填空题
Internet, computer-based global information system. The
Internet is composed of many interconnected computer networks. Each network may
link tens, hundreds, or even thousands of computers, enabling them to share
information with one another and to share computational resources such as
powerful supercomputers and databases of information. The Internet has made it
possible for people all over the world to communicate with one another
effectively and inexpensively.
41__________.
The
Internet has brought new opportunities to government, business,
and education. Governments use the Internet for internal communication,
distribution of information, and automated tax processing. In addition to
offering goods and services online to customers, businesses use the Internet to
interact with other businesses.
42__________.
Use of the Internet has grown tremendously since its inception. The Internet's
success arises from its flexibility. Instead of restricting component networks
to a particular manufacturer or particular type, Internet technology allows
interconnection of any kind of computer network.
43__________.
Internet service providers (ISPs) provide
Internet access to customers, usually for a monthly fee. A customer who
subscribes to an ISP's service uses the ISP's network to access the Internet.
Because ISPs offer their services to the general public, the networks they
operate are known as public access networks.
44__________.
An organization that has many computers
usually owns and operates a private network, called an
intranet, which connects all the computers
within the organization: To provide Internet service, the
organization connects its intranet to the Internet. Unlike public access
networks, intranets are restricted to provide security.
45__________.
A. The current number of people who use the
Internet can only be estimated. One survey found that there were 61 million
Internet users worldwide at the end of 1996, 148 million at the end of 1998, and
407 million by the end of 2000. ,Some analysts said that the number of users was
expected to double again by the end of 2002.
B. Only authorized
computers at the organization can connect to the intranet, and the organization
restricts communication between the intranet and the global Internet. The
restrictions allow computers inside the organization to exchange information but
keep the information confidential and protected from outsiders.
C. Unlike traditional broadcasting media, such as radio and television,
the Internet does not have a centralized distribution system. Instead, an
individual who has Internet access can communicate directly with anyone else on
the Internet, make information available to others, find information provided by
others, or sell products with a minimum overhead cost.
D. No
network is too large or too small, too fast or too slow to be interconnected.
Thus, the Internet includes inexpensive networks that can only connect a few
computers within a single room as well as expensive networks that can span a
continent and connect thousands of computers.
E. Many
individuals use the Internet for communicating through electronic mail (e-mail),
for news and research information, shopping, paying bills, and online banking.
Educational institutions use the Internet for research and to deliver courses
and course material to students.
F. In the United States, as in
many countries, ISPs are private companies; in countries where telephone service
is a government-regulated monopoly, the government often controls
ISPs.
G. The Internet has doubled in size every 9 to 14 months
since it began in the late 1970s. In 1981 only 213 computers were connected to
the Internet. By 2000 the number had grown to more than 100 million.