2026年机械英语专项训练冲刺试卷

2026年机械英语专项训练冲刺试卷I.VocabularyandStructure(Thereare20incompletesentencesinthispart.ForeachsentencetherearefourchoicesmarkedA,B,CandD.ChoosetheONEthatbestcompletesthesentence.1pointforeach,20pointsintotal)1.Indimensioningofmechanicalparts,______referstothetotalpermissiblevariationofasizefromthenominaldimension.A.allowanceB.toleranceC.deviationD.clearance2.Whendesigningageartransmissionsystem,______gearsarecommonlyusedtotransmitmotionbetweentwointersectingshafts.A.spurB.helicalC.bevelD.worm3.InCNCmachining,whichofthefollowingG-codesisusedforrapidlinearpositioning?A.G00B.G01C.G02D.G034.The______isamechanicalcomponentusedtoreducefrictionbetweenrotatingshaftsandstationarysupportmembers,andtomaintainthepositionoftheshaftaccurately.A.couplingB.bearingC.sealD.bracket5.Inthefiniteelementanalysisofmechanicalstructures,theoriginalcontinuousdesignareaisdividedintoanumberofsmalldiscreteunitsconnectedbynodes,thisprocessiscalled______.A.meshingB.post-processingC.loadingD.constraintsetting6.Formassproductionofhollowcylindricalpartswithhighdimensionalaccuracy,______isthemostsuitableformingprocess.A.hotforgingB.extrusionC.castingD.stamping7.The______obtainedafterroughmachiningneedstoberetainedforfinishingallowancebeforethefinalassemblyofparts.A.processallowanceB.assemblyclearanceC.nominaldimensionD.basicdeviation8.Inhydraulictransmissionsystems,______isthecomponentthatconvertshydraulicpressureenergyintomechanicalrotationalenergytooutputtorqueandspeed.A.hydraulicpumpB.hydrauliccylinderC.hydraulicmotorD.pressurevalve9.______isaheattreatmentprocessthatcanimprovethetoughnessofsteelparts,reduceinternalstress,andobtainacomprehensivecombinationofstrengthandtoughness.A.QuenchingB.TemperingC.NormalizingD.Annealing10.Whentwomechanicalpartsareassembledwithaninterferencefit,the______betweenthecontactsurfaceswillconnectthetwopartsfirmlywithoutadditionalfastenersinmanycases.A.frictionforceB.centrifugalforceC.inertialforceD.tangentialforce11.Inprecisionmachining,the______errorreferstotheerrorcausedbytheinconsistentwearofthetoolduringthelong-termprocessingofmultipleparts.A.positioningB.clampingC.toolwearD.thermaldeformation12.A______cammechanismhasacamwithacurvedcontourrotatingaroundafixedaxis,anddrivesthefollowertoachievereciprocatinglinearmotion.A.rotaryB.stationaryC.cylindricalD.conical13.Themodalanalysisofmechanicalstructuresismainlyusedtoobtainthe______andvibrationmodeofthestructureunderfreevibration.A.naturalfrequencyB.workingstressC.deformationD.loaddistribution14.Inordertopreventtheleakageoflubricatingoilinthegearboxandtheentryofexternaldustintothebox,______areinstalledatthepositionwheretheshaftextendsoutoftheboxbody.A.bearingsB.couplingsC.sealsD.gaskets15.Whichofthefollowingweldingmethodsbelongstofusionwelding?A.ResistanceweldingB.ArcweldingC.BrazingD.Frictionstirwelding16.ThenominalscrewsizeM16×1.5indicatesthatthe______ofthethreadis16mm,andthepitchis1.5mm.A.minordiameterB.pitchdiameterC.majordiameterD.rootdiameter17.______isarapidprototypingtechnologythatbuildssolidpartslayerbylayerbasedondigitalmodeldata,andisalsocalledadditivemanufacturing.A.3DprintingB.CNCmillingC.ForgingD.Casting18.Inthedesignofmechanicalproducts,______referstotheabilityofaproducttocompletethespecifiedfunctionwithinthespecifiedtimeandunderthespecifiedworkingconditions.A.reliabilityB.strengthC.stiffnessD.durability19.Whenmeasuringthesurfaceroughnessofamachinedpartwithaprofilometer,Rareferstothe______.A.maximumheightoftheprofileB.arithmeticmeandeviationoftheprofileC.ten-pointheightofthemicro-profileD.rootmeansquaredeviationoftheprofile20.Forafour-strokeinternalcombustionengine,theconnectingrodisusedtoconnectthepistonandthecrankshaft,andconvertthereciprocatinglinearmotionofthepistonintothe______ofthecrankshaft.A.oscillatingmotionB.reciprocatingmotionC.rotationalmotionD.planarmotionII.ReadingComprehension(Thereare2passagesinthispart.Eachpassageisfollowedbysomequestionsorunfinishedstatements.ForeachofthemtherearefourchoicesmarkedA,B,CandD.Choosethebestanswer.4pointsforeachquestion,40pointsintotal)Passage1Collaborativerobots,oftenshortenedtocobots,areanewgenerationofindustrialrobotsdesignedtoworksafelyalongsidehumanworkersinsharedworkspaces,unliketraditionalindustrialrobotsthatareusuallycagedofftopreventinjurytopersonnel.Intheautomotivecomponentassemblyline,cobotshavebeenwidelyadoptedforrepetitive,high-precisiontaskssuchasinsertingbearingsintogearhousings,tighteningfastenerswithcontrolledtorque,andsortingsmallprecisionparts.Oneofthecoreadvantagesofcobotsovertraditionalrobotsistheireasyprogramming:insteadofrequiringprofessionalengineerstowritecomplexcode,mostcobotscanbeprogrammedthroughhand-guidance,whereworkersdirectlymovetherobotarmtothedesiredpositionsandsavethepath.ArecentsurveyconductedbytheInternationalFederationofRobotics(IFR)showsthattheglobalinstallationvolumeofcobotsinsmallandmedium-sizedmechanicalmanufacturingenterprisesincreasedby42%year-on-yearin2025,mainlydrivenbythedemandforflexibleproduction.Unlikelarge-scaleautomatedproductionlinesthatareonlysuitableformassproductionofasingleproduct,cobot-basedworkstationscanbequicklyreconfiguredfordifferentproductiontasks,whichperfectlymatchesthecurrentmarkettrendofsmall-batchcustomizedmechanicalproducts.However,cobotsalsohavelimitations:theirpayloadisgenerallylowerthan10kgformostentry-levelmodels,andtheirrepeatpositioningaccuracyisslightlylowerthanthatofhigh-endtraditionalindustrialrobots,sotheyarenotsuitableforheavy-loadcuttingprocessingtasksthatrequireultra-highprecision.Questions1to5arebasedonPassage1:1.Whatisthemaindifferencebetweencobotsandtraditionalindustrialrobots?A.CobotshavehigherpayloadthantraditionalrobotsB.CobotscanworksafelywithhumanworkerswithoutisolationC.CobotshavehigherpositioningaccuracythantraditionalrobotsD.Cobotscanonlybeusedformassproduction2.WhichofthefollowingtasksisNOTmentionedasacommonapplicationofcobotsinautomotiveassembly?A.InsertingbearingsintogearhousingsB.TighteningfastenerswithconstanttorqueC.CuttingheavymechanicalpartsD.Sortingsmallprecisionparts3.WhatdoestheIFRsurveyindicateaboutcobotdevelopmentin2025?A.TheglobalcobotinstallationinSMEsgrewby42%comparedto2024B.Cobotshavereplacedmorethan40%ofhumanworkersinmechanicalmanufacturingC.Thepriceofcobotsdroppedby42%year-on-year,promotingtheirapplicationD.Mostlargeautomobileenterpriseshavestoppedpurchasingtraditionalindustrialrobots4.Whycancobotsadapttothetrendofcustomizedsmall-batchproduction?A.TheirprogrammingandworkstationreconfigurationcanbecompletedquicklyB.TheyhavelowerpurchasecostthantraditionalautomatedproductionlinesC.TheycancompletemultipleprocessingtasksatthesametimewithhigherspeedD.Theydonotrequireanymaintenanceduringlong-termoperation5.Whatcanbeinferredfromthepassageabouttheapplicationscopeofcobots?A.CobotswillcompletelyreplacetraditionalindustrialrobotsinthenextfiveyearsB.Cobotsaremoresuitableforsmallandmedium-sizedflexibleproductionscenariosC.CobotscanalreadymeettherequirementsofallmechanicalprocessingtasksD.Entry-levelcobotsaremostsuitableforheavy-loadultra-precisionprocessingtasksPassage2LaserPowderBedFusion(LPBF),oneofthemostmaturemetaladditivemanufacturingtechnologies,hasbeenwidelyusedinthemanufacturingofhigh-performancecomplexstructuralpartsintheaerospaceandaviationmachineryindustries.Differentfromtraditionalsubtractivemanufacturingmethodssuchasmillingandforging,LPBFmanufacturespartslayerbylayerbymeltingmetalpowderwithafocusedhigh-powerlaserbeam.Thismanufacturingmethodallowsdesignerstorealizecomplexinternalstructuressuchaslatticecoolingchannelsthatcannotbeproducedbytraditionalprocesses,whichgreatlyimprovesthedesignfreedomofmechanicalparts.Foraero-engineturbineblades,researchershaveusedLPBFtechnologytomanufacturebladeswithaninternalgradedlatticestructure,whichreducestheoverallweightofthebladeby18%whilemeetingtherequirementofhigh-temperaturestrength.Atthesametime,additivemanufacturingalsoshortensthedevelopmentcycleofnewaerospacepartsfromthetraditional6-12monthsto2-4weeks,whichgreatlyacceleratestheresearchanddevelopmentprogressofnewmodels.However,LPBFtechnologystillfacesseveralkeychallengesthatlimititslarge-scaleapplication.First,thesurfaceroughnessofLPBF-formedpartsisgenerallyhigherthanthatofpartsprocessedbytraditionalmilling,sopost-processingsuchasgrindingandpolishingisrequiredtomeettheassemblyaccuracyrequirements.Second,thethermalcyclingprocessduringmeltingandsolidificationwilleasilyleadtoresidualstressinsidetheparts,whichmaycausepartdeformationorcrackingafterlong-termuse.Inrecentyears,researchershaveproposedavarietyofin-situresidualstressmonitoringandcontrolmethodsbasedoninfraredthermalimagingandmachinelearning,whichhaveeffectivelyreducedtheresidualstresslevelofformedparts,bringingLPBFtechnologyclosertolarge-scaleindustrialapplication.Questions6to10arebasedonPassage2:1.WhatisthecoreworkingprincipleofLPBFadditivemanufacturing?A.RemovingexcessmaterialfromablanktogetthedesiredpartB.MeltingmetalpowderlayerbylayerwithalasertoformthepartC.ForgingablankunderhightemperatureandpressuretoshapethepartD.CuttingthepartbyaCNCmillingmachinelayerbylayer2.WhatadvantagedoesLPBFhaveovertraditionalmanufacturingprocessesforaerospaceparts?A.ItcanproducecomplexinternalstructuresthattraditionalprocessescannotachieveB.IthaslowerproductioncostformassproductionofstandardpartsC.ItcanproducepartswithzeroresidualstressandnodeformationD.Itcangetlowersurfaceroughnessthantraditionalmillingdirectly3.WhatbenefitdoesLPBFbringtothedevelopmentofnewaero-engineparts?A.Itimprovesthesurfaceroughnessofturbinebladeswithoutpost-processingB.ItincreasestheweightofthebladewhileimprovingitsstrengthC.ItshortensthedevelopmentcycleofnewpartsfrommonthstoweeksD.Iteliminatestherequirementofhigh-temperaturestrengthforturbineblades4.WhichofthefollowingisamajorchallengeofLPBFtechnologyatpresent?A.LPBFcannotbeusedtomanufacturemetalpartsB.ResidualstressgeneratedduringtheformingprocessmaycausepartfailureC.LPBFrequiresmuchlongerproductiontimethantraditionalforgingD.ThedesignfreedomofpartsmanufacturedbyLPBFisverylimited5.Accordingtothepassage,whatisthecurrentdevelopmenttrendofLPBFtechnology?A.ResearchersaredevelopingnewmethodstosolvethekeyproblemssuchasresidualstressB.LPBFhascompletelyreplacedtraditionalforgingtechnologyinaerospacemanufacturingC.LPBFismainlyusedfortheproductionoflow-precisioncivilianmachinerypartsD.TheapplicationscopeofLPBFisshrinkingduetoitsinherentdefectsIII.English-ChineseTranslation(TranslatethefollowingtwoparagraphsofmechanicalprofessionaltextintoChinese,putyourtranslationontheanswersheet.25pointsintotal)1.Thisseriesofhelicalgearreducersarespeciallydesignedforconveyorsystemsinminingmachinery.Theinputshaftisconnectedwiththemotorthroughanelasticcoupling,andtheoutputshafttransmitstorquetothedrivendrumthroughasplineconnection.Beforestartingthereducer,checkwhethertheoillevelofthegearoilintheoiltankreachesthemarkedline,andconfirmthatthereisnoabnormaljammingwhenrotatingtheinputshaftmanually.Duringoperation,ifthetemperatureofthereducerhousingexceeds80℃orabnormalnoiseoccurs,stopthemachineimmediatelyforinspection.2.Topologyoptimizationisastructuraloptimizationmethodcommonlyusedinmodernmechanicaldesign.Itobtainstheoptimalmaterialdistributionschemeinagivendesignareabyiterativelycalculatingthestressdistributionundergivenload,constraintandperformancerequirements,soastoachievethedesigngoalofmaximizingstructuralstiffnessorminimizingweightunderthepremiseofmeetingstrengthrequirements.Comparedwiththetraditionalexperience-baseddesignmethod,topologyoptimizationcansignificantlyreducetheweightofstructuralpartswhileensuringmechanicalperformance,andiswidelyusedinthedesignofautomobilebodystructures,aerospacesupportpartsandotherload-bearingcomponents.IV.TechnicalWriting(WriteabriefEnglishintroductiontotheroughturningprocessofa45#steelsteppedshaftforamechanicalpartsprocessingmanual.Yourwritingshouldcoverthebasicprocessingobject,processingtools,mainprocessingstepsandaccuracyrequirements,andthewordcountshouldbecontrolledbetween100-120words.15pointsintotal)I.VocabularyandStructure1.Answer:BExplanation:Inmechanicaldimensioning,toleranceisdefinedasthetotalpermissiblevariationofasizefromthenominaldimension,whichmatchesthedescriptioninthequestion.Allowancereferstotheintentionaldifferencebetweenthematingsizesoftwopartsforfit,deviationreferstothedifferencebetweenasingleactualsizeandthenominalsize,clearancereferstothegapbetweentwomatingpartsinaclearancefit.Therefore,Biscorrect.Explanation:Inmechanicaldimensioning,toleranceisdefinedasthetotalpermissiblevariationofasizefromthenominaldimension,whichmatchesthedescriptioninthequestion.Allowancereferstotheintentionaldifferencebetweenthematingsizesoftwopartsforfit,deviationreferstothedifferencebetweenasingleactualsizeandthenominalsize,clearancereferstothegapbetweentwomatingpartsinaclearancefit.Therefore,Biscorrect.2.Answer:CExplanation:Bevelgearsarespecificallydesignedtotransmitmotionandpowerbetweentwointersectingshafts.Spurgearsandhelicalgearsareusedforparallelshafttransmission,whilewormgearpairsareusedforstaggeredshafttransmissionwithlargespeedreductionratios.Therefore,Ciscorrect.3.Answer:AExplanation:IntheISOstandardG-codesystemforCNCmachining,G00isthecommandforrapidlinearpositioningwithoutcutting.G01islinearinterpolationcutting,G02isclockwisecircularinterpolation,andG03iscounter-clockwisecircularinterpolation.Therefore,Aiscorrect.4.Answer:BExplanation:Abearingisakeymechanicalcomponentthatsupportstherotatingshaft,reducesfrictionbetweentheshaftandthesupport,andmaintainstheshaft'srotationalpositionaccuracy.Couplingisusedtoconnecttwoshaftstotransmittorque,sealisusedtopreventfluidleakage,bracketisusedtosupportcomponents.Therefore,Biscorrect.5.Answer:AExplanation:Meshingisthecorepreprocessingstepinfiniteelementanalysis,whichdividesthecontinuousdesigndomainintodiscretesmallunitsconnectedbynodes.Post-processingisthestepofextractinganalysisresultsaftercalculation,loadingreferstoapplyingexternalloadstothemodel,constraintsettingisfixingthedegreesoffreedomofthemodel.Therefore,Aiscorrect.6.Answer:BExplanation:Extrusionisaformingprocessthatforcesmetalmaterialtoflowthroughadietoobtainthedesiredcross-sectionalshape,whichisverysuitableformassproductionofhollowcylindricalpartswithhighdimensionalaccuracy.Hotforgingissuitableforsolidforgings,castinghaslowaccuracyforsmallhollowparts,stampingismainlyusedforthinsheetparts.Therefore,Biscorrect.7.Answer:AExplanation:Processallowanceistheextramaterialretainedontheroughmachinedblankforthefinishingprocesstoensurethefinaldimensionandsurfacequalityofthepart.Assemblyclearanceisthegapbetweenmatingpartsduringassembly,nominaldimensionisthebasicdesigndimension,basicdeviationisthedeviationusedtodeterminethepositionofthetolerancezone.Therefore,Aiscorrect.8.Answer:CExplanation:Ahydraulicmotorconvertshydraulicpressureenergyintomechanicalrotationalenergy,outputtingtorqueandrotationalspeed.Ahydraulicpumpconvertsmechanicalenergyintohydraulicpressureenergy,ahydrauliccylinderoutputslinearmotion,apressurevalveisusedtoregulatethepressureofthehydraulicsystem.Therefore,Ciscorrect.9.Answer:BExplanation:Temperingisaheattreatmentprocessperformedafterquenching,whichcanreducetheinternalstressgeneratedduringquenching,improvethetoughnessofsteel,andobtainacomprehensivecombinationofstrengthandtoughness.Quenchingimprovesthehardnessandstrengthofsteel,normalizingrefinesthegrainstructureofcastings,annealingsoftenssteelforsubsequentprocessing.Therefore,Biscorrect.10.Answer:AExplanation:Ininterferencefit,thefrictionforcegeneratedbythepositivepressurebetweenthecontactsurfacesofthetwopartscanachieveafirmconnectionwithoutadditionalfastenersinmanyapplications.Centrifugalforceistheinertiaforcegeneratedbyrotatingobjects,inertialforceistheforcegeneratedbyaccelerationofmotion,tangentialforceistheforcetangenttothecontactsurface.Therefore,Aiscorrect.11.Answer:CExplanation:Toolwearerroristhemachiningerrorcausedbythegradualwearofthetoolduringlong-termcontinuousprocessingofmultipleparts.Positioningerrorcomesfrominaccuratepositioningoftheworkpiece,clampingerrorcomesfromclampingdeformation,thermaldeformationerrorcomesfromtemperatureriseofthemachinetoolorworkpiece.Therefore,Ciscorrect.12.Answer:AExplanation:Arotarycammechanismiscomposedofarotatingcamwithacurvedcontourandafollower,whichcandrivethefollowertodoreciprocatinglinearoroscillatingmotion.Astationarycamhasafixedcambody,andthefollowermovesalongthecamcontour,acylindricalcamisusedtodrivethefollowertomoveaxially.Therefore,Aiscorrect.13.Answer:AExplanation:Modalanalysisisacommondynamicanalysismethodformechanicalstructures,whichismainlyusedtoobtainthenaturalfrequencyandvibrationmodeofthestructure,providingabasisforvibrationresistancedesign.Workingstress,deformationandloaddistributionareobtainedfromstaticstructuralanalysis.Therefore,Aiscorrect.14.Answer:CExplanation:Sealsareinstalledatthegapbetweentheshaftandtheboxhousingtopreventtheleakageofinternallubricatingoilandtheentryofexternaldustandimpurities.Bearingssupporttheshaft,couplingsconnecttwoshafts,gasketsareusedforsealingbetweenflatjointsurfaces.Therefore,Ciscorrect.15.Answer:BExplanation:Arcweldingusestheheatgeneratedbytheelectricarctomeltthebasemetalandtheweldingwiretoformaweld,whichbelongstofusionwelding.Resistanceweldingandfrictionstirweldingbelongtosolidphasewelding,brazingusesafillermetalwithalowermeltingpointthanthebasemetaltojoinpartswithoutmeltingthebasemetal.Therefore,Biscorrect.16.Answer:CExplanation:Inthestandardmetricthreadmarkingmethod,Mfollowedbythenominalsizerepresentsthemajordiameterofthethread,andthevalueafter×isthepitch.Themajordiameteristhelargestdiameteroftheexternalthread,whichisthenominalsizeofthethread.Minordiameterandrootdiameterarethesmallestdiameterofthethread,pitchdiameteristhediameteroftheimaginarycylinderwherethethreadthicknessisequaltothegroovewidth.Therefore,Ciscorrect.17.Answer:AExplanation:3Dprintingisanothernameforadditivemanufacturing,whichisalayer-by-layermanufacturingtechnologybasedondigitalmodels.CNCmilling,forgingandcastingarealltraditionalmanufacturingprocesses,notadditivemanufacturing.Therefore,Aiscorrect.18.Answer:AExplanation:Reliabilityisdefinedastheabilityofamechanicalproducttocompletethespecifiedfunctionwithinthespecifiedtimeandunderspecifiedworkingconditions.Strengthistheabilitytoresistdamageunderload,stiffnessistheabilitytoresistdeformation,durabilityistheabilitytoresistwearandagingduringlong-termuse.Therefore,Aiscorrect.19.Answer:BExplanation:Rainsurfaceroughnessmeasurementreferstothearithmeticmeandeviationoftheprofile,whichisthemostcommonlyusedevaluationparameterforsurfaceroughness.Rzistheten-pointheightofthemicro-profile,Rmaxisthemaximumheightoftheprofile,Rqistherootmeansquaredeviation.Therefore,Biscorrect.20.Answer:CExplanation:Inafour-strokeinternalcombustionengine,thepistondoesreciprocatinglinearmotioninthecylinder,theconnectingrodtransferstheforceofthepistontothecrankshaft,andconvertsthereciprocatinglinearmotionintothecontinuousrotationalmotionofthecrankshafttooutputpower.Therefore,Ciscorrect.II.ReadingComprehensionPassage11.Answer:BExplanation:Accordingtothefirstparagraphofthepassage,"Collaborativerobots...unliketraditionalindustrialrobotsthatareusuallycagedofftopreventinjurytopersonnel",itcanbeseenthatthecoredifferenceisthatcobotscanworksafelywithhumanswithoutisolationcages.OptionAiswrongbecausethepassagementionsthatthepayloadofmostentry-levelcobotsislessthan10kg,whichislowerthantraditionalheavy-dutyindustrialrobots.OptionCiswrongbecausethepassagepointsoutthatthepositioningaccuracyofcobotsisslightlylowerthanthatofhigh-endtraditionalrobots.OptionDiswrongbecausethepassagementionsthatcobotsaremoresuitableforsmall-batchcustomizedproduction,notonlymassproduction.Therefore,Biscorrect.2.Answer:CExplanation:Thepassagementionstheapplicationscenariosofcobotsinautomotiveassembly:"insertingbearingsintogearhousings,tighteningfastenerswithcontrolledtorque,andsortingsmallprecisionparts",andfinallypointsoutthatcobots"arenotsuitableforheavy-loadcuttingprocessingtasksthatrequireultra-highprecision".Cuttingheavymechanicalpartsisnotacommonapplication,soCiscorrect.3.Answer:AExplanation:Theoriginaltextofthesurveyresultis"theglobalinstallationvolumeofcobotsinsmallandmedium-sizedmechanicalmanufacturingenterprisesincreasedby42%year-on-yearin2025",year-on-yeargrowthmeanscomparedwiththesameperiodofthepreviousyear(2024),soAiscorrect.Theotheroptionsarenotmentionedinthepassage:Bsays40%ofhumanworkersarereplaced,Csayspricedropsby42%,Dsayslargeenterprisesstopbuyingtraditionalrobots,allarewrong.4.Answer:AExplanation:Thepassagepointsoutthat"cobot-basedworkstationscanbequicklyreconfiguredfordifferentproductiontasks",combinedwiththepreviousdescriptionthatcobotprogrammingcanbecompletedquicklythroughhand-guidance,itcanbeseenthatthereasonwhycobotsadapttosmall-batchcustomizedproductionisthattheirreconfigurationandprogrammingarefast.Theotheroptionsarenotmentionedinthepassage:Bdoesnotmentionthepurchasecost,Cdoesnotmentionhigherspeedformulti-tasking,Ddoesnotmentionnomaintenance.Therefore,Aiscorrect.5.Answer:BExplanation:Accordingtothepassage,thegrowthofcobotinstallationisthefastestinsmallandmedium-sizedmanufacturingenterprises,andcobotsaresuitableforflexibleproductionofsmall-batchcustomizedproducts,soitcanbeinferredthatcobotsaremoresuitableforsmallandmedium-sizedflexibleproductionscenarios.OptionAiswrongbecausethereisnomentionthatcobotswillcompletelyreplacetraditionalrobots,OptionCiswrongbecausecobotshaveobviouslimitationsandcannotadapttoalltasks,OptionDiswrongbecauseentry-levelcobotsarenotsuitableforheavy-loadultra-precisiontasks.Therefore,Biscorrect.Passage21.Answer:BExplanation:TheoriginaldescriptionofLPBF'sworkingprincipleis"LPBFmanufacturespartslayerbylayerbymeltingmetalpowderwithafocusedhigh-powerlaserbeam",whichmatchesoptionB.OptionAistheprincipleoftraditionalsubtractivemanufacturing,OptionCistheprincipleofforging,OptionDistheprincipleofCNCmilling,allarewrong.Therefore,Biscorrect.2.Answer:AExplanation:ThepassagepointsoutthatLPBF"allowsdesignerstorealizecomplexinternalstructuressuchaslatticecoolingchannelsthatcannotbeproducedbytraditionalprocesses",whichisthecoreadvantageofLPBFforaerospaceparts.OptionBiswrongbecausethepassagedoesnotmentionthatLPBFhaslowercostformassproductionofstandardparts,OptionCiswrongbecauseresidualstressisoneofthemainchallengesofL