C Read this summary of the text and fill in the gaps using the list of words below.

distinction fibre-optic protocols synchronous

distributed systems LANs queries workstations

environments parses screen handling

Computer networks link computers locally or by external communication lines and software 1_______, allowing data to be exchanged rapidly and reliably. The 2_______ between local area and wide area networks is, however, becoming unclear. Networks are being used to perform increasingly diverse tasks, such as carrying e-mail, providing access to public databases, and for 3_______. Networks also allow users in one locality to share resources.

Distributed systems use networked computers. PCs or 4_______ provide the user 5_______. Mainframes process 6_______and return the results to the users. A user at his PC might make a query against a central database. The PC passes the query, written in a special language, to the mainframe, which then 7_______ the query, returning to the user only the data requested. This allows both the network and the individual PC to operate efficiently.

In the 1980s, at least 100,000 8_______ were set up world-wide. As 9_______ orbit satellites have lowered the price of long-distance telephone calls, data can be transmitted more cheaply. In addition, 10_______ cable has been installed on a large scale, enabling vast amounts of data to be transmitted at a very high speed using light signal. This will considerably reduce the price of network access, making global networks more and more a part of our professional and personal lives. Networks should also improve our work 11_______ and technical abilities.

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