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 ...

2. A backup program makes a copy of files you select.（ ） A. 错误 B. 正确 ...

17. A （ ） port is an interface that connects devices by transferring more than one bit at a time. A. serial B. parallel C. USB D. none of the above ...

12. The first computers used （ ） for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. A. vacuum tubes B. transistors C. integrated circuits D. microprocessors ...

7. （ ） are output devices that print characters, symbols, and graphics on a physical medium such as paper and a transparency file. A. Flat panel monitors B. Printers C. Keyboards D. Pointing device ...

2. （ ） performs arithmetic, comparison, and logic operations. It is one part of the CPU. A. RAM B. ROM C. CPU D. ALU ...

7. The ENIAC used thousands of vacuum tubes,which took up a lot of space and gave off a great deal of heat just like light bulbs do.（ ） A. 错误 B. 正确 ...

2. The microprocessor led to the invention of personal computers,or microcomputers.（ ） A. 错误 B. 正确 ...