单项选择题

The highly efficient modem communication system began ______.

A．over a century ago
B．in the middle 1960s
C．in the late 1980s
D．in the year 1980
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单项选择题
Which of the following best expresses the main idea of the passage
A．It is optical fibers and lasers that have made the information superhighway possible.
B．People can communicate with each other more quickly now on the Internet.
C．It has taken quite a long time for the Internet to come into existence.
D．If one is seriously ill, he can always get help via the modem communication system.
单项选择题
The information superhighway came into existence because of ______.
A．copper wire cables
B．satellite communication
C．optical fibers
D．laser and optical fibers
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