12. （ ）, executable code that, when run by someone, infects other executable code in a computer. A. Computer Security B. Digital signatures C. Computer virus D. none of the above ...

7. （ ）:In encryption, a two-key system in which the key used to lock data is made public, so everyone can "lock".A second private key is used to unlock or decrypt. A. Asymmetric key B. Symmetric key C. Coputer virus D. Digital signa...

2. （ ） (Joint Photographic Experts Group), standard for compressing continuous-tone still pictures. It does not handle black-and-white images, nor does it handle motion picture compression. A. JPEG B. MPEG C. MIDI D. none of the abo...

7. To access the Web, users require a Web browser ,which is the software program used to access the World Wide Web.（ ） A. 错误 B. 正确 ...

2. A file is a collection of relation fields.（ ） A. 错误 B. 正确 ...

17. （ ）, interface that enables dissimilar networks to communicate with one another. A. Gateway B. Bridge C. Bandwidth D. none of the above ...

12. （ ）, software used in corporate networks (intranets and extranets) to prevent unauthorized people from accessing the network. A. Firewall B. Modem C. Hypertext D. TCP ...

7. （ ）, short for modulator/demodulator, device that converts digital signals into a representation of analog form(modulation) to send over phone lines;a receiving modem then converts the analog signal back to a digital signal(demodulat...

2. （ ） controls how you enter data or instructions and how information is displayed on the computer screen. A. User interface B. Language translators C. Utilities programs D. System software ...

7. A traditional private WAN can be expensive to build and manage.（ ） A. 错误 B. 正确 ...