анарка3

26.08.2020 13:27 •  Английский язык

Find the sentences with :
A) a verb in :
the Present Continuous (1)
the Present Perfect (1)
the Past Perfect (1)
the Passive voice (2)
B) a modal verb ( 2)
С) an adjective in the comparative degree (2)

Текст:
Networking for a Sustainable Development
By itself, a computer is a valuable device. But there are limits to the amount of information and the variety of programs that can be assembled on even the largest individual machine. The usefulness of any computer increases dramatically when it is linked to other machines, since networks allow users to pool their resources. A small network–by wiring together all the computers in an office or school, for example can make it possible to share printers, databases of contacts or clients, or a fax system.
Large networks put enormous resources and reliable, inexpensive global communications at the fingertips of ordinary citizens. Those with small computers can gain access to the enormous processing power of larger machines. A climate scientist in New-York, for example, may develop programs on a small workstation in her own laboratory, and then run them on a supercomputer in California or North Carolina, with the results fed back to her machine.
The rapidly growing international web of computer systems has made it easy for many people to keep in touch with friends and colleagues on the other side of the world. E-mail is cheaper than international phone calls, faxes, or express package service, and allows its users to bypass busy signals, unpredictable postal service, and schedule conflicts created by different time zones.
Computer networks are still in their adolescence. While some systems have millions of users, they can still be difficult to use. And, like local phone systems at the dawn of the telephone age, many networks today are unable to communicate with each other, either because they are not physically connected, or because they are built to different standards. This situation is changing rapidly, however. The Internet is a fastgrowing collection of computer networks that can talk to one another. It is beginning to resemble the global phone system in its scope and common design.
The Internet originated in 1969 as a link between computer centers doing defense-related research across the United States. By the late 1980s, it had grown to become an important link for other academic researchers and reached outside academia and the borders of the United States.
The Internet can be difficult to use, and the amount and variety of information available through it can be bewildering. However, many host computers now offer special programs that allow users to search thousands of systems for information on particular topics without knowledge of special commands or network addresses. Internet users are able to discuss wild variety of topics via thousands of computer conferences.
Functioning like an electronic bulletin board – participants “post” contributions, which are then available for others to read when they log in – they make possible conversation that are lively, global and immediate. When something significant happens anywhere in the world, word of it usually spreads more quickly through computer networks than through other information channels, since there are millions of users and fewer delays than are usually involved in television, radio, or telephone communication.