计算机专业英语Unit-9

1、Unit 9 Computer VirusText 1 Virus IntroductionExercises1.Multiple choices.(1)A virus is a ( A ).A.programB. computerC.bad manD. beastA virus is a program that reproduces its own code by(ABC).A.addi ng to the end of a fileB.inserting into the middle of a fileC.simply placi ng a poin terD.replaci ng a

2、no ther program(AD ) is a type of executable file .A.COM fileB. TXT fileC.JPG fileD. EXE file(4) Similar to viruses, you can also find malicious code in ( ABC ).A. Troja n HorsesB. wormsC. logic bombsD.Microsoft Word Docume nts2. Fill in the bla nks.(1) A virus is a program that reproduces its own c

3、ode by attaching itself to other executable files in such a way that the virus code is executed when the infected executable file is executed .(2) To attach might mean physically adding to the end of a file, in serting into the middle of a file, or simply placing a poin ter to a differe nt locati on

4、 on the disk somewhere where the virus can find it.(3) Similar to viruses, you can also find malicious code in Trojan Horses, worms, and logic bombs.3. Tran slate and an alyze the followi ng senten ces.(1) These self-replicati ng codes, whe n caused by some event, may do a pote ntially harmful act t

5、o your computer.句子组成：when引导时间状语从句做插入语，当 的时候 .翻译：当这些自复制代码被一些事件触发时，或许会做出一些对你的电脑有潜在危害的行为.(2) M ore recently, scripts written for Internet web sites and/or included in E-mail can also be executed and in fected.句子组成： scripts written省略的定语从句完整形式 scripts which were writtened .翻译：现在，为网站编写的或者包括在E-mail中的脚本也能够被

6、执行和感染。4. Readi ng comprehe nsion.Viruses can infect any type of executable code, not just the files that are commonly called“ program files . Viruses can be spread by:? Executable code in the boot sector of in fected floppy disks? Executable code in the system area of in fected hard drives? Word pro

7、cess ing and spreadsheet docume nts that use in fected macros In fected HTML docume nts that contain JavaScript or other types of executable codeSince virus code must be executed (run) to have any effect, files that the computer treats as pure data are safe. This includes graphics and sound files su

8、ch as .gif, .jpg, .mp3, .wav, etc., as well as plai n text in .txt files. For example, just viewi ng picture files won't i nfect your computer with a virus. The virus code has to be in a form, such as an .exe program file or a Word .doc file, that the computer will actually try to execute.An swe

9、r the followi ng questi ons accord ing to the article above.(1) What kind of files can be in fected by a virus?A virus can infect the executable files such as .exe oror .doc files,etc.(2) How about viruses can be spread?Executable code in the boot sector of infected floppy disks or in the system are

10、a of infected hard drives, word processing and spreadsheet documents that use infected macros In fected HTML docume nts that contain JavaScript or other types of executable code.Text 2 Virus Behavior -Infection PhaseExercises1.Multiple choices.(1)Viruses all have two phases to their execution, the (

11、 A ) and the ( C ).A.infection phaseB. delete phaseC.attack phaseD. create phase(ABCD ) maybe a certain cause that some viruses infect upon.A.a dayB. a timeC.an exter nal eve nt on your PCD. a coun ter withi n the virusMany viruses go reside nt in the memory like a ( C ).A.exe fileB.fileC.tsr progra

12、mD.data fileYou want to ( ABC )maybe wake up a virus that has residented in memoryA.copy a fileB. access a disketteC.execute a programD. delete a fileSome viruses use ( A )and ( B ) tech niq ues to hide their existe nee.A.stealthB.polymorphicC.quickly spreadD.replace a part of system software2. Fill

13、 in the bla nks.(1) Viruses come in a great many differe nt forms, but they all pote ntially have two phases to their executi on, the infection phase and the attact phase.(2) For those not old eno ugh to remember tsr, they were programs that executed un der system but stayed in memory in stead of en

14、ding.(3) Note that worms often take the opposite approach and spread as fast as possible.3. Tran slate and an alyze the followi ng senten ces.(1) When the virus executes it has the pote ntial to infect other programs.句子组成： when引导时间状语从句当，时.翻译：.(2) Some viruses infect other programs each time they are

15、 executed; other viruses infect only upon a certa in cause.句子组成： someother弓丨导两个并歹U句子，一些其他.。翻译：原因下才能感染其他程序.(3) Reside nt viruses freque ntly take over portions of the system software on the PC to hide their existe nee.句子组成：to hide their existenee 不定式做目 的状语 take over 代替.翻译：驻留内存病毒常常代替PC系统文件的一局部来掩饰它的存在4

16、. Readi ng comprehe nsion.Polymorphic viruses use encryption (密码术)or other methods to change how they look. This strategy of changing their appearanee helps to defeat antivirus scanning software. Stealth viruses attempt to hide any modifications they have made from antivirus scanning software. For e

17、xample, stealth viruses sometimes substitute unaltered files and directory table entries for the virus-altered on es, in an attempt to fool an tivirus sca nning software. Fast in fector viruses are capable of in fecti ng any file which is opened, rather than only executed files. Slow infectors only

18、modify files as the files are being created or altered for legitimate reasons, a practice which fools some antivirus software. Sparse in fectors only infect at certa in in tervals dictated by their program min g, lesse ning their cha nee of creating suspicion on the part of the user.Choose the best

19、an swer.(1) How can polymorphic viruses defeat an tivirus sca nning software?(B)A. reside nt in memoryB. use en crypti onC. hide in other programsD. use the un altered files to replace the virus-altered ones(2) How can stealth viruses fool an tivirus sca nning software?(C)A. reside nt in memoryB. us

20、e en crypti onC. hide in other programsD. use the un altered files to replace the virus-altered onesUnit 9 Computer Virus(3) Which kind of virus can only alter files, as the files are being created or altered for legitimate reas on s?(D)A. polymorphic virusB. stealth virusC. fast virus D. slow virus

21、(4) A few of viruses on ly infect at certa in in tervals dictated by their program ming, because of _?(A)A. Don 'let user no tice them.B. They wait for some special programs to in fect.C. No special reas on.D. They want to cha nge how they look.Text 3 Virus Behavior Attack PhaseExercises1. Multi

22、ple choices.(1) Many viruses do harmful things such as ( ABCD ).A. deleti ng filesB.cha ngingran dom data on your diskC.simulati ng typosD.slowing your PC dow n(2) Viruses can delay their attack for ( ABCD ).A. daysB.weeksC.mon thsD.yearsIf a virus simplyreproduce andhave no cause for an attack phas

23、e, but it willstill(AB ) without your permissi on.A. steali ng storageB. pilfer CPU cyclesC. delete filesC. play musicSome viruses, withno attack phase, often damage the programs or disks they infectbecause they( AB )A. have bugs in themC. steal storageB. contain poor quality codeD. show messages on

24、 your scree n2. Fill in the bla nks.(1) Many viruses do un pleasa nt things such as deleting files or changing random data on your disk.(2) Most viruses have bugs in them and these bugs often cause unintended negative side effects.(3) In additi on, even if the virus is perfect, it still steals syste

25、m resources.(4) The attack phase is option al, many viruses simply reproduce and have no cause for an attack phase.(5) An example, one of the most com mon past viruses, Stoned, is not inten ti on ally harmful.3. Tran slate and an alyze the follow ing sentences.(1) Just as the infection phase can be

26、caused by some event, the attack phase also has itsown cause.句子组成： as引导状语从句 .翻译：如同感染阶段需要一些事件触发一样，攻击阶段也有它自己的触发条件.(2) In addition, even if the virus is perfect, it still steals system resources.句子组成： even if 即使，引导条件状语从句；in addition 另夕卜.翻译：此外，即使病毒设计完美，它仍会盗用系统资源。(3) This is made worse si nee viruses tha

27、t "just in fect," with no attack phase, ofte n damage the programs or disks they infect.句子组成： since弓丨导原因状语从句with no attact phase 插入语.翻译：这反而更有害.(4) The original virus tried to hide its own code in an area of 1.2MB diskettes that resulted in corruption of the entire diskette (this bug was fi

28、xed in later versions of the virus).句子组成：that弓丨导主语从句表示 the originalin an area of 1.2MB diskettes.翻译：.4. Readi ng comprehe nsion.When you start a program that's infected by a virus, the virus code will execute (run) and try and infect other programs. This can infect the same computer or other com

29、puters connected to it on a n etwork. The n ewly in fected programs will try to in fectmore programs and computers. When youshare a copy of an infected file with other computer users, opening the file may also infect their computers; and files from those computers may spread the infection to yet mor

30、e computers. If your computer is infected with a boot sector virus, the virus tries to write copies of itself to the system areas of floppy disks and hard disks. Then the in fected floppy disks may infect other computers that boot from them, and then the virus on the computer will try to infect more

31、 floppies inserted into it.An swer the followi ng two questio ns accord ing to the article above.(1) Did you meet any viruses before?(2) If you have met a virus, do you remember how the virus in fected your computer?Text 4 Number of VirusesExercisesi.Multiple choices.(1)A.C.A.B.C.7500D. 50000What ma

32、ke it is difficult to agree on how to count viruses?(ABCD) new virus arise from an existing virussome viruses can create differe nt versions whe n they infect other programs some viruses can use polymorphic tech niqueIn 2000, the number of viruses topped ( D )500B. 1000D.A.just a trivial cha nge may

33、 create a new virusThe Whale will create ( D ) differe nt vers ions of itself whe n it in fects files.30B. 3130B.C.D.32DNow, about ( C ) the wild.33differe nt viruses acco unt for all the viruses that actually spread inA. 30B.150C. 180 D. 500002. Fill in the bla nks.(1) In late 1992, estimates were

34、ranging from 1,000 to 2,300 viruses.(2) But, this is a trivial cha nge that can be done in less tha n two minu tes result ing in yet ano ther "n ew" virus.(3) Another problem comes from viruses that try to conceal themselves from scanners by mutati ng.3. Tran slate and an alyze the followi

35、 ng senten ces.(1) The con fusi on exists partly because it's difficult to agree on how to count viruses.句子结构：it 'difficult中it为形式主语代替后面真正的主语to agree on.翻译：由于在怎样计算病毒上很难达成一致，所以现在还存在一些混乱(2) But, this is a trivial change that can be done in less than two minutes resulting in yet ano ther "

36、new" virus.句子结构：that弓丨导定语从句修饰cha nge.翻译：但是，一个在两分钟内可以完成的细微的改动就产生了一种“新病毒.(3) Many of the large nu mber of viruses known to exist have not bee n detected in the wild but probably exist only in some on e's virus collectio n.句子结构： notbut 不是而是.翻译：彳.(4) Although the actual nu mber of viruses will

37、probably con ti nue to be hotly debated, what is clear is that the total nu mber of viruses is in creas ing, although the active viruses not quite as rapidly as the nu mbers might suggest.句子结构： although 表转折，连接词，引导句子.翻译：毒的总数在增加。4. Readi ng comprehe nsion.Viruses are software programs; the actual effe

38、ct of a virus depe nds on how it was programmed by the person who wrote the virus.Some viruses are designed to overwrite boot sectors and interfere with your computer's operation (boot viruses), others damage your computers memory operati on the n try and spread themselves around by picking up e

39、-mail or network addresses off your computer (worm viruses). Still others will wipe files from the hard drive and destroy system files (Troja n viruses) and fin ally there are ones that i nfect docume nt files,How Serious are Viruses? electr onic spreadsheets and databases of several popular softwar

40、e packages (Macro viruses).Viruses can't do any damage to hardware: they won't melt dow n your CPU, bur n out your hard drive, cause your mon itor to explode, etc. Warnings about viruses that will physically destroy your computer are usually hoaxes, not legitimate virus warnin gs.Make some c

41、hoices after readi ng the article above. The actual effect of a virus depends on ( A ).A. the pers on who wrote the virusB. how much your computer isC. how to use your computerD. a special cause(2) What kind of virus may overwrite boot sectors and interfere with your computer's operati on (boot

42、viruses), others damage?( A )A. boot virusB. worm virusC. Troja n virusD. Macro virus(3) A macro virus can not infect ( C ).A. docume nt filesB. electr onic spreadsheetsC. overwrite boot sectorsD. databases of several popular software packagesText 5 How Serious are Viruses?Exercises1. Fill in the bl

43、a nks.(1) While serious if you have one, viruses are only one way your data can be damaged.(2) It's still clear that there are many dan gerous occurre nces of data corruption from causes other tha n from viruses.(3) One just has to take protective steps with an ti-virus software and use some com

44、 mon sense whe n deali ng with unknown files.(4) Because viruses and worms are deliberately written to invade and possibly damage your PC, they are the most difficult threat to guard_aga in st.2. Tran slate and an alyze the followi ng senten ces.(1) While serious if you have one, viruses are only one way your data can be damaged.句子结构： while 引导原因状语从句，表转折关系.翻译：破坏的其中一种方式 .(2) It just mea ns that it's foolish to spe nd much money and time on address ing the threat ofviruses if you've done nothing about the other more likely threats to your files. 句子