What is the way that the computer viruses infect the computer systems?

A．They invade the computer and make it a place for manufacturing．

B．They spread throughout the whole system by quickly copying themselves．

C．They infect the hard disc and the whole system．

D．They spread viruses inside the computer system．

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答案解析

The computer virus is an outcome of the computer overgrowth in the 1980s. The cause of the term "computer virus" is the likeness between the biological virus and the evil program infected with computers. The origin of this term came from an American science fiction The Adolescence of P-1 written by Thomas J. Ryan, published in 1977. Human viruses invade a living cell and turn it into a factory for manufacturing viruses. However,computer viruses are small programs. They expand by attaching a copy of themselves to another program. Once attached to the host program, the vi-ruses then look for other programs to "infect". In this way, the virus can spread quickly throughout a hard disk or an entire organization when it in-fects a LAN or a multi-user system. The timing of the attack can be linked to a number of situations, including a certain time or date, the presence of a particular file, the security level of the user, and the number of times a fileis used. Likewise, the mode of attack varies. So called "benign" or the harmless viruses might simply display a message, like the one that infected IBM's main computer system last Christmas with a season' s greeting. Ma-lignant or the harmful viruses are designed to damage the system. The attack is to wipe out data, to delete files, or to format the hard disk. There are several kinds of anti-virus software providing the services for prevent the vi-rus from attacking your computer. So you should install the anti-virus soft-ware before your access to the Internet. It will be no use to install the soft-ware after you' ve got infected.

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1 What is a“benign”virus?

A．It is a virus that causes great damage．

B．It is a virus that once infected the IBM’s computer system．

C．It is a virus that carries a Christmas greeting．

D．It is a virus that causes no harm to the computer systems．

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2 What can a“malignant”virus do to your computer?

A．It Can cause no damages at all．

B．It Can cause damages to the computer systems．

C．It Can copy your files in computers．

D．It Can format your hard drive．

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3 根据下面资料，回答题
Technology has been an encouragement of historical change. It acted as such a force in Eng-land beginning in the eighteenth century, and across the entire Western World in the nineteenth.
Rapid advances were made in the use of scientific findings in the manufacture (制造) of goods,which has changed ideas about work. One of the first changes was that other forms of energy have taken the place of human power. Along with this came the increased use of machines to manufac-ture products in less time.
People also developed machines that could produce the same parts for a product: each nail was exactly like every other nail, meaning that each nail could be changed for every other nail. This means that goods could be mass produced, though mass production required breaking production down into smaller and smaller tasks.
Once this was done, workers no longer started on the product and labored to complete it. In-stead, they might work only one thousandth of it, other workers completing their own parts in cer-tain order. There is nothing strange about this manufacturing work by today´ s standards. Highly skilled workers were unable to compare with the new production techniques, as mass production al-lowed goods of high standard to be produced in greater number than could ever be done by hand.
But the skilled worker wasn´ t the only loser, the common workers lost too. Similar changes forced farmers away. The increased mechanization(机械化) Of agriculture freed masses of workers from ploughing the land and harvesting its crops. They had little choice but to stream toward the rapidly developing industrial centers. Increasingly, standards were set by machines. Workers no longer owned their own tools, their skill was no longer valued, and pride in their work was no longer pos-sible. Workers fed, looked after and repaired the machines that could work faster than humans at greatly reduced cost.
In this passage, which of the following is NOT considered as a change caused by the use of scientific findings in the production of goods?

A．Other forms of energy have taken the place of human power．

B．The increased exploitation of workers in the l9th century．

C．The increased use of machines to make products in less time．

D．The use of machines producing parts of the same standard．

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