A
E-mail systems at thousands of companies and government offices around the world were attacked by a virus(病毒)called “Melissa” that disguises(伪装)itself as an “important message”from a friend. In spite of a weekend of warnings，more than 50 000 computers at about 100 places around the world have been attacked by the virus，computer security experts said on Monday.
The virus began to show up last Friday and spread rapidly on Monday by making computers fire off dozens of infected(被传染的)e-mails. Although the virus causes no serious damage to a computer，its effect was far reaching.
To make matters worse，a similar virus called “Papa” was discovered on Monday. Papa is programmed to send out even more infected e-mails than Melissa.
The Melissa virus comes in the form of an e-mail，usually containing the subject line“Important Message”. It appears to be from a friend. The body of the e-mail message says，“Here is that document you asked for...,don’t show it to anyone else.” Attached(附)to the message is a document file.
Once the user opens that file，the virus digs into the user’s address book and sends infected documents to the first 50 addresses. E-mails from the Papa virus include an attached spreadsheet(电子数据文件)file. When the user opens that file，the virus sends 60 infected e-mails.
The reason why this is spreading so fast is that you are getting it from people you know. You should never open documents or attachments from people you don’t know. People who get an unexpected e-mail with the “important message” subject line should delete it immediately and not open the message.
21.Thousands of computers were attacked by the Melissa virus _______________.
A. covered with an important message
B. under cover of a message needing immediate attention
C. under the clothes of an important e-mail
D. with a beautiful coat
22.The Melissa virus made a computer _____________________.
A. receive tens of bad e-mails
B. fire at many sick e-mail messages
C. send out scores of infected messages
D. burn with a fire because of many infected e-mails
23.After the attack by the Melissa virus a computer ________________.
A. was slightly damaged
B. became entirely out of order
C. could not send out any e-mail any longer
D. would have to be thrown away
24.If you opened an infected file by Melissa virus，the virus would ______________.
A. damage the user’s address book at once
B. soon spread through the user’s list of address
C. let the first 50 addresses go out of the computer
D. change the user’s address book in the computer
