大学英语四级考试及答案模拟题三.docx

大学英语四级考试及答案模拟题三.docx

《大学英语四级考试及答案模拟题三.docx》由会员分享，可在线阅读，更多相关《大学英语四级考试及答案模拟题三.docx（24页珍藏版）》请在冰豆网上搜索。

大学英语四级考试及答案模拟题三

模拟题三

PartⅠWriting（30minutes）

Directions:

Forthispart,youareallowed30minutestowriteacompositionon

thetopicDormitoryLife.Youshouldwriteatleast120wordsfollowingtheoutline

givenbelowinChinese:

DormitoryLife

1.大学宿舍的集体生活是全新的体验。

2.宿舍生活与在家生活的不同之处。

3.宿舍生活利与弊。

PartIIReadingComprehension（SkimmingandScanning）

Directions:

Inthispart,youwillhave15minutestogooverthepassagequickly

andanswerthequestionsonAnswersheet1.

TestingTimes

Researchersareworkingonwaystoreducetheneedforanimalexperiments,

butnewlawsmayincreasethenumberofexperimentsneeded.Thecurrent

situation

Inanidealworld,peoplewouldnotperformexperimentsonanimals.Forthe

people,theyareexpensive.Fortheanimals,theyarestressfulandoftenpainful.

Thatidealworld,sadly,isstillsomewayaway.Peopleneednewdrugsand

vaccines.Theywantprotectionfromthetoxicityofchemicals.Thesearchforbasic

scientificanswersgoeson.Indeed,theEuropeanCommissionisforgingaheadwith

proposalsthatwillincreasethenumberofanimalexperimentscarriedoutinthe

EuropeanUnion,byrequiringtoxicitytestsoneverychemicalapprovedforuse

withintheunion'sbordersinthepast25years.

Already,thecommissionhasidentified140,000chemicalsthathavenotyet

beentested.Itwants30,000ofthesetobeexaminedrightaway,andplanstospend

between~4billion—8billion（$5billion—10billion）doingso.Thenumberof

animalsusedfortoxicitytestinginEuropewillthus,expertsreckon,quintuple（翻五

倍）fromjustoverlmayeartoabout5m,unlesstheyaresavedbysomedramatic

advancesinnon-animaltestingtechnology.Atthemoment,roughly10%of

Europeananimaltestsareforgeneraltoxicity,35%forbasicresearch,45%fordrugs

andvaccines,andtheremaining10%avarietyofusessuchasdiagnosingdiseases.

Animalexperimentationwillthereforebearoundforsometimeyet.Butthe

searchforsubstitutescontinues,andlastweekendtheMiddleEuropeanSocietyfor

AlternativeMethodstoAnimalTestingmetinLinz,Austria,toreviewprogress.

Agoodplacetostartfindingalternativesfortoxicitytestsistheliver--theorgan

responsibleforbreakingtoxicchemicalsdownintosafermoleculesthatcanthenbe

excreted.Twofirms,onelargeandonesmall,toldthemeetinghowtheywereusing

humanlivercellsremovedincidentallyduringsurgerytotestvarioussubstancesfor

long-termtoxiceffects.

Onewayoutoftheproblem

PrimeCyte,thesmallfirm,growsitscellsinculturesoverafewweeksanddoses

themregularlywiththesubstanceunderinvestigation.Thecharacteristicsofthe

cellsarecarefullymonitored,tolookforchangesintheirmicroanatomy.

Pfizer,thebigfirm,alsodosesitsculturesregularly,butratherthanstudying

individualcellsindetail,itcountscellnumbers.Ifthenumberofcellsinaculture

changesafterasampleisadded,thatsuggeststhechemicalinquestionisbadforthe

liver.

Inprinciple,thesetechniquescouldbeappliedtoanychemical.Inpractice,

drugs（and,inthecaseofPrimeCyte,foodsupplements）aretopofthelist.Butthat

mightchangeifthecommissionhasitsway:

those140,000screeningslooklikea

lucrativemarket,althoughnobodyknowswhetherthenewtestswillbereadyfor

useby2009,whenthecommissionproposesthattestingshouldstart.

Othertissues,too,canbetestedindependentlyofanimals.Epithelix,asmall

firminGeneva,hasdevelopedanartificialversionoftheliningofthelungs.

AccordingtoHuangSong,oneofEpithelix'sresearchers,thefirm'sculturedcells

havesimilarmicroanatomytothosefoundinnaturallunglinings,andrespondinthe

samewaytovariouschemicalmessengers.Dr.Huangsaysthattheycouldbeusedin

long-termtoxicitytestsofairbornechemicalsandcouldalsohelpidentifytreatments

forlungdiseases.

Theimmunesystemcanbemimickedandtested,too.ProBioGen,acompany

basedinBerlin,isdevelopinganartificialhumanlymphnode（淋巴结）which,it

reckons,couldhavepreventedtheneardisastrousconsequencesofadragtrialheld

inBritainthreemonthsago,inwhich（despitethedraghavingpassedanimaltests）

sixmensufferedmultipleorganfailureandnearlydied.Thedrugthemenwere

givenmadetheirimmunesystemshyperactive.Sucharesponsewould,thefirm's

scientistsreckon,naveteenidentifiedbytheirlymphnode,whichismadefromcells

thatprovoketheimmunesystemintoaresponse.ProBioGen'slymphnodecould

thusworkbetterthananimaltesting.Asecondalternative

Anotherwayofcuttingthenumberofanimalexperimentswouldbetochange

thewaythatvaccinesaretested,accordingtoCoenraadHendriksenofthe

NetherlandsVaccineInstitute.Atthemoment,allbatchesofvaccinearesubjectto

thesamebatteryoftests.Dr.Hendriksenarguesthatthisisover-rigorous.When

newvaccineculturesaremade,belt-and-bracestestsobviouslyneedtobeapplied.

Butifabatchofvaccineisderivedfromanexistingculture,hesuggeststhatitneed

betestedonlytomakesureitisidenticaltothebatchfromwhichitisderived.That

wouldrequirefewertestanimals.

Allthissuggeststhatthoughthereisstillsomewaytogobeforedrugs,vaccines

andothersubstancescanbetestedroutinelyoncellsratherthanliveanimals,useful

progressisbeingmade.Whatishardertoseeishowtheuseofanimalsmightbe

banishedfromfundamentalresearch.Weighingthebalance

Inbasicscientificresearch,wheretheobjectistounderstandhow,say,the

brainworksratherthantodevelopadrugtotreatbraindisease,thewholeanimalis

oftennecessarilytheobjectofstudy.Indeed,insomecases,scientificadvancesare

makinganimaltestsmorevaluable,ratherthanless.Geneticmodificationtechniques

meanthatmiceandratscanberemodelledtomakethemexhibitillnessesthatthey

wouldnotnormallysufferfrom.Also,genesforhumanproteinscanbeaddedto

them,sothatanimaltestswillmorecloselymimichumanresponses.Thisoffersthe

opportunitytounderstandhumandiseasesbetter,andtoscreentreatmentsbefore

humantrialsbegin.However,theverycreationofthesemutants（突变异种）counts

asananimalexperimentinitsownright,sothenumberofexperimentsisincreasing

onceagain.

Whatisbadnewsforrodents,though,couldbegoodnewsforprimates.Apes

andmonkeysbelongtothesamegroupofmammalsashumans,andarethusseen

asthebestsubjectsforcertainsortsofexperiment.Totheextentthatrodentscan

be"humanised",thenumberofprimateexperimentsmightbereduced.

Somepeople,ofcourse,wouldliketoseethemeliminatedaltogether,

regardlessoftheeffectonusefulresearch.OnJune6ththeBritishUnionforthe

AbolitionofVivisection,ananimal-rightsgroup,calledfortheuseofprimatesin

researchtobebanned.Forgreatapes,thishasalreadyhappened.Britain,Austria,

theNetherlands,NewZealandandSwedenhaveendedexperimentson

chimpanzees,gorillas,bonobosandorang-utans.Experimentsonmonkeys,though,

arestillpermitted.Andsomecountrieshavenotbannedexperimentsonapes.In

America,forexample,about1,000chimpanzeesayearareusedinresearch.

Thisisadifficultarea.Greatapesareman'sclosestrelatives,havingparted

companyfromthehumanfamilytreeonlyafewmillionyearsago.Henceitcanbe

（andis）arguedthattheyareindispensableforcertainsortsofresearch.Ontheother

hand,arecentstudybyAndrewKnightandhiscolleaguesatAnimalConsultants

International,ananimal-advocacygroup,castsdoubtontheclaimthatapesareused

onlyforworkofvitalimportancetohumanity.Importantpaperstendtogetcitedas

referencesinsubsequentstudies,soMr.Knightlookedintothenumberofcitations

receivedby749scientificpaperspublishedasaresultofinvasiveexperimentson

captivechimpanzees.Halfhadreceivednotasinglecitationuptotenyearsafter

theiroriginalpublication.

Thatisdamning.Animalexperimentsareneededfortheadvanceofmedical

science,nottomentionpeople's

safety.Butifscientistsaretokeepthesympathyofthepublic,theyneedtodo

betterthanthat.

1.Thepassagesummarizesharmfuleffectsofanimalexperiment.However,as

animalexperimentisindispensableinanumberofareas,itmightnotbestoppedor

replacedbyotheralternatives.

2.Animalexperimentsareneededinresearchtofindnewdrugsandvaccines,

andtofindwaysofprotectionfromthetoxicityofchemicals.

3.Itispredictedbyexpertsthatthenumberofanimalsusedfortoxicitytesting

inEuropewillquintupleduetoaplantohavealargevarietyofchemicaltested.

4.Peoplearetryingtofindalternativestoanimaltesting,andtheystartedwith

liver.

4.PrimeCyteandPfizerbegantofindalternativestoanimaltestingbecause

theywereadvocatesofanimalprotection.

5.Itisfoundthattissuesfromliver,lung,andimmunesystemcanallbetested

independentlyofanimals.

6.Althoughthereismorethanonealternativetoanimalexperiment,thereis

stillconcernoverhowtoeliminateanimaltestinginfundamentalresearch.

7.Inbasicscientificresearch,theobjectistounderstandhow,say,thebrain

worksratherthantodevelopadrugto______braindisease.

8.Indeed,insomecases,scientificadvancesaremakinganimaltests

___________

9.Recently,ananimal-advocacygroupcastsdoubtonthescientists'claimthat

apesareusedonlyfor__________

PartIVReadingComprehension（ReadinginDepth）

SectionA

Directions:

Inthissection,thereisapassagewithtenblanks.Youarerequired

toselectonewordforeachblankfromalistofchoicesgiveninawordbank

followingthepassage