对临界区的正确论述是( )。

①临界区是指进程中实现进程互斥的那段代码

②临界区是指进程中用于实现进程同步的那段代码

③临界区是指进程中用于实现进程通信的那段代码

④临界区是指进程中用于访问共享资源的那段代码

⑤临界区是指进程中用于访问临界资源的那段代码

⑥若进程A与进程B必须互斥地进入自己的临界区，则进程A处于对应的区内时，仍有可能被进程B中断

(81)

The main function of a processor is to(68)and carry out instructions which usually consist of operation and(69). The term to measure the speed of the processor is called a Megahertz(MHz), which means million(70)per second.

(80)

(78)

The successful spread of a virus depends on how long it can()unnoticed, before its presence is made known by the activation of side-effects.

(76)

Anti- virus software protects your computer from viruses by(75)your computer's memory and disk devices.

(70)is not a peripheral component or device. The basic input device on a small computer is a(71).

A(74)is a device that enables the computer to handle sounds.

The transmission media used t0 build a LAN is(73).