In today's world, we rely on computers as never before. They are used for everything from

In today's world, we rely on computers as never before. They are used for everything from ordering a pizza to running hospitals and military defense systems. Banking and credit card information is stored and accessed by computers. So what happens when a computer gets infected with a virus? One effect is that people's access to their e-mail accounts is cut off. A more serious possible consequence is that billions of dollars could be lost.
A virus is a computer program that copies itself onto other programs and infects them. Similar to an easily spread disease, a computer virus goes from computer to computer, either adding to or changing the tasks a program is designed to do.
The first computer viruses were created in the mid '80s and had varying effects. Some caused files to be deleted, or made the letters on the screen appear to fall off. Others displayed a specific message once the computer was turned on.
Viruses today are much more widespread and dangerous than ever before. Perhaps the most damaging to date has been the I Love You virus. I Love You appeared in May 2000 and has possibly been the most destructive virus in terms of monetary loss.
The virus is released when an attachment to a fake e-mail message is opened. By changing the names of files on computers, I Love You makes them difficult to access. It also searches for important personal information, including passwords, which it sends to a web site for others to see.
It is estimated that more than 45 million people in 20 countries have had their computers infected by the I Love You virus. Some say the cost of repair and lost business has been more than US$10 billion.
If you own a computer, it is important to keep it in good health by installing an anti-virus program. If updated frequently, it will protect your e-mail access--not to mention your wallet.
51.What does virus mean in the article?
A. An easily spread disease.
B. A contagious (传染的) computer program.
C. An extremely small organism (生物) which causes disease.
D. A parasite (寄生虫) in computer.
52. How does I Love You virus spread?
A. It is spread when an e-mail account is opened.
B. It is spread through on-line chatting.
C. It is spread through e-mail.
D. It spreads from web site to web site.
53. Which of the following is one of the damages brought by I Love You virus?
A. It deletes files. B. It automatically turns on computers.
C. It automatically turns off computers. D. It makes it difficult to access files.
54. Which of the following is the best way to guard against virus?
A. To load an up-to-date anti-virus program into our computer
B. Not to use an e-mail account.
C. To upgrade our computer. D. Not to use the Internet.
55. What is the purpose of the article?
A. To warn us against virus.
B. To remind us the importance of being healthy.
C. To stress the importance of computer.
D. To alert us to economic loss. B

(答案→)B 解析：

就是这个解释