll need access to a computer (10) to make use of these. The Open University can help its students buy a computer and (11) the cost of accessing the Internet.

With most distance learning courses, no (12) are required to study. of course, you have to be aged 18 when your course starts but there is no (13) . Currently the Open University has around (14) undergraduate and more than 30,000 postgraduate students, of which 10,000 have (15) . Nearly all students are studying (16) . About 70 per cent of undergraduate students are in (17) . More than 50,000 students (18) by their employers for their studies. Most distance learning courses (19) . Some of them are even available in other parts of the world. With over 25,000 of its students living outside the UK, the Open University is the (20) that offers distance learning throughout the world.

18()

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根据我国现行宪法和法律的规定,我国的兵役制度是( )

A.志愿兵役制
B.义务兵役制
C.义务兵役制与志愿兵役制相结合,以义务兵役制为主
D.义务兵役制与志愿兵役制相结合,以志愿兵役制为主

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气与内劲是什么关系?

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大肠杆菌DNA聚合酶的催化反应需要的金属离子是:

A.Mg2+
B.Zn2+
C.Fe2+
D.Ca2+

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马丁一戴克指重装臵量程为()kN。

A、20~60

B、22~66

C、22.2~66

D、22.5~67

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