【单选题】 Chromosomes are regarded today as the major carriers of genetic material, （） of DNA and various types of protein.
A. consisting
B. as to consist
C. consist
D. which consisting
A. consisting
B. as to consist
C. consist
D. which consisting
【单选题】AlAskA BEComE thE Forty-ninth stAtE in 1959,AnD hAwAii BECAmE thE FiFtiEth stAtE lAtEly thAt yEAr.
【单选题】 Which of the following is NOT discussed as an ability animals are thought to have
A．( Selecting among choices
B．( Anticipating events to come
C．( Remembering past experiences
D．( Communicating emotions
A．( Selecting among choices
B．( Anticipating events to come
C．( Remembering past experiences
D．( Communicating emotions
【分析解答题】rEADing 1 "ExotiC AnDEnDAngErED spECiEs"
→ whEn you hEAr somEonE BuBBling EnthusiAstiCAlly ABout An ExotiC spECiEs, you CAn sAFEly BEt thE spEAkEr isn’t An ECologist. this is A nAmE For A rEsiDEnt oF An EstABlishED Community thAt wAs DEliBErAtEly or ACCiDEntAlly movED From its homE rAngE AnD BECAmE EstABlishED ElsEwhErE. unlikE most imports, whiCh CAn’t tAkE holD outsiDE thEir homE rAngE, An ExotiC spECiEs pErmAnEntly insinuAtEs itsElF into A nEw Community.
somEtimEs thE ADDitions ArE hArmlEss AnD EvEn hAvE BEnEFiCiAl EFFECts. morE oFtEn, thEy mAkE nAtivE spECiEs EnDAngErED spECiEs, whiCh By DEFinition ArE ExtrEmEly vulnErABlE to ExtinCtion. oF All spECiEs on thE rArE or EnDAngErED lists or thAt rECEntly BECAmE ExtinCt, ClosE to 70 pErCEnt owE thEir prECArious ExistEnCE or DEmisE to DisplACEmEnt By ExotiC spECiEs. two ExAmplEs ArE inCluDED hErE to illustrAtE thE proBlEm.
During thE 1800s,British sEttlErs inAustrAliA just CoulDn’t BonD with thE koAlAs AnD kAngAroos, so thEy stArtED to import FAmiliAr AnimAls From thEir homElAnD、in 1859, in whAt woulD BE thE stArt oF A wholEsAlE DisAstEr, A northErnAustrAliAn lAnDownEr importED AnD thEn rElEAsED two DozEn wilDEuropEAn rABBits (oryCtolAgus CuniCulus). gooD FooD AnD gooD sport hunting—thAt wAs thE iDEA、An iDEAl rABBit hABitAt with no nAturAl prEDAtors wAs thE rEAlity.
six yEArs lAtEr, thE lAnDownEr hAD killED 20,000 rABBits AnD wAs BEsiEgED By 20,000 morE. thE rABBits DisplACED livEstoCk, EvEn kAngAroos. nowAustrAliA hAs 200 to 300 million hippityhopping through thE southErn hAlF oF thE Country. thEy ovErgrAzE pErEnniAl grAssEs in gooD timEs AnD strip BArk From shruBs AnD trEEs During Droughts. you know whErE thEy’vE BEEn; thEy trAnsForm grAsslAnDs AnD shruBlAnDs into EroDED DEsErts. thEy hAvE BEEn shot AnD poisonED、thEir wArrEns hAvE BEEn plowED unDEr, FumigAtED, AnD DynAmitED、EvEn whEn All-out AssAults rEDuCED thEir populAtion sizE By 70 pErCEnt, thE rApiDly rEproDuCing imports mADE A ComEBACk in lEss thAn A yEAr.DiD thE ConstruCtion oF A 2,000-milE-long FEnCE protECt wEstErnAustrAliA no. rABBits mADE it to thE othEr siDE BEForE workErs FinishED thE FEnCE.
→ in 1951, govErnmEnt workErs introDuCED A myxomA virus By wAy oF milDly inFECtED southAmEriCAn rABBits, its normAl hosts. this virus CAusEs myxomAtosis. thE DisEAsE hAs milD EFFECts on southAmEriCAn rABBits thAt CoEvolvED with thE virus But nEArly AlwAys hAD lEthAl EFFECts on o. CuniCulus.Biting insECts, mAinly mosquitoEs AnD FlEAs, quiCkly trAnsmit thE virus From host to host. hAving no CoEvolvED DEFEnsEs AgAinst thE novEl virus, thEEuropEAn rABBits DiED in DrovEs.But, As you might ExpECt, nAturAl sElECtion hAs sinCE FAvorED rApiD growth oF populAtions oF o. CuniCulus rEsistAnt to thE virus.
→ in 1991, on An uninhABitED islAnD in spEnCEr gulF,AustrAliAn rEsEArChErs rElEAsED A populAtion oF rABBits thAt thEy hAD injECtED with A CAlCivirus. thE rABBits DiED quiCkly AnD rElAtivEly pAinlEssly From BlooD Clots in thEir lungs, hEArts, AnD kiDnEys. in 1995, thE tEst virus EsCApED From thE islAnD, possiBly on insECt vECtors. it hAs BEEn killing 80 to 95 pErCEnt oF thE ADult rABBits inAustrAliAn rEgions.At this writing, rEsEArChErs ArE now quEstioning whEthEr thE CAlCivirus shoulD BE usED on A wiDEsprEAD sCAlE, whEthEr it CAn jump BounDAriEs AnD inFECt AnimAls othEr thAn rABBits (suCh As humAns); AnD whAt thE long-tErm ConsEquEnCEs will BE.
A、vinE CAllED kuDzu (puErAriA loBAtA) wAs DEliBErAtEly importED From jApAn to thE unitED stAtEs, whErE it FACEs no sErious thrEAts From hErBivorEs, pAthogEns, or CompEtitor plAnts. in tEmpErAtE pArts oFAsiA, it is A wEll-BEhAvED lEgumE with A wEll-DEvElopED root systEm. it sEEmED likE A gooD iDEA to usE it to Control Erosion on hills AnD highwAy EmBAnkmEnts in thE southEAstErn unitED stAtEs.
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with nothing to stop it, though, ku
→ whEn you hEAr somEonE BuBBling EnthusiAstiCAlly ABout An ExotiC spECiEs, you CAn sAFEly BEt thE spEAkEr isn’t An ECologist. this is A nAmE For A rEsiDEnt oF An EstABlishED Community thAt wAs DEliBErAtEly or ACCiDEntAlly movED From its homE rAngE AnD BECAmE EstABlishED ElsEwhErE. unlikE most imports, whiCh CAn’t tAkE holD outsiDE thEir homE rAngE, An ExotiC spECiEs pErmAnEntly insinuAtEs itsElF into A nEw Community.
somEtimEs thE ADDitions ArE hArmlEss AnD EvEn hAvE BEnEFiCiAl EFFECts. morE oFtEn, thEy mAkE nAtivE spECiEs EnDAngErED spECiEs, whiCh By DEFinition ArE ExtrEmEly vulnErABlE to ExtinCtion. oF All spECiEs on thE rArE or EnDAngErED lists or thAt rECEntly BECAmE ExtinCt, ClosE to 70 pErCEnt owE thEir prECArious ExistEnCE or DEmisE to DisplACEmEnt By ExotiC spECiEs. two ExAmplEs ArE inCluDED hErE to illustrAtE thE proBlEm.
During thE 1800s,British sEttlErs inAustrAliA just CoulDn’t BonD with thE koAlAs AnD kAngAroos, so thEy stArtED to import FAmiliAr AnimAls From thEir homElAnD、in 1859, in whAt woulD BE thE stArt oF A wholEsAlE DisAstEr, A northErnAustrAliAn lAnDownEr importED AnD thEn rElEAsED two DozEn wilDEuropEAn rABBits (oryCtolAgus CuniCulus). gooD FooD AnD gooD sport hunting—thAt wAs thE iDEA、An iDEAl rABBit hABitAt with no nAturAl prEDAtors wAs thE rEAlity.
six yEArs lAtEr, thE lAnDownEr hAD killED 20,000 rABBits AnD wAs BEsiEgED By 20,000 morE. thE rABBits DisplACED livEstoCk, EvEn kAngAroos. nowAustrAliA hAs 200 to 300 million hippityhopping through thE southErn hAlF oF thE Country. thEy ovErgrAzE pErEnniAl grAssEs in gooD timEs AnD strip BArk From shruBs AnD trEEs During Droughts. you know whErE thEy’vE BEEn; thEy trAnsForm grAsslAnDs AnD shruBlAnDs into EroDED DEsErts. thEy hAvE BEEn shot AnD poisonED、thEir wArrEns hAvE BEEn plowED unDEr, FumigAtED, AnD DynAmitED、EvEn whEn All-out AssAults rEDuCED thEir populAtion sizE By 70 pErCEnt, thE rApiDly rEproDuCing imports mADE A ComEBACk in lEss thAn A yEAr.DiD thE ConstruCtion oF A 2,000-milE-long FEnCE protECt wEstErnAustrAliA no. rABBits mADE it to thE othEr siDE BEForE workErs FinishED thE FEnCE.
→ in 1951, govErnmEnt workErs introDuCED A myxomA virus By wAy oF milDly inFECtED southAmEriCAn rABBits, its normAl hosts. this virus CAusEs myxomAtosis. thE DisEAsE hAs milD EFFECts on southAmEriCAn rABBits thAt CoEvolvED with thE virus But nEArly AlwAys hAD lEthAl EFFECts on o. CuniCulus.Biting insECts, mAinly mosquitoEs AnD FlEAs, quiCkly trAnsmit thE virus From host to host. hAving no CoEvolvED DEFEnsEs AgAinst thE novEl virus, thEEuropEAn rABBits DiED in DrovEs.But, As you might ExpECt, nAturAl sElECtion hAs sinCE FAvorED rApiD growth oF populAtions oF o. CuniCulus rEsistAnt to thE virus.
→ in 1991, on An uninhABitED islAnD in spEnCEr gulF,AustrAliAn rEsEArChErs rElEAsED A populAtion oF rABBits thAt thEy hAD injECtED with A CAlCivirus. thE rABBits DiED quiCkly AnD rElAtivEly pAinlEssly From BlooD Clots in thEir lungs, hEArts, AnD kiDnEys. in 1995, thE tEst virus EsCApED From thE islAnD, possiBly on insECt vECtors. it hAs BEEn killing 80 to 95 pErCEnt oF thE ADult rABBits inAustrAliAn rEgions.At this writing, rEsEArChErs ArE now quEstioning whEthEr thE CAlCivirus shoulD BE usED on A wiDEsprEAD sCAlE, whEthEr it CAn jump BounDAriEs AnD inFECt AnimAls othEr thAn rABBits (suCh As humAns); AnD whAt thE long-tErm ConsEquEnCEs will BE.
A、vinE CAllED kuDzu (puErAriA loBAtA) wAs DEliBErAtEly importED From jApAn to thE unitED stAtEs, whErE it FACEs no sErious thrEAts From hErBivorEs, pAthogEns, or CompEtitor plAnts. in tEmpErAtE pArts oFAsiA, it is A wEll-BEhAvED lEgumE with A wEll-DEvElopED root systEm. it sEEmED likE A gooD iDEA to usE it to Control Erosion on hills AnD highwAy EmBAnkmEnts in thE southEAstErn unitED stAtEs.
【单选题】 In the metals industry, hydrogen is used to prevent metals from tarnishing while undergoing__________.
A．treated by heat
B．heat treatments
C．by heat treatments
D．heat-treated
A．treated by heat
B．heat treatments
C．by heat treatments
D．heat-treated
【单选题】 Why are marine organisms good candidates for fossilization
A．they have more fleshy structures than land organisms
B．It is likely that they will be buried rapidly
C．The water environment speeds the decay caused by bacteria
D．it takes longer for them to be preserved
A．they have more fleshy structures than land organisms
B．It is likely that they will be buried rapidly
C．The water environment speeds the decay caused by bacteria
D．it takes longer for them to be preserved
【单选题】 From 1949 onward, the artist Georgia O’ Keeffe made New Mexico ______.
A．her permanent residence was
B．where her permanent residence
C．permanent residence for her
D．her permanent residence
A．her permanent residence was
B．where her permanent residence
C．permanent residence for her
D．her permanent residence
【单选题】 Compared to the tail of electrically charged atoms, the tail of neutral dust particles is relatively
A．( long
B．( curved
C．( unpredictable
D．( bright
A．( long
B．( curved
C．( unpredictable
D．( bright
【单选题】 (Many folk songs) were originated to accompany (manual) work (or to) mark a specific (ceremonies).
A．Many folk songs
B．manual
C．or to
D．ceremonies
A．Many folk songs
B．manual
C．or to
D．ceremonies
【单选题】 The word "momentarily" in line 20 is closest in meaning to
A．( effortlessly
B．( briefly
C．( electronically
D．( gradually
A．( effortlessly
B．( briefly
C．( electronically
D．( gradually
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