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.
Whichtwowordsareclosestinmeaning?<br/><b>cycle</b><b>，</b><b>hawk</b><b>，</b><b>convey</b><b>，</b><b>extort</b><b>，</b><b>peddle</b><b>，</b><b>summon</b>
Whichtwowordsareclosestinmeaning?<br/><b>cycle</b><b>，</b><b>hawk</b><b>，</b><b>convey</b><b>，</b><b>extort</b><b>，</b><b>peddle</b><b>，</b><b>summon</b>
设A{a,b}，则P(A)×A = ( )。 A: A B: P（A） C: {<Φ,a>,<Φ,b>,<{a},a>,<{a},b>,<{b},a>,<{b},b>,<A,a>,<A,b>} D: {<a,,Φ,>,<b,,Φ,>,<a,{a}>,<b,{a}>,<a,{b}>,<b,{b}>,<a,A>,<b,A>}
设A{a,b}，则P(A)×A = ( )。 A: A B: P（A） C: {<Φ,a>,<Φ,b>,<{a},a>,<{a},b>,<{b},a>,<{b},b>,<A,a>,<A,b>} D: {<a,,Φ,>,<b,,Φ,>,<a,{a}>,<b,{a}>,<a,{b}>,<b,{b}>,<a,A>,<b,A>}
以下哪段代码可以将A,B的值互换（） A: A=A^B; B=A^B;A=A^B B: A= A^B;A=A^B;B=A^B C: B= A^B; B=A^B; A=A^B D: B=A^B; A= A^B; A= A^B
以下哪段代码可以将A,B的值互换（） A: A=A^B; B=A^B;A=A^B B: A= A^B;A=A^B;B=A^B C: B= A^B; B=A^B; A=A^B D: B=A^B; A= A^B; A= A^B
若集合A={a，b}，B={ a，b，{ a，b }}，则（）。 A: A⊆B，且A∈B B: A∈B，且B⊆A C: A⊈B，且A∉B D: A∉B，且A⊈B
若集合A={a，b}，B={ a，b，{ a，b }}，则（）。 A: A⊆B，且A∈B B: A∈B，且B⊆A C: A⊈B，且A∉B D: A∉B，且A⊈B
设论域D={a,b}，与公式[img=504x85]17d6234b6469e12.png[/img]等价的命题公式是（ ） A: (A（a）∧A（b）) → (B（a）∧B（b）) B: (A（a）→B（a）)∨(A（b）→B（b）) C: (A（a）∨A（b）) → (B（a）∨B（b）) D: (A（a）→B（a）)∧(A（b）→B（b）)
设论域D={a,b}，与公式[img=504x85]17d6234b6469e12.png[/img]等价的命题公式是（ ） A: (A（a）∧A（b）) → (B（a）∧B（b）) B: (A（a）→B（a）)∨(A（b）→B（b）) C: (A（a）∨A（b）) → (B（a）∨B（b）) D: (A（a）→B（a）)∧(A（b）→B（b）)
设论域D={a,b},与公式[img=126x21]17da63121bb0ede.png[/img]等价的命题公式是( ) A: (A(a)∧A(b)) → (B(a)∧B(b)) B: (A(a)→B(a))∨(A(b)→B(b)) C: (A(a)∨A(b)) → (B(a)∨B(b)) D: (A(a)→B(a))∧(A(b)→B(b))
设论域D={a,b},与公式[img=126x21]17da63121bb0ede.png[/img]等价的命题公式是( ) A: (A(a)∧A(b)) → (B(a)∧B(b)) B: (A(a)→B(a))∨(A(b)→B(b)) C: (A(a)∨A(b)) → (B(a)∨B(b)) D: (A(a)→B(a))∧(A(b)→B(b))
优学院: <p class="MsoNormal"> <b>一人造地球卫星到地球中心</b><b>O</b><b>的最大距离和最小距离分别是</b><b>R</b><b><sub>A</sub></b><b>和</b><b>R</b><b><sub>B</sub></b><b>．设卫星对应的角动量分别是</b><b>L</b><b><sub>A</sub></b><b>、</b><b>L</b><b><sub>B</sub></b><b>，动能分别是</b><b>E</b><b><sub>KA</sub></b><b>、</b><b>E</b><b><sub>KB</sub></b><b>，则应有</b><b> </b><b> </b><b> [ </b><b> </b><b> ]</b><b><o:p></o:p></b> </p> <p class="MsoNormal"> <b><br> </b> </p>
优学院: <p class="MsoNormal"> <b>一人造地球卫星到地球中心</b><b>O</b><b>的最大距离和最小距离分别是</b><b>R</b><b><sub>A</sub></b><b>和</b><b>R</b><b><sub>B</sub></b><b>．设卫星对应的角动量分别是</b><b>L</b><b><sub>A</sub></b><b>、</b><b>L</b><b><sub>B</sub></b><b>，动能分别是</b><b>E</b><b><sub>KA</sub></b><b>、</b><b>E</b><b><sub>KB</sub></b><b>，则应有</b><b> </b><b> </b><b> [ </b><b> </b><b> ]</b><b><o:p></o:p></b> </p> <p class="MsoNormal"> <b><br> </b> </p>
设个体域D={a，b}与公式∀x A(x)∧∀xB(x) 等价的命题公式是( ) A: (A(a)∧A(b)) ∧(B(a) ∧B(b)) B: (A(a)∨A(b)) ∧(B(a) ∨B(b)) C: (A(a)∧A(b))∨(B(a)∧B(b)) D: (A(a)∨B(a)) ∧(A(b) ∨B(b))
设个体域D={a，b}与公式∀x A(x)∧∀xB(x) 等价的命题公式是( ) A: (A(a)∧A(b)) ∧(B(a) ∧B(b)) B: (A(a)∨A(b)) ∧(B(a) ∨B(b)) C: (A(a)∧A(b))∨(B(a)∧B(b)) D: (A(a)∨B(a)) ∧(A(b) ∨B(b))
设A=ía,bý,B=í1,2,3ý,求:A×B,B×A,A×A,B×B和(A×B)∩( B×A)。
设A=ía,bý,B=í1,2,3ý,求:A×B,B×A,A×A,B×B和(A×B)∩( B×A)。