Unit 1
Unit 2
Unit 3
Unit 4
Unit 5
Unit 6
Unit 7
Unit 8
內容試閱：
Task 2 Read the following passage and choose the best answer
from the four
choices marked A， B， C and D.
LAN is a group of computers and associated devices that share a
common communications line or wireless link. Typically， these
connected devices share the resources of a single processor or
server within a small geographic area （for example， within an
office building）.Usually， the server has applications and data
storage that are shared in common by multiple computer users.A LAN
may serve as few as two or three users （for example，several family
members） or as many as thousands of users （for example，in a large
company）.Today，the major LAN technologies include Ethernet，Token
Ring， FDDI and ARCNET.
Ethernet is by far the most commonly used LAN technology.
However，a number of corporations use the Token Ring technology.
FDDI is sometimes used as a backbone LAN interconnecting Ethernet
or Token Ring LANs. ARCNET，once the most commonly installed LAN
technology， is still used in the industrial automation
industry.
Typically，a suite of application programs can be kept on the LAN
server. If users need an application frequently，they can download
it from the server and then run it from their local hard disk.Users
can also order printing and other services as needed through
applications run on the LAN server. Files can be shared with others
via LAN with read and write access maintained by a LAN
administrator. LAN servers may be used as a web server as well if
safeguards are taken to secure internal applications and data from
outside access.
In some situations， a wireless LAN is preferable to a wired LAN
because it is cheaper and easier to install and maintain.
11.A group of computers and associated devices that share a
common communications line or
wireless link is called ____
A. Ethernet
B. Token Ring
C. LAN
D. WAN
12.Which is the most commonly-used LAN technology according to
the passage？
A. Ethernet.
B. Token Ring.
C. FDDI.
D. ARCNET.
13.Which LAN technology is still in use in the industrial
automation industry？
A. Ethernet.
B. Token Ring.
C. FDDI.
D. ARCNET.14. Where can the LAN users download an application
program when they need it？
A. From the LAN server.
B. From other users.
C. From the hard disk.
D. From a LAN administrator.
15.What services can the LAN server provide？
A. Downloading application programs.
B. Ordering printing.
C. Sharing files.
D. All of the above.
Task 3 Read the following passage and complete the sentences
below with the information given in the passage.
Wireless connections can extend or replace a wired infrastructure
in situations where it iscostly， inconvenient， or impossible to lay
cables.
To connect the network in two buildings， you can either use a
link provided by atelecommunications vendor or create a
point-to-point wireless link using wireless LANtechnology. The
former charges a fixed installation cost and ongoing recurring
costs while thelatter eliminates recurring costs， which provide
significant cost savings to organizations.
Wireless technology is perfect for meeting temporary needs.For
example， at a conventionor a trade fair， the network is needed for
only a specific amount of time.In this situation，setting up
wireless LAN is a much better choice than deploying the physical
cables requiredfor the traditional network.
Some types of buildings，such as historical buildings，might be
governed by buildingcodes that prohibit the use ofwiring. Setting
up wireless networks is an important alternative.
The wiring-free aspect of wireless LAN is also very attractive to
homeowners who wantto connect the various computers in their home
without having to drill holes and pull networkcables through walls
and ceilings.
Wireless network is also a perfect technology for environments
where movement isrequired.For example，in a large company， employees
take their laptops to a conference room，or in retail shops，the
sales people need walk around to talk with visiting customers and
enterinventory information directly into the database.In this
case，wireless network that covers thewhole area is much more
convenient.
……
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