北京邮电大学14秋《通信英语》在线作业2

14秋《通信英语》在线作业2
试卷总分：100 奥鹏学习网（aopeng123.cn) 发布
单选题
一、单选题（共 20 道试题，共 100 分。）
V
1. The simplest way _______ a file on another host is to copy it across the network to your local host.
A. access
B. accessing
C. be accessed
D. to access
此题选: D 满分：5 分
2. Designers have found it convenient to organize these nodes into a hierarchy or tree topology,______ five classes of switching centers or nodes.
A. to consist of
B. to consisted of
C. consist of
D. consisting of
此题选: D 满分：5 分
3. Multimedia is no longer a toy or a game technology. It is moving into our lives in many ways. It is _______ our banking, shopping,education travel and work pattern.
A. affecting
B. affect
C. affected
D. to affect
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4. Each subscriber connects via a local loop to a switching center,________ an end office.
A. known as
B. know as
C. to know as
D. knowing as
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5. The Internet is a giant ______ of computers located all over the world that communicate with each other.
A. mesh
B. body
C. network
D. framework
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6. The most obvious disadvantage of asynchronous data transmission is the need for a start, parity and stop bit for each transmitted _____ .
A. words
B. characters
C. character
D. link
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7. There is an inherent advantage for _______ noisy environment by choosing digital transmission.
A. converting
B. sampling
C. overcoming
D. specifying
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8. Today, certain models of pagers are even equipped with display capability of providing optical messages consisting of l0 to 8O _____ , and thus substantially increasing the efficiency of the system.
A. characters
B. character
C. global
D. case
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9. An asynchronous serial data link is said to be character oriented, as information is transmitted in the form of groups of bits called _____ .
A. word
B. case
C. character
D. format
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10. The remaining centers simply serve the function of ________ traffic so as to reduce transmission facility requirements.
A. to concentrate
B. concentrate
C. concentrating
D. concentrated
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11. The high-usage trunks are______ as dashed lines, and the backbone hierarchical network shown as solid lines.
A. to say
B. to depict
C. depicted
D. depicting
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12. Serial data transmission systems are found in the telephone, Morse code, and even the smoke signals once _______ by native Americans.
A. using
B. to be used
C. use
D. used
此题选: D 满分：5 分
13. Initially, when no information is being transmitted, the line is in an idle _____ .
A. time
B. type
C. state
D. groups
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14. The problem is easily overcome by specifying a _______ format, where at the start of each frame a unique sequence of pulses is placed so as to identify the start of the frame.
A. data
B. block
C. picture
D. frame
此题选: D 满分：5 分
15. At the receiving terminal a ________ is arranged to separate the 8-digit sequences into the appropriate channels.
A. multiplexer
B. end
C. ending
D. demultiplexer
此题选: D 满分：5 分
16. There are over 19000 end offices in the United States, so it is clearly _________ for each end office to have a direct link to each other end office; this would require on the order of 2×108 links.
A. practical
B. impractical
C. to practice
D. to impractical
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17. First we examine how the _____ stream is divided into individual bits and the bits grouped into characters in asynchronous serial data link.
A. system
B. data
C. type
D. character
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18. The word “multimedia” is being used _______ a mixture of hardware, software and applications, with a consequent confusing in people’s minds as to what it is.
A. to descbibe
B. to be describe
C. describe
D. describing
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19. The CD-ROM is used _______ data that represents visual imagery and current units can store up 650 Mbytes of data.
A. to describe
B. to identify
C. to specifying
D. to store
此题选: D 满分：5 分
20. The transmitter then sends the character, 1 bit at a time, by _______ each successive bit on the line for a duration of T seconds, until all bits have been transmitted.
A. being placed
B. placing
C. place
D. placed
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