proper memory management and TCP/IP networking. Mac OS (Machintosh Operating System)supports multitasking and networking and has a highly praised graphical user interface.Multimedia capabilities of this operating system allow Macintosh users to integrate video clip,stereo sound,and animated sequences with conventional text and graphics software. ()Tell whether the following statements are true(T)or false(F)according to the passage A,(根据上文的内容判断下列句子的正误。15分，每题3分】 1.Personal computer software is dependent on specific operating systems and machines. () 2.DOS can only work with 32-bit microprocessor. 3.Windows is the 32-bit operating system with networking capability and Internet access. 4.Unix is an interactive,multi-user,multitasking operating system. () 5.The Linux operating system is free.It is the modified version of Unix running on PCs. () Passage B A computer virus is a computer program that is created to make and spread copies of itself.The program may however also be designed to have other effects on the systems it infects,ranging from the annoying to the disastrous. Virus attacks are growing rapidly these days.According to BusinessWeek,the 76,404 attacks reported in the first half of 2003 nearly match previous year's total number.As new antivirus tools are more powerful than before,the virus writers are getting a lot smarter with newer and creative ways to attack network systems.Let's first examine some common virus types: Basic Virus -a piece of software code that is developed to attack computers and network systems via email or Internet connections.It quickly replicates itself and gradually attaches to files,programs or the hard drive. Trojan Horses-This is a program that doesn't replicate when entering a system but can be effectively used to open 'back doors.'Trojan Horses allow hackers to take control over a particular system or to steal very important data. 1433proper memory management and TCP/IP networking. Mac OS (Machintosh Operating System) supports multitasking and networking and has a highly praised graphical user interface. Multimedia capabilities of this operating system allow Macintosh users to integrate video clip，stereo sound，and animated sequences with conventional text and graphics software. (二)Tell whether the following statements are true(T) or false(F) according to the passage A.(根据上文的内容判断下列句子的正误。15分，每题 3分) 1. Personal computer software is dependent on specific operating systems and machines. ( ) 2. DOS can only work with 32-bit microprocessor. ( ) 3. Windows is the 32-bit operating system with networking capability and Internet access. ( ) 4. Unix is an interactive, multi-user, multitasking operating system. ( ) 5. The Linux operating system is free. It is the modified version of Unix running on PCs. ( ) Passage B Acomputer virus is a computer program that is created to make and spread copies of itself. The program may however also be designed to have other effects on the systems it infects，ranging from the annoying to the disastrous. Virus attacks are growing rapidly these days. According to BusinessWeek, the 76，404 attacks reported in the first half of 2003 nearly match previous year's total number.As new antivirus tools are more powerful than before，the virus writers are getting a lot smarter with newer and creative ways to attack network systems. Let’s first examine some common virus types; Basic Virus一 a piece of software code that is developed to attack computers and network systems via email or Internet connections. It quickly replicates itself and gradually attaches to files，programs or the hard drive. Trojan Horses一 This is a program that doesn’t replicate when entering a system but can be effectively used to open‘back doors.’Trojan Horses allow hackers to take control over a particular system or to steal very important data. 1433