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(Ⅰ) 求常数a,b及ξ1所对应的特征值; (Ⅱ) 矩阵A可否相似对角化若A可对角化,对A进行相似对角化;若A不可对角化,说明理由。
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设3阶实对称矩阵A的秩为2λ1=λ2=6是A的二重特征值.若α1=1a0α2=211α3=01-1T
已知矩阵M.=其中a∈R若点P1-2在矩阵M.的变换下得到点P′-40求实数a的值并求矩阵M.的特征
已知矩阵M.=其中a∈R若点P1-2在矩阵M.的变换下得到点P′-40.1求实数a的值2求矩阵M.的
设λ1λ2是n阶实对称矩阵A的两个不同的特征值α是A的对应于特征值λ1的一个单位特征向量则矩阵B=A
已知λ1=6λ2=λ3=3是实对称矩阵A的三个特征值.且对应于λ2=λ3=3的特征向量为α2=-10
若矩阵A.有特征值λ1=3λ2=-1它们所对应的特征向量分别为e1=和e2=求矩阵A.
已知矩阵A.=若点P11在矩阵A.对应的变换作用下得到点P′0-8.1求实数a的值2求矩阵A.的特征
n*n矩阵可看作是n维空间中的线性变换矩阵的特征向量经过线性变换后只是乘以某个常数特征值因此特征向
1/3
1
3
9
[*]Ⅰ求常数ab及ξ1所对应的特征值Ⅱ矩阵A可否相似对角化若A可对角化对A进行相似对角化若A不可对
设3阶矩阵A的特征值为11-2对应的特征向量依次为 1求矩阵A 2求A2009.
设A是3阶实对称矩阵已知A的每行元素之和为3且有二重特征值λ1=λ2=1.求A的全部特征值特征向量并
设二次型 其中二次型的矩阵A的特征值之和为1特征值之积为-12. 1求ab的值 2利用正交变换将
已知λ1=6λ2=λ3=3是实对称矩阵A的三个特征值且对应于λ2=λ3=3的特征向量为α2=-101
二阶矩阵M.有特征值其对应的一个特征向量e=并且矩阵M.对应的变换将点变换成点.Ⅰ求矩阵M.Ⅱ求矩阵
设3阶实对称矩阵A的秩为2λ1=λ2=6是A的二重特征值.若α1=1a0Tα2=211Tα3=01-
n*n矩阵可看作是n维空间中的线性变换矩阵的特征向量经过线性变换后只是乘以某个常数特征值因此特征向
1/3
1
3
9
设3阶实对称矩阵A的特征值是123矩阵A的属于特征值12的特征向量分别是α1=-1-11Tα2=1-
设三阶矩阵A的特征值为λ1=-1λ2=0λ3=1则下列结论不正确的是______.
矩阵A不可逆
矩阵A的秩为零
特征值-1,1对应的特征值向量正交
方程组AX=0的基础解系含有一个线性无关的解向量
设3阶实对称矩阵A的秩为2λ1=λ2=6是A的二重特征值.若α1=1a0Tα2=211Tα3=01-
设3阶实对称矩阵A的特征值λ1=8λ2=λ3=2矩阵A属于特征值λ1=8的特征向量为α1=1k1T属
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请阅读下面材料 __在十六大__要尊重和保护一切有益于人民和社会的劳动不论是体力劳动还是脑力劳动不论是简单劳动还是复杂劳动一切为我国社会主义现代化建设做出贡献的劳动都是光荣的都应谊得到承认和尊重要确立劳动资本技术和管理等生产要素按贡献参与分配的原则完善按劳分配为主体多种分配方式并存的分配制度 运用马克思主义政治经济学中关于价值创造和价值分配的理论分析我国现行阶段的分配制度
Directions:Readthefollowingtext.Choosethebestwordsfor eachnumberedblankandmarkABCorDonANSWERSHEET1. Mostplantscanmaketheirownfood fromsunlight1somehavediscoveredthatstealingisan easierwaytoliveThousandsofplantspeciesgetby2 photosynthesizingandover400ofthesespeciesseemtoliveby pilferingsugarsfromanunderground3offungi真菌.But in4ahandfuloftheseplantshasthismodusoperandibeen tracedtoarelativelyobscurefungus.Tofindouthow5 are6mycologistMartinBidartondoofthe UniversityofCaliforniaatBerkeleyandhisteamlookedintheirroots.What theyfoundwere7ofacommontypeoffungusso 8thatitisfoundinnearly70percentofallplants.The presenceofthiscommonfungusintheseplantsnotonly9 athowtheysurvivesaysBidartondobutalsosuggeststhat manyordinaryplantsmightprosperfromalittlelootingtoo. Plantshave10relationstogetwhattheyneedto survive.Normal11plantscanmaketheirowncarbohydrates throughphotosynthesisbuttheystillneedminerals.Mostplantshave 12asymbioticrelationshipwitha13 networkofwhatarecalledmycorrhizalfungiwhichliesbeneaththe forest14.Thefungihelpgreenplantsabsorbminerals throughtheirrootsand15theplantsnormally 16thefungiwithsugarsorcarbon.Withanumberofplants sharingthesamefungalwebitwasperhaps17thatafew cheaters—dubbedepiparasites—wouldevolvetobeatthesystem.18 theseplantsreversedtheflowofcarbon19it intotheirrootsfromthefungi20releasingitas payment.
决定一定时期内流通中所需货币量的因素主要有
Directions:Readthefollowingtext.Choosethebestwordsfor eachnumberedblankandmarkABCorDonANSWERSHEET1. Mostplantscanmaketheirownfood fromsunlight1somehavediscoveredthatstealingisan easierwaytoliveThousandsofplantspeciesgetby2 photosynthesizingandover400ofthesespeciesseemtoliveby pilferingsugarsfromanunderground3offungi真菌.But in4ahandfuloftheseplantshasthismodusoperandibeen tracedtoarelativelyobscurefungus.Tofindouthow5 are6mycologistMartinBidartondoofthe UniversityofCaliforniaatBerkeleyandhisteamlookedintheirroots.What theyfoundwere7ofacommontypeoffungusso 8thatitisfoundinnearly70percentofallplants.The presenceofthiscommonfungusintheseplantsnotonly9 athowtheysurvivesaysBidartondobutalsosuggeststhat manyordinaryplantsmightprosperfromalittlelootingtoo. Plantshave10relationstogetwhattheyneedto survive.Normal11plantscanmaketheirowncarbohydrates throughphotosynthesisbuttheystillneedminerals.Mostplantshave 12asymbioticrelationshipwitha13 networkofwhatarecalledmycorrhizalfungiwhichliesbeneaththe forest14.Thefungihelpgreenplantsabsorbminerals throughtheirrootsand15theplantsnormally 16thefungiwithsugarsorcarbon.Withanumberofplants sharingthesamefungalwebitwasperhaps17thatafew cheaters—dubbedepiparasites—wouldevolvetobeatthesystem.18 theseplantsreversedtheflowofcarbon19it intotheirrootsfromthefungi20releasingitas payment.
商品流通公式与资本流通公式的区别在于
Directions:Readthefollowingtext.Choosethebestwordsfor eachnumberedblankandmarkABCorDonANSWERSHEET1. Mostplantscanmaketheirownfood fromsunlight1somehavediscoveredthatstealingisan easierwaytoliveThousandsofplantspeciesgetby2 photosynthesizingandover400ofthesespeciesseemtoliveby pilferingsugarsfromanunderground3offungi真菌.But in4ahandfuloftheseplantshasthismodusoperandibeen tracedtoarelativelyobscurefungus.Tofindouthow5 are6mycologistMartinBidartondoofthe UniversityofCaliforniaatBerkeleyandhisteamlookedintheirroots.What theyfoundwere7ofacommontypeoffungusso 8thatitisfoundinnearly70percentofallplants.The presenceofthiscommonfungusintheseplantsnotonly9 athowtheysurvivesaysBidartondobutalsosuggeststhat manyordinaryplantsmightprosperfromalittlelootingtoo. Plantshave10relationstogetwhattheyneedto survive.Normal11plantscanmaketheirowncarbohydrates throughphotosynthesisbuttheystillneedminerals.Mostplantshave 12asymbioticrelationshipwitha13 networkofwhatarecalledmycorrhizalfungiwhichliesbeneaththe forest14.Thefungihelpgreenplantsabsorbminerals throughtheirrootsand15theplantsnormally 16thefungiwithsugarsorcarbon.Withanumberofplants sharingthesamefungalwebitwasperhaps17thatafew cheaters—dubbedepiparasites—wouldevolvetobeatthesystem.18 theseplantsreversedtheflowofcarbon19it intotheirrootsfromthefungi20releasingitas payment.
Directions:Readthefollowingtext.Choosethebestwordsfor eachnumberedblankandmarkABCorDonANSWERSHEET1. Mostplantscanmaketheirownfood fromsunlight1somehavediscoveredthatstealingisan easierwaytoliveThousandsofplantspeciesgetby2 photosynthesizingandover400ofthesespeciesseemtoliveby pilferingsugarsfromanunderground3offungi真菌.But in4ahandfuloftheseplantshasthismodusoperandibeen tracedtoarelativelyobscurefungus.Tofindouthow5 are6mycologistMartinBidartondoofthe UniversityofCaliforniaatBerkeleyandhisteamlookedintheirroots.What theyfoundwere7ofacommontypeoffungusso 8thatitisfoundinnearly70percentofallplants.The presenceofthiscommonfungusintheseplantsnotonly9 athowtheysurvivesaysBidartondobutalsosuggeststhat manyordinaryplantsmightprosperfromalittlelootingtoo. Plantshave10relationstogetwhattheyneedto survive.Normal11plantscanmaketheirowncarbohydrates throughphotosynthesisbuttheystillneedminerals.Mostplantshave 12asymbioticrelationshipwitha13 networkofwhatarecalledmycorrhizalfungiwhichliesbeneaththe forest14.Thefungihelpgreenplantsabsorbminerals throughtheirrootsand15theplantsnormally 16thefungiwithsugarsorcarbon.Withanumberofplants sharingthesamefungalwebitwasperhaps17thatafew cheaters—dubbedepiparasites—wouldevolvetobeatthesystem.18 theseplantsreversedtheflowofcarbon19it intotheirrootsfromthefungi20releasingitas payment.
社会资本扩大再生产的前提条件是
Directions:Readthefollowingtext.Choosethebestwordsfor eachnumberedblankandmarkABCorDonANSWERSHEET1. Mostplantscanmaketheirownfood fromsunlight1somehavediscoveredthatstealingisan easierwaytoliveThousandsofplantspeciesgetby2 photosynthesizingandover400ofthesespeciesseemtoliveby pilferingsugarsfromanunderground3offungi真菌.But in4ahandfuloftheseplantshasthismodusoperandibeen tracedtoarelativelyobscurefungus.Tofindouthow5 are6mycologistMartinBidartondoofthe UniversityofCaliforniaatBerkeleyandhisteamlookedintheirroots.What theyfoundwere7ofacommontypeoffungusso 8thatitisfoundinnearly70percentofallplants.The presenceofthiscommonfungusintheseplantsnotonly9 athowtheysurvivesaysBidartondobutalsosuggeststhat manyordinaryplantsmightprosperfromalittlelootingtoo. Plantshave10relationstogetwhattheyneedto survive.Normal11plantscanmaketheirowncarbohydrates throughphotosynthesisbuttheystillneedminerals.Mostplantshave 12asymbioticrelationshipwitha13 networkofwhatarecalledmycorrhizalfungiwhichliesbeneaththe forest14.Thefungihelpgreenplantsabsorbminerals throughtheirrootsand15theplantsnormally 16thefungiwithsugarsorcarbon.Withanumberofplants sharingthesamefungalwebitwasperhaps17thatafew cheaters—dubbedepiparasites—wouldevolvetobeatthesystem.18 theseplantsreversedtheflowofcarbon19it intotheirrootsfromthefungi20releasingitas payment.
PartADirections:Readthefollowingfourtexts.Answer thequestionsbeloweachtextbychoosingABCorD.Markyouranswerson ANSWERSHEET1.Text1 Afactorythatmakesuraniumfuelfor nuclearreactorshadaspillsobaditkepttheplantclosedforsevenmonths lastyearandbecameoneofonlythreeeventsinallof2006seriousenoughfor theNuclearRegulatoryCommissiontoincludeinanannualreporttoCongress. Afteraninvestigationthecommissionchangedthetermsofthefactory’s licenseandsaidthepublichad20daystorequestahearingonthe changes.Butnomemberofthepubliceverdid.Infactno memberofthepubliccouldfindoutaboutthechanges.Thedocumentdescribing themincludingthenoticeofhearingrightsforanyonewhofeltadversely affectedwasstampedofficialuseonlymeaningthatitwasnotpublicly accessible.TheagencywouldnotevenhavetoldCongresswhich factorywasinvolvedwereitnotfortheeffortsofGregoryB.Jaczkooneof thefivecommissioners.Mr.JaczkoidentifiedthecompanyNuclearFuelServices ofErwinTenninamemorandumthatbecamepartofthepublicrecord.His memorandumsaidotherpublicdocumentswouldallowaninformedpersontodeduce thatthefactorybelongedtoNuclearFuelServices.Suchsecrecy bytheNuclearRegulatoryCommissionisnowcomingunderattackbyinfluential membersofCongress.Theselawmakersarguethattheagencyiswithholding numerousdocumentsaboutnuclearfacilitiesinthenameofnationalsecurity butthatmanywithhelddocumentsarenotsensitive.Thelawmakerssaytheagency mustrebalanceitspenchantforsecrecywiththepublic’srighttoparticipate inthelicensingprocessanditsrighttoknowaboutpotentialhazards.The agencythecongressmensaidhasremovedhundredsofinnocuousdocuments relatingtotheN.F.S.plantfrompublicview.Witha resurgenceofnuclearplantconstructionexpectedaftera30-yearhiatusagency officialssayfrequentlythattheyaretryingtostrikeabalancebetween winningpublicconfidencebyregulatingopenlyandprotectingsensitive information.AcommissionspokesmanScottBurnellsaidtheofficialuseonly designationwasunderreview.Aslaidoutbythecommission’s reporttoCongressandothersourcestheeventattheNuclearFuelService factorywasdiscoveredwhenasupervisorsawayellowliquiddribblingundera doorandintoahallway.Workershadpreviouslydescribedayellowliquidina gloveboxasealedcontainerwithglovesbuiltintothesidestoallowa techniciantomanipulateobjectsinsidebutmanagershaddecideditwas ordinaryuranium.Infactitwashighlyenricheduraniumthathadbeen declaredsurplusfromtheweaponsinventoryoftheEnergyDepartmentand senttotheplanttobedilutedtoastrengthappropriateforacivilian reactor.Ifthematerialhadgonecriticalitislikelythatatleastone workerwouldhavereceivedanexposurehighenoughtocauseacutehealtheffects ordeaththecommissionsaid.GenerallytheNuclear RegulatoryCommissiondoesdescribenuclearincidentsandchangesinlicenses. Butin2004accordingtothecommittee’slettertheOfficeofNavalReactors partoftheEnergyDepartmentreachedanagreementwiththecommissionthatany correspondencewithNuclearFuelServiceswouldbemarkedofficialuse only.Thewordinnocuouslastsentenceparagraph4isclosestinmeaningto
现代产权制度的特征主要有
价值转化成生产价格后价值价格和生产价格的关系是
Directions:Readthefollowingtext.Choosethebestwordsfor eachnumberedblankandmarkABCorDonANSWERSHEET1. Mostplantscanmaketheirownfood fromsunlight1somehavediscoveredthatstealingisan easierwaytoliveThousandsofplantspeciesgetby2 photosynthesizingandover400ofthesespeciesseemtoliveby pilferingsugarsfromanunderground3offungi真菌.But in4ahandfuloftheseplantshasthismodusoperandibeen tracedtoarelativelyobscurefungus.Tofindouthow5 are6mycologistMartinBidartondoofthe UniversityofCaliforniaatBerkeleyandhisteamlookedintheirroots.What theyfoundwere7ofacommontypeoffungusso 8thatitisfoundinnearly70percentofallplants.The presenceofthiscommonfungusintheseplantsnotonly9 athowtheysurvivesaysBidartondobutalsosuggeststhat manyordinaryplantsmightprosperfromalittlelootingtoo. Plantshave10relationstogetwhattheyneedto survive.Normal11plantscanmaketheirowncarbohydrates throughphotosynthesisbuttheystillneedminerals.Mostplantshave 12asymbioticrelationshipwitha13 networkofwhatarecalledmycorrhizalfungiwhichliesbeneaththe forest14.Thefungihelpgreenplantsabsorbminerals throughtheirrootsand15theplantsnormally 16thefungiwithsugarsorcarbon.Withanumberofplants sharingthesamefungalwebitwasperhaps17thatafew cheaters—dubbedepiparasites—wouldevolvetobeatthesystem.18 theseplantsreversedtheflowofcarbon19it intotheirrootsfromthefungi20releasingitas payment.
利润率的变动与
资本主义农场的劳动资料包括
Directions:Readthefollowingtext.Choosethebestwordsfor eachnumberedblankandmarkABCorDonANSWERSHEET1. Mostplantscanmaketheirownfood fromsunlight1somehavediscoveredthatstealingisan easierwaytoliveThousandsofplantspeciesgetby2 photosynthesizingandover400ofthesespeciesseemtoliveby pilferingsugarsfromanunderground3offungi真菌.But in4ahandfuloftheseplantshasthismodusoperandibeen tracedtoarelativelyobscurefungus.Tofindouthow5 are6mycologistMartinBidartondoofthe UniversityofCaliforniaatBerkeleyandhisteamlookedintheirroots.What theyfoundwere7ofacommontypeoffungusso 8thatitisfoundinnearly70percentofallplants.The presenceofthiscommonfungusintheseplantsnotonly9 athowtheysurvivesaysBidartondobutalsosuggeststhat manyordinaryplantsmightprosperfromalittlelootingtoo. Plantshave10relationstogetwhattheyneedto survive.Normal11plantscanmaketheirowncarbohydrates throughphotosynthesisbuttheystillneedminerals.Mostplantshave 12asymbioticrelationshipwitha13 networkofwhatarecalledmycorrhizalfungiwhichliesbeneaththe forest14.Thefungihelpgreenplantsabsorbminerals throughtheirrootsand15theplantsnormally 16thefungiwithsugarsorcarbon.Withanumberofplants sharingthesamefungalwebitwasperhaps17thatafew cheaters—dubbedepiparasites—wouldevolvetobeatthesystem.18 theseplantsreversedtheflowofcarbon19it intotheirrootsfromthefungi20releasingitas payment.
Directions:Readthefollowingtext.Choosethebestwordsfor eachnumberedblankandmarkABCorDonANSWERSHEET1. Mostplantscanmaketheirownfood fromsunlight1somehavediscoveredthatstealingisan easierwaytoliveThousandsofplantspeciesgetby2 photosynthesizingandover400ofthesespeciesseemtoliveby pilferingsugarsfromanunderground3offungi真菌.But in4ahandfuloftheseplantshasthismodusoperandibeen tracedtoarelativelyobscurefungus.Tofindouthow5 are6mycologistMartinBidartondoofthe UniversityofCaliforniaatBerkeleyandhisteamlookedintheirroots.What theyfoundwere7ofacommontypeoffungusso 8thatitisfoundinnearly70percentofallplants.The presenceofthiscommonfungusintheseplantsnotonly9 athowtheysurvivesaysBidartondobutalsosuggeststhat manyordinaryplantsmightprosperfromalittlelootingtoo. Plantshave10relationstogetwhattheyneedto survive.Normal11plantscanmaketheirowncarbohydrates throughphotosynthesisbuttheystillneedminerals.Mostplantshave 12asymbioticrelationshipwitha13 networkofwhatarecalledmycorrhizalfungiwhichliesbeneaththe forest14.Thefungihelpgreenplantsabsorbminerals throughtheirrootsand15theplantsnormally 16thefungiwithsugarsorcarbon.Withanumberofplants sharingthesamefungalwebitwasperhaps17thatafew cheaters—dubbedepiparasites—wouldevolvetobeatthesystem.18 theseplantsreversedtheflowofcarbon19it intotheirrootsfromthefungi20releasingitas payment.
PartADirections:Readthefollowingfourtexts.Answer thequestionsbeloweachtextbychoosingABCorD.Markyouranswerson ANSWERSHEET1.Text1 Afactorythatmakesuraniumfuelfor nuclearreactorshadaspillsobaditkepttheplantclosedforsevenmonths lastyearandbecameoneofonlythreeeventsinallof2006seriousenoughfor theNuclearRegulatoryCommissiontoincludeinanannualreporttoCongress. Afteraninvestigationthecommissionchangedthetermsofthefactory’s licenseandsaidthepublichad20daystorequestahearingonthe changes.Butnomemberofthepubliceverdid.Infactno memberofthepubliccouldfindoutaboutthechanges.Thedocumentdescribing themincludingthenoticeofhearingrightsforanyonewhofeltadversely affectedwasstampedofficialuseonlymeaningthatitwasnotpublicly accessible.TheagencywouldnotevenhavetoldCongresswhich factorywasinvolvedwereitnotfortheeffortsofGregoryB.Jaczkooneof thefivecommissioners.Mr.JaczkoidentifiedthecompanyNuclearFuelServices ofErwinTenninamemorandumthatbecamepartofthepublicrecord.His memorandumsaidotherpublicdocumentswouldallowaninformedpersontodeduce thatthefactorybelongedtoNuclearFuelServices.Suchsecrecy bytheNuclearRegulatoryCommissionisnowcomingunderattackbyinfluential membersofCongress.Theselawmakersarguethattheagencyiswithholding numerousdocumentsaboutnuclearfacilitiesinthenameofnationalsecurity butthatmanywithhelddocumentsarenotsensitive.Thelawmakerssaytheagency mustrebalanceitspenchantforsecrecywiththepublic’srighttoparticipate inthelicensingprocessanditsrighttoknowaboutpotentialhazards.The agencythecongressmensaidhasremovedhundredsofinnocuousdocuments relatingtotheN.F.S.plantfrompublicview.Witha resurgenceofnuclearplantconstructionexpectedaftera30-yearhiatusagency officialssayfrequentlythattheyaretryingtostrikeabalancebetween winningpublicconfidencebyregulatingopenlyandprotectingsensitive information.AcommissionspokesmanScottBurnellsaidtheofficialuseonly designationwasunderreview.Aslaidoutbythecommission’s reporttoCongressandothersourcestheeventattheNuclearFuelService factorywasdiscoveredwhenasupervisorsawayellowliquiddribblingundera doorandintoahallway.Workershadpreviouslydescribedayellowliquidina gloveboxasealedcontainerwithglovesbuiltintothesidestoallowa techniciantomanipulateobjectsinsidebutmanagershaddecideditwas ordinaryuranium.Infactitwashighlyenricheduraniumthathadbeen declaredsurplusfromtheweaponsinventoryoftheEnergyDepartmentand senttotheplanttobedilutedtoastrengthappropriateforacivilian reactor.Ifthematerialhadgonecriticalitislikelythatatleastone workerwouldhavereceivedanexposurehighenoughtocauseacutehealtheffects ordeaththecommissionsaid.GenerallytheNuclear RegulatoryCommissiondoesdescribenuclearincidentsandchangesinlicenses. Butin2004accordingtothecommittee’slettertheOfficeofNavalReactors partoftheEnergyDepartmentreachedanagreementwiththecommissionthatany correspondencewithNuclearFuelServiceswouldbemarkedofficialuse only.Itcanbeinferredfromthefirstthreeparagraphsthat
Text2 Thehistoryofmodempollutionproblems showsthatmosthaveresultedfromnegligenceandignorance.Wehavean appallingtendencytointerferewithnaturebeforeallofthepossible consequencesofouractionshavebeenstudiedindepth.Weproduceand distributeradioactivesubstancessyntheticchemicalsandmanyotherpotent compoundsbeforefullycomprehendingtheireffectsonlivingorganisms.Our educationisdangerouslyincomplete.Itwillbearguedthatthe purposeofscienceistomoveintounknownterritorytoexploreandto discover.Itcanbesaidthatsimilarriskshavebeentakenbeforeandthat theserisksarenecessarytotechnologicalprogress.These argumentsoverlookanimportantelement.Inthepastriskstakeninthenameof scientificprogresswererestrictedtoasmallplaceandbriefperiodoftime. Theeffectsoftheprocesseswenowstrivetomasterareneitherlocalizednor brief.Airpollutioncoversvasturbanareas.Oceanpollutantshavebeen discoveredinnearlyeverypartoftheworld.Syntheticchemicalsspreadover hugestretchesofforestandfarmlandmayremaininthesoilfordecadesand yearstocome.Radioactivepollutantswillbefoundinthebiospherefor generations.Thesizeandpersistenceoftheseproblemshavegrownwiththe expandingpowerofmodernscience.Onemightalsoarguethatthe hazardsofmodempollutantsaresmallcomparedwiththedangersassociatedwith otherhumanactivity.Noestimateoftheactualharmdonebysmogfalloutor chemicalresiduescanobscuretherealitythattherisksarebeingtakenbefore beingfullyunderstood.Theimportanceoftheseissuesliesin thefailureofsciencetopredictandcontrolhumaninterventionintonatural processes.Thetruemeasureofthedangerisrepresentedbythehazardswewill encounterifweenterthenewageoftechnologywithoutfirstevaluatingour responsibilitytoenvironment.Whichofthefollowingadjectivesmaybestdescribethetoneofthistext
Directions:Readthefollowingtext.Choosethebestwordsfor eachnumberedblankandmarkABCorDonANSWERSHEET1. Mostplantscanmaketheirownfood fromsunlight1somehavediscoveredthatstealingisan easierwaytoliveThousandsofplantspeciesgetby2 photosynthesizingandover400ofthesespeciesseemtoliveby pilferingsugarsfromanunderground3offungi真菌.But in4ahandfuloftheseplantshasthismodusoperandibeen tracedtoarelativelyobscurefungus.Tofindouthow5 are6mycologistMartinBidartondoofthe UniversityofCaliforniaatBerkeleyandhisteamlookedintheirroots.What theyfoundwere7ofacommontypeoffungusso 8thatitisfoundinnearly70percentofallplants.The presenceofthiscommonfungusintheseplantsnotonly9 athowtheysurvivesaysBidartondobutalsosuggeststhat manyordinaryplantsmightprosperfromalittlelootingtoo. Plantshave10relationstogetwhattheyneedto survive.Normal11plantscanmaketheirowncarbohydrates throughphotosynthesisbuttheystillneedminerals.Mostplantshave 12asymbioticrelationshipwitha13 networkofwhatarecalledmycorrhizalfungiwhichliesbeneaththe forest14.Thefungihelpgreenplantsabsorbminerals throughtheirrootsand15theplantsnormally 16thefungiwithsugarsorcarbon.Withanumberofplants sharingthesamefungalwebitwasperhaps17thatafew cheaters—dubbedepiparasites—wouldevolvetobeatthesystem.18 theseplantsreversedtheflowofcarbon19it intotheirrootsfromthefungi20releasingitas payment.
Directions:Readthefollowingtext.Choosethebestwordsfor eachnumberedblankandmarkABCorDonANSWERSHEET1. Mostplantscanmaketheirownfood fromsunlight1somehavediscoveredthatstealingisan easierwaytoliveThousandsofplantspeciesgetby2 photosynthesizingandover400ofthesespeciesseemtoliveby pilferingsugarsfromanunderground3offungi真菌.But in4ahandfuloftheseplantshasthismodusoperandibeen tracedtoarelativelyobscurefungus.Tofindouthow5 are6mycologistMartinBidartondoofthe UniversityofCaliforniaatBerkeleyandhisteamlookedintheirroots.What theyfoundwere7ofacommontypeoffungusso 8thatitisfoundinnearly70percentofallplants.The presenceofthiscommonfungusintheseplantsnotonly9 athowtheysurvivesaysBidartondobutalsosuggeststhat manyordinaryplantsmightprosperfromalittlelootingtoo. Plantshave10relationstogetwhattheyneedto survive.Normal11plantscanmaketheirowncarbohydrates throughphotosynthesisbuttheystillneedminerals.Mostplantshave 12asymbioticrelationshipwitha13 networkofwhatarecalledmycorrhizalfungiwhichliesbeneaththe forest14.Thefungihelpgreenplantsabsorbminerals throughtheirrootsand15theplantsnormally 16thefungiwithsugarsorcarbon.Withanumberofplants sharingthesamefungalwebitwasperhaps17thatafew cheaters—dubbedepiparasites—wouldevolvetobeatthesystem.18 theseplantsreversedtheflowofcarbon19it intotheirrootsfromthefungi20releasingitas payment.
垄断资本主义最根本的经济特征是
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