四级模拟03.docx
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四级模拟03.docx
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四级模拟03
PartI.Writing
Directions:
Forthispart,youareallowed30minutestowriteacompositiononthetopic:
StressandTension.Youshouldwritenolessthan120wordsandyourcompositionshouldbebasedontheoutline(giveninChinese)below.
1.现代生活充满压力
2.压力的种种迹象
3.如何减轻压力
PartII.SkimmingandScanningReading
Directions:
Inthispart,youwillhave15minutestogooverthepassagequicklyandanswerthequestionsonAnswerSheet1.Forquestions1-7,markY(forYES)ifthestatementagreeswiththeinformationgiveninthepassage;N(forNO)ifthestatementcontradictstheinformationgivenintheinthepassage;NG(forNOTGIVEN)iftheinformationisnotgiveninthepassage.For8-10,completethesentenceswiththeinformationgiveninthepassage.
ThePlantHunter
Theteacherandstudentsitcross-legged,facingeachotherontheflooroftheopen-sidedhutinWesternSamoa.Behindthemtherain-forestrisestothesummitofaninactivevolcano.TheteacherisSalomeIsofea,a30year-oldhealer,andherstudentisanAmericannamedPaulAlanCox.ButCoxisnotanordinarystudent—heisabotanyprofessoratBrighamYoungUniversityinUtahandaworldauthorityonmedicinalplants.
Salomeisexplainingatraditionalcureforpterygium(翼状片),aneyeafflictioncommontothetropicsinwhichvisiongraduallybecomesobscuredasalayeroftissueslowlycoversthecornea(角膜).ThetraditionalcureusedbyhealersisleavesofCentallaasiatica,avinethatgrowsalongtheground,whichSalomechewsintoapoultice(膏状药),smearsonaclothandthenplacesasacompressontheafflictedeyeforthreeconsecutivenights.
MomentslikethisaretypicalofCox'sexperienceashescourstheworld'splantsinsearchofthosethatmaybenefitwesternmedicine.CoxhasspentmanyyearsinSamoainterviewingorapprenticing(使当学徒)himselftobeatraditionalhealer.HehasalsotraveledthroughouttheSouthPacific,aswellasinSoutheastAsia,SouthAmerica,EastAfricaandasfarnorthasSweden'sLapland.InSamoaalone,healershaveledhimto74medicinalplantswhichmightproveuseful.
Samoanhealersmixpoulticesandherbalremediesfromtheleaves,barksandrootsoflocalplants,usingthemforconditionsthatrangefromhighfevertoappendicitis(阑尾炎).
Amongthemarerootofago(Curcumalonga)forrashes,leavesofthekuavatree(Psidiumguajava)fordigestiveproblems,andthebarkofvavae(Ceibapentandra)forbreathingdifficulties.Virtuallyallthehealersarewomenwholearnedtheirartfromtheirmothers,whointurnlearneditfromtheirmothers.Nowknowledgeoftherecipesandtheirused,andeventhelocationoftheplantsintheforests,isendangeredasmoreandmoredaughtersrejectthelongapprenticeshipsinfavorofusingWesternpillsandcreams.
Forthisreason,thediscoveryofyoungpracticinghealerslikeSalomedelightsCox,whobelievesthatonlypeoplelikehercanpreventthelossofcenturiesofknowledge.IfhecancarrySalome'sknowledgetothedevelopedworldintheformofplantswhosevariouschemicalcompoundsmighthelpcombatincurablediseases—notablycancer,AIDSandAlzheimer's—themotivationtosavetheSamoanrainforest,andallforests,willbethatmuchstronger.
Fewerthan1%oftheworld's265,000floweringplants,mostofwhichinhabittropicalregions,havebeentestedfortheireffectivenessagainstdisease."Wehaven'tevenscratchedthesurface—noteveninourownbackyard,"saysJimMiller,directoroftheMissouriBotanicalGarden'snatural-productsprogram.YetnearlyaquarterofprescriptiondrugssoldintheUSarebasedonchemicalsfromjust40plantsspecies.Morphine,forexample,isderivedfrompoppiesandmedicinessuchasvincristine(长春新碱)andvinblastine(长春碱),isolatedfromtherosyperiwinkle(长春花属植物),helptreatcancers,includingHodgkin'sdiseaseandsomeleukemias(白血病).Curare,takenfromseveralpoisonousAmazonianplantsandoftenusedinthetipsofhuntingarrows,isusedindrugsthatcauseanesthesia,andreserpine(利血平),anextractofthesnakerootplant,traditionallyusedinAsiatocounteractpoisonoussnakebites,isthebasisofseveraldrugstoreduceanxietyandabnormallyhighbloodpressure.
Thedrivetocollectandscreenmorenaturalproductsfortheirmedicinaleffectsisintensifyingandthisisgoodnewsforbiologistsandenvironmentalistsconcernedaboutthedwindlingoftheplanet'sbiodiversity,mostlyconcentratedinawidebandaroundtheequator.Humanactivity,fromfarmingtologgingandroadbuilding,ismakingthisbandevernarrower,drivingnumerousspeciestoextinctionevenbeforetheyhavebeendiscovered."Iseeethnobotany—thestudyoftherelationshipbetweenpeopleandplants—asthekeytothepreservationofthisvastcollectionofspeciesaswellasapathwaytohaltingmanydiseases,"saysCox.
MajortechnologicaladvancesinscreeningprocesseshavehelpedCoxandotherethnobotanistsconsiderably.Pharmacologistmustanalyzebetween10,000and17,000chemicalcompoundsbeforefindingonewiththepotentialtobetestedforefficacyinhumans.Untilrecently,animaltestingandclinicaltrialsofasingledrugrequiredanaverage12yearsofresearchandcostupto300milliondollars.Butinitialscreeningcannowbedoneinamatterofdayswithoutusinganimals.Molecularbiologistsareabletoisolateenzymes(酶)thatcantriggerhumandiseases,thenexposethoseenzymestoaplant'schemicalcompounds.Ifaplantextractblockstheactionofaparticularenzyme—say,onethatcausesaskindisease—theyknowtheplanthasdrugpotential.Byextractingspecificchemicalsfromtheleaves,rootsorbarkinaseriesofexperimentsandtestingeachsampleindividually,scientistscandeterminewhichoftheplant'sthousandsofcompoundsactuallyblockstheenzyme.
Asaresultoftheseadvances,about100UScompaniesaresearchingoutplants.Drugcompaniesandscientificinstitutionsareworkingtogetheronfieldresearchallovertheworld,racingtostudyasmanynaturalsubstancesaspossiblebeforethey,orthenativepeoplewhousethem,disappear.SomeworkwiththehandfulofethnobotanistslikeCoxtosearchoutdrugcandidatesbasedontheirknowledgeofnativepeoples;othersuseabroaderapproach,mass-collectingplantswhosechemicalcompoundsmightcontributetonewdrugs.
Coxbelievesthatethnobotanicalfieldresearchprovidesamuchbetterorganizedwayoflocatingplantsthathavemedicalpotentialthanrandomcollecting."Nativepeoplehavebeentestingplantsonpeopleforthousandsofyears,"hesays.CoxrecentlydiscoveredthatHomalanthusnutans—arainforesttreewhosebarkSamoanshaveusedforcenturiesasacureforhepatitis(肝炎)—containedacompoundwhichappearedtoinhibitgrowthoftheAIDSvirusandwhichisnowundergoingfurthertestingforpossibleuseinthefuture.
Coxhaslocatedthreeothermedicallypromisingplants.Twooftheplants,usedbySamoanstocontrolskindiseases,arebeinginvestigatedbyadrugcompany.Thethirddoublesthelifespanofinfection-fightingTlymphocytes(T型淋巴球)inthetesttube;itseffectinthehumanbodyisnotyetknown.
However,Coxismorethanahealer'sapprentice.HeknowsthatiftherainforestsofSamoacontinuetodisappear,hundredsofpotentialdrugshiddentheremayneverbefound.Todatemorethan80%ofthelowlandrainforesthasalreadybeenloggedandCox'saimistooffercash-poorwesternSamoansanalternativetosellingouttologgers.
Inrecentyearshehassetupacharitablefoundation,theSeacologyFoundation,basedatBrighamYoungtoprovidemoneyfortheSamoanvillagerstoenablethemtobuildschoolsandhospitalswithouthavingtoselltheirforeststologgingcompanies.InthevillageofFalealupo,aseriesofplatformsandawalkwayhighinthetreeshavebeenconstructedtoattractecotourists.Theincomeearnedfromtouristgroupsvisitingtheforesthashelpedthevillagesunderstandthewealthoftheirheritage,andCoxhopestheywillbeencouragedtopreserveitratherthansellit.Samoanshavetraditionallyusedtheforestforhunting,collectingmedicinalplantsandharvestingwildfruitsanditisinthisinterplaybetweennatureandculturethatCoxseeshopeforconservationandthefutureofethnobotany."Wecan'tsavetheforestwithoutsavingtheculture,"hesays,"andwecan'tsavetheculturewithoutsavingtheforest."
1.VeryfewofthehealersinSamoaarewomen.
2.Mostoftheworld'splantspecieslieintropicalareas.
3.TherainforesttreeHomalanthusnutanswasonlyrecentlydiscovered.
4.About40%oftheworld's265,000floweringplantshavebeentestedfortheireffectivenessagainstdisease.
5.Coxbelievesthedisappearanceoftherainforestswillleadtothedisappearanceoflocalcultures,andalsothelossofmanypotentialplant-basedmedicines
6.EcotourismhashelpedtheSamoanvillagerstorealizehowprecioustherainforestsare.
7.ThegoaloftheSeacologyFoundationaretoprovidefinancialaidtoSamoanssothattheycanstartnewenterprisesandimproveeconomicdevelopment.
8.Theword"them"inthefirstsentenceinParagraph5refersto_______.
9.About100UScompaniesaresearchingoutplantsbecauseof_______.
10.Coxconsidersethnobotanyisnotonlythekeytothepreservationofthevastcollectionofspecies,butalsothepathwayto_______.
PartIII.ListeningComprehension(35minutes)
SectionA
Directions:
Inthissection,youwillhear8shortconversationsand2longconversations.Attheendofeachconversation,oneormorequestionswillbeaskedaboutwhatwassaid.Boththeconversationandthequestionswillbespokenonlyonce.Aftereachquestiontherewillbeapause.Duringthepause,youmustreadthefourc
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- 模拟 03