2016年12月四级真题第三套段落匹配题SectionBDirections:Inthissection,youaregoingtoreadapassagewithtenstatementsattachedtoit.Eachstatementcontainsinformationgiveninoneoftheparagraphs.Identifytheparagraphfromwhichtheinformationisderived.Youmaychooseaparagraphmorethanonce.Eachparagraphismarkedwithaletter.AnswerthequestionsbymarkingthecorrespondingletteronAnswerSheet2.CanBurglarsJamYourWirelessSecuritySystem?A.Anyproductthatpromisestoprotectyourhomedeservescarefulexamination.Soitisn’tsurprisingthatyou’11findplentyofstrongopinionsaboutthepotentialvulnerabilitiesofpopularhome—securitysystems.B.Themostlikelytypeofburglary(人室盗窃)byfaristheunsophisticatedcrimeofopportunity,usuallyinvolvingabrokenwindoworsomeforcedentry.AccordingtotheFB1.crimesliketheseaccountedforroughlytwo.thirdsofallhouseholdburglariesintheUSin2013.Thewidemajorityoftherestwereillegal.unforcedentriesthatresultedfromsomethinglikeawindowbeingleftopen.TheoddsofacriminalusingtechnicalmeanstobypassasecuritysystemaresosmallthattheFBIdoesn’teventrackthosestatistics.C.Oneofthemaintheoreticalhome—securityconcernsiswhetherornotagivensystemisvulnerabletobeingblockedfromworkingaltogether.Withwiredsetups,thefearisthataburglar(人室盗贼)mightbeabletoshutyoursystemdownsimplybycuttingtherightcable.Withawirelesssetup.youstickbattery—poweredsensorsuparoundyourhomethatkeepaneyeonwindows。doors,motion,andmore.Iftheydetectsomethingwrongwhilethesystemisarmed.they’lltransmitawirelessaleftsignaltoabasestationthatwillthenraisethealarm.Thatapproachwilleliminatemostcord—cuttingconcerns--butwhatabouttheirwirelessequivalent,jamming?withthefightdevicetunedtothefightfrequency,what’stostopathieffromjammingyoursetupandblockingthatalertsignalfromeverreachingthebasestation?D.Jammingconcernsarenothingnew,andthey’renotuniquetosecuritysystems.Anydevicethat’sbuilttoreceiveawirelesssignalataspecificfrequencycanbeoverwhelmedbyastrongersignalcominginonthesamefrequency.Forcomparison.1et’ssayyouwantedto“jam”aconversationbetweentwopeople—allyou’dneedtodoisyellinthelistener’sear.E)Securitydevicesarerequiredtolistthefrequenciestheybroadcaston—matmeansthatapotentialthiefcanfindwhattheyneedtoknowwithminimalGoogling.Theywill.however.needtoknowwhatsystemthey’relookingfor.Ifyouhaveasigninyouryarddeclaringwhatsetupyouuse,that’dpointthemintherightdirection,thoughatthatpoint,we’retalkingaboutahighlytargeted,semi—sophisticatedattack,andnotthesortofforced—entryattackthatmakesupthemajorityofburglaries.It’seasiertofindandacquirejammingequipmentforsomefrequenciesthanitisforothers.F)Wirelesssecurityproviderswilloftentakestepstohelpcombatthethreatofjammingattacks.SimpliSafe,winnerofourEditors’Choicedistinction.utilizesaspecialsystemthat’scapableofseparatingincidentalRFinterferencefromtargetedjammingattacks.Whenthesystemthinksit’sbeingjammed,it’llnotifyyouviapushalert(推送警报).Fromthere,it’suptoyoutosoundthealarmmanually.G)SimpliSafewassingledoutinonerecentarticleonjamming,completewithavideoshowingtheentiresystembeingeffectivelybypassedwithhandheldjammingequipment.AftertakingappropriatemeasurestocontaintheRFinterferencetoourtestlab,wetestedtheattackoutforourselves,andwereabletoverifythatit’spossiblewiththerightequipment.However.wealsoverifiedthatSimpliSafe’santi-jammingsystemworks.Itcaughtusintheact,sentanalerttomysmartphone,andalsolistedourRFinterferenceonthesystem’seventlog.Theteambehindthearticleandvideoinquestionmakenomentionofthesystem,orwhetherornotitdetectedthem.H)Weliketheuniquenatureofthatsoftware.Itmeansthatathieflikelywouldn’tbeabletoGooglehowthesystemworks.thenfigureoutawayaroundit.Eveniftheycould,SimpliSafeclaimsthatitssystemisalwaysevolving,andthatitvariesslightlyfromsystemtosystem,whichmeanstherewouldn’tbeauniversalmagicformulaforcrackingit.Othersystemsalsoseemconfidentonthesubjectofjamming.TheteamatFrontpointaddressestheissueinablogonitssite,citingtheirownjamprotectionsoftwareandclaimingthattherearen’tanydocumentedcasesofasuccessfuljamattacksincethecompanybeganofferingwirelesssecuritysensorsinthel980s.I)Jammingattacksareabsolutelypossible.Assaidbefore.withthefightequipmentandtherightknow—how,it’spossibletojamanywirelesstransmission.Buthowprobableisitthatsomeonewillsuccessfullyjamtheirwayintoyourhomeandstealyourstuff?J)Let’simaginethatyouliveinasmallhomewithawirelesssecuritysetupthatoffersafunctionalanti—jammingsystem.First,athiefisgoingtoneedtotargetyourhome,specifically.Then,he’sgoingtoneedtoknowthetechnicaldetailsofyoursystemandacquirethespecificequipmentnecessaryforjammingyourspecificsetup.Presumably,youkeepyourdoorslockedatnightandwhileyou’reaway,sothethiefwillstillneedtobreakin.Thatmeansdefeatingthelocksomehow,orbreakingawindow.He’11needtobejammingyouatthispoint,asabrokenwindoworopeneddoorwouldnormallyreleasethealarm.S0,too,wouldthemotiondetectorsinyourhome,sothethiefwillneedtocontinuejammingoncehe’sinsideandsearchingforthingstosteal.However.he’11needtodosowithouttrippingtheanti-jammingsystem,thedetailsofwhichhealmostcertainlydoesnothaveaccessto.K)Attheendoftheday,thesekindsofsystemsareprimarilydesignedtoprotectagainstthesortofopportunisticsmash—and—grabattackthatmakesupthemajorityofburglaries.They’realsoonlyasinglelayerinwhatshouldideallybeamany—sidedapproachtosecuringyourhome,onethatincludescommonsensethingslikesoundlocksandproperexteriorlightingatnight.Nosystemisimpenetrable,andnonecanpromisetoeliminatetheworstcasecompletely.Everyoneofthemhasvulnerabilitiesthataknowledgeablethiefcouldtheoreticallyexploit.Agoodsystemisonethatkeepsthatworst—casesettingasimprobableaspossiblewhilealsoofferingstrongprotectionintheeventofaless-extraordinaryattack.--1.Itispossibleforburglarstomakejammingattackswiththenecessaryequipmentandskill.--2.Interferingwithawirelesssecuritysystemissimilartointerferingwithaconversation.--3.Aburglarhastocontinuouslyjamthewirelesssecuritydevicetoavoidtriggeringthealarm,bothinsideandoutsidethehouse.--4.SimpliSafeprovidesdevicesthatareabletodistinguishincidentalradiointerferencefromtargetedjammingattacks.--5.Onlyaverysmallproportionofburglariesarecommittedbytechnicalmeans.--6.ItisdifficulttocrackSimpliSafeasitssystemkeepschanging.--7.Wirelessdeviceswilltransmitsignalssoastoactivatethealarmoncesomethingwrongisdetected.--8.Differentmeasuresshouldbetakentoprotectone’shomefromburglaryinadditiontothewirelesssecuritysystem.--9.SimpliSafe’sdevicecansendawarningtothehouseowner’scellphone.--10.Burglarscaneasilygetasecuritydevice’sfrequencybyInternetsearch.
2016年12月四级真题第三套段落匹配题SectionBDirections:Inthissection,youaregoingtoreadapassagewithtenstatementsattachedtoit.Eachstatementcontainsinformationgiveninoneoftheparagraphs.Identifytheparagraphfromwhichtheinformationisderived.Youmaychooseaparagraphmorethanonce.Eachparagraphismarkedwithaletter.AnswerthequestionsbymarkingthecorrespondingletteronAnswerSheet2.CanBurglarsJamYourWirelessSecuritySystem?A.Anyproductthatpromisestoprotectyourhomedeservescarefulexamination.Soitisn’tsurprisingthatyou’11findplentyofstrongopinionsaboutthepotentialvulnerabilitiesofpopularhome—securitysystems.B.Themostlikelytypeofburglary(人室盗窃)byfaristheunsophisticatedcrimeofopportunity,usuallyinvolvingabrokenwindoworsomeforcedentry.AccordingtotheFB1.crimesliketheseaccountedforroughlytwo.thirdsofallhouseholdburglariesintheUSin2013.Thewidemajorityoftherestwereillegal.unforcedentriesthatresultedfromsomethinglikeawindowbeingleftopen.TheoddsofacriminalusingtechnicalmeanstobypassasecuritysystemaresosmallthattheFBIdoesn’teventrackthosestatistics.C.Oneofthemaintheoreticalhome—securityconcernsiswhetherornotagivensystemisvulnerabletobeingblockedfromworkingaltogether.Withwiredsetups,thefearisthataburglar(人室盗贼)mightbeabletoshutyoursystemdownsimplybycuttingtherightcable.Withawirelesssetup.youstickbattery—poweredsensorsuparoundyourhomethatkeepaneyeonwindows。doors,motion,andmore.Iftheydetectsomethingwrongwhilethesystemisarmed.they’lltransmitawirelessaleftsignaltoabasestationthatwillthenraisethealarm.Thatapproachwilleliminatemostcord—cuttingconcerns--butwhatabouttheirwirelessequivalent,jamming?withthefightdevicetunedtothefightfrequency,what’stostopathieffromjammingyoursetupandblockingthatalertsignalfromeverreachingthebasestation?D.Jammingconcernsarenothingnew,andthey’renotuniquetosecuritysystems.Anydevicethat’sbuilttoreceiveawirelesssignalataspecificfrequencycanbeoverwhelmedbyastrongersignalcominginonthesamefrequency.Forcomparison.1et’ssayyouwantedto“jam”aconversationbetweentwopeople—allyou’dneedtodoisyellinthelistener’sear.E)Securitydevicesarerequiredtolistthefrequenciestheybroadcaston—matmeansthatapotentialthiefcanfindwhattheyneedtoknowwithminimalGoogling.Theywill.however.needtoknowwhatsystemthey’relookingfor.Ifyouhaveasigninyouryarddeclaringwhatsetupyouuse,that’dpointthemintherightdirection,thoughatthatpoint,we’retalkingaboutahighlytargeted,semi—sophisticatedattack,andnotthesortofforced—entryattackthatmakesupthemajorityofburglaries.It’seasiertofindandacquirejammingequipmentforsomefrequenciesthanitisforothers.F)Wirelesssecurityproviderswilloftentakestepstohelpcombatthethreatofjammingattacks.SimpliSafe,winnerofourEditors’Choicedistinction.utilizesaspecialsystemthat’scapableofseparatingincidentalRFinterferencefromtargetedjammingattacks.Whenthesystemthinksit’sbeingjammed,it’llnotifyyouviapushalert(推送警报).Fromthere,it’suptoyoutosoundthealarmmanually.G)SimpliSafewassingledoutinonerecentarticleonjamming,completewithavideoshowingtheentiresystembeingeffectivelybypassedwithhandheldjammingequipment.AftertakingappropriatemeasurestocontaintheRFinterferencetoourtestlab,wetestedtheattackoutforourselves,andwereabletoverifythatit’spossiblewiththerightequipment.However.wealsoverifiedthatSimpliSafe’santi-jammingsystemworks.Itcaughtusintheact,sentanalerttomysmartphone,andalsolistedourRFinterferenceonthesystem’seventlog.Theteambehindthearticleandvideoinquestionmakenomentionofthesystem,orwhetherornotitdetectedthem.H)Weliketheuniquenatureofthatsoftware.Itmeansthatathieflikelywouldn’tbeabletoGooglehowthesystemworks.thenfigureoutawayaroundit.Eveniftheycould,SimpliSafeclaimsthatitssystemisalwaysevolving,andthatitvariesslightlyfromsystemtosystem,whichmeanstherewouldn’tbeauniversalmagicformulaforcrackingit.Othersystemsalsoseemconfidentonthesubjectofjamming.TheteamatFrontpointaddressestheissueinablogonitssite,citingtheirownjamprotectionsoftwareandclaimingthattherearen’tanydocumentedcasesofasuccessfuljamattacksincethecompanybeganofferingwirelesssecuritysensorsinthel980s.I)Jammingattacksareabsolutelypossible.Assaidbefore.withthefightequipmentandtherightknow—how,it’spossibletojamanywirelesstransmission.Buthowprobableisitthatsomeonewillsuccessfullyjamtheirwayintoyourhomeandstealyourstuff?J)Let’simaginethatyouliveinasmallhomewithawirelesssecuritysetupthatoffersafunctionalanti—jammingsystem.First,athiefisgoingtoneedtotargetyourhome,specifically.Then,he’sgoingtoneedtoknowthetechnicaldetailsofyoursystemandacquirethespecificequipmentnecessaryforjammingyourspecificsetup.Presumably,youkeepyourdoorslockedatnightandwhileyou’reaway,sothethiefwillstillneedtobreakin.Thatmeansdefeatingthelocksomehow,orbreakingawindow.He’11needtobejammingyouatthispoint,asabrokenwindoworopeneddoorwouldnormallyreleasethealarm.S0,too,wouldthemotiondetectorsinyourhome,sothethiefwillneedtocontinuejammingoncehe’sinsideandsearchingforthingstosteal.However.he’11needtodosowithouttrippingtheanti-jammingsystem,thedetailsofwhichhealmostcertainlydoesnothaveaccessto.K)Attheendoftheday,thesekindsofsystemsareprimarilydesignedtoprotectagainstthesortofopportunisticsmash—and—grabattackthatmakesupthemajorityofburglaries.They’realsoonlyasinglelayerinwhatshouldideallybeamany—sidedapproachtosecuringyourhome,onethatincludescommonsensethingslikesoundlocksandproperexteriorlightingatnight.Nosystemisimpenetrable,andnonecanpromisetoeliminatetheworstcasecompletely.Everyoneofthemhasvulnerabilitiesthataknowledgeablethiefcouldtheoreticallyexploit.Agoodsystemisonethatkeepsthatworst—casesettingasimprobableaspossiblewhilealsoofferingstrongprotectionintheeventofaless-extraordinaryattack.--1.Itispossibleforburglarstomakejammingattackswiththenecessaryequipmentandskill.--2.Interferingwithawirelesssecuritysystemissimilartointerferingwithaconversation.--3.Aburglarhastocontinuouslyjamthewirelesssecuritydevicetoavoidtriggeringthealarm,bothinsideandoutsidethehouse.--4.SimpliSafeprovidesdevicesthatareabletodistinguishincidentalradiointerferencefromtargetedjammingattacks.--5.Onlyaverysmallproportionofburglariesarecommittedbytechnicalmeans.--6.ItisdifficulttocrackSimpliSafeasitssystemkeepschanging.--7.Wirelessdeviceswilltransmitsignalssoastoactivatethealarmoncesomethingwrongisdetected.--8.Differentmeasuresshouldbetakentoprotectone’shomefromburglaryinadditiontothewirelesssecuritysystem.--9.SimpliSafe’sdevicecansendawarningtothehouseowner’scellphone.--10.Burglarscaneasilygetasecuritydevice’sfrequencybyInternetsearch.
如果ξ与η不相关，则（）。 A: D（ξ+η）=Dξ+Dη B: D（ξ-η）=Dξ-Dη C: D（ξη）=Dξ·Dη D: E（ξη）=Dξ·Dη
如果ξ与η不相关，则（）。 A: D（ξ+η）=Dξ+Dη B: D（ξ-η）=Dξ-Dη C: D（ξη）=Dξ·Dη D: E（ξη）=Dξ·Dη
已有定义intd=-2;，执行以下语句后的输出结果是：printf('*d(1)=%d*d(2)=%3d*d(3)=%-3d* ',d,d,d,d);printf('*d(4)=%o*d(5)=%7o*d(6)=%-7o* ',d,d,d,d);printf('*d(4)=%x*d(5)=%6x*d(6)=%-6x* ',d,d,d,d);
已有定义intd=-2;，执行以下语句后的输出结果是：printf('*d(1)=%d*d(2)=%3d*d(3)=%-3d* ',d,d,d,d);printf('*d(4)=%o*d(5)=%7o*d(6)=%-7o* ',d,d,d,d);printf('*d(4)=%x*d(5)=%6x*d(6)=%-6x* ',d,d,d,d);
圆柱螺旋弹簧的旋绕比C是（） A: d/D B: d/D C: D/d D: D/d
圆柱螺旋弹簧的旋绕比C是（） A: d/D B: d/D C: D/d D: D/d
已有定义int d= –2；执行以下语句后的输出结果是。 printf(" * d(1) =%d * d(2)= %3d * d(3) =% –3d * "，d，d，d)； printf(" * d(4) =%d * d(5)= %7d * d(6) =% –7d * "，d，d，d)；
已有定义int d= –2；执行以下语句后的输出结果是。 printf(" * d(1) =%d * d(2)= %3d * d(3) =% –3d * "，d，d，d)； printf(" * d(4) =%d * d(5)= %7d * d(6) =% –7d * "，d，d，d)；
若有说明语句：int a，b，c，* d＝＆c；，则能正确从键盘读入三个整数分别赋给变量a、b、d的语句是 ( ) A．scanf("%d%d%d"，＆a，＆b，d)； B．scanf("%d%d%d"，＆a，＆b，＆d)； C．scanf("%d %d%d"，a，b，d)； D．scanf("%d%d%d"，a，b，* d)；
若有说明语句：int a，b，c，* d＝＆c；，则能正确从键盘读入三个整数分别赋给变量a、b、d的语句是 ( ) A．scanf("%d%d%d"，＆a，＆b，d)； B．scanf("%d%d%d"，＆a，＆b，＆d)； C．scanf("%d %d%d"，a，b，d)； D．scanf("%d%d%d"，a，b，* d)；
如果要用JK触发器来实现D触发器的功能，则J=( )，K=( )。 A: D;D' B: D;D C: D';D' D: D;D
如果要用JK触发器来实现D触发器的功能，则J=( )，K=( )。 A: D;D' B: D;D C: D';D' D: D;D
20A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、120、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、130、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、140、A、B、C、D、A
20A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、120、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、130、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、A、B、C、D、140、A、B、C、D、A
下列字符之间的大小关系 A: 0>;D>;d B: d>;D>;0 C: D>;0>;d D: d>;0>;D
下列字符之间的大小关系 A: 0>;D>;d B: d>;D>;0 C: D>;0>;d D: d>;0>;D
互换行列式 $D$ 的两行（列）得到行列式 $D'$，则有（ ）. A: $D'=D$ B: $D'=2D$ C: $D'=-D$ D: $D'=0$
互换行列式 $D$ 的两行（列）得到行列式 $D'$，则有（ ）. A: $D'=D$ B: $D'=2D$ C: $D'=-D$ D: $D'=0$