大学英语四级考试备考练习.docx

大学英语四级考试备考练习.docx

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大学英语四级考试备考练习

2010年大学英语四级考试备考练习

PartIWriting

（30minutes）

Directions:

Forthispart,youareallowed30minutestowriteashortessayentitled“AreElectricBikesaMustforMiddleSchoolStudents?

”Youshouldwriteatleast120wordsfollowingtheoutlinegivenbelowinChinese:

1.越来越多的中学生开始骑电动车并享受电动车给他们带来的便利；

2.但是电动车在给同学们带来便利的同时，对他们的安全也造成了威胁；

3.我认为，电动车……

PartIIReadingComprehension（SkimmingandScanning）（15minutes）

Directions:

Inthispart,youwillhave15minutestogooverthepassagequickly.Forquestions1-7,choosethebestanswerfromthefourchoicesmarkedA）,B）,C）andD）.Forquestions8-10,completethesentenceswiththeinformationgiveninthepassage.

FluPrevention:

5CriticalLessonsfromHistoryandWhatTheyMeanToday

It’simpossibletopredictwhatafluvirusisgoingtodo.Buthistoryoffersacriticalguideanyway,showingpublichealthofficialswhichmovesarelikelytopayoffinthebattleagainstthedisease.

1.Whatworks:

Shuttingthingsdown

Intheso-calledSpanishfluepidemicof1918-1919,threewavesofthediseaseswepttheworld,killingapproximately50millionpeople,including500,000Americans.ButMinneapolisandMilwaukeesufferedfewerthan3deathsper1,000people—lessthanhalftherateincitieslikeBaltimore,BostonandSanFrancisco.

Onereason:

TheMidwesterncitiesquarantinedthesick,closedschoolsandchurches,andbannedpublicgatherings.Anothercity,Gunnison,Colorado,escapedtheplaguebyphysicallyblockingthemainroadsintotown.Ontheotherhand,Philadelphiaofficialsrefusedtobanmeetingsorparadesongroundsofpatriotism,andcitynewspapersdownplayedtheflu’sseverity.Theresult:

Philadelphiahadoneofthehighestdeathratesinthecountry.Thesemeasureshavecost,ofcourse:

Closingschoolscouldforcesomanyparentstomissworkthatitcouldhamstringtheeconomy.Ifthevirusdoesn’tintensify,U.S.officialssay,theiradviceistokeepschoolsopenasmuchaspossible.

Take-homelesson:

Askyourkids’principalwhatwouldtriggeraschoolclosing,andbeprepared.Strategizewithfriendsaboutsharingchildcareiftheneedarises,ortalktoyourbossaboutworkingfromhome.

2.Whatworks:

Vaccinating（给……接种疫苗）kidsearly

WhogetsflushotsintheUnitedStates?

Oldpeople,ofcourse—they’vebeenthefocusoffluvaccinecampaignssincethe1960s.Butanimportantwaytoincreasetheirprotection,ironically,istovaccinatetheirchildrenandgrandchildren.

Thereason:

Anolderperson’simmunesystemdoesn’trespondefficientlytothefluvaccine,soit’sonlypartiallyprotective.Thesamevaccinecreatesamuchstrongerimmunityintheyoung.What’smore,kidsaremorelikelythanotherstobecomesilentcarriers,transmittingthevirusforuptotendaysaftersymptomsdisappear.

Take-homelesson:

It’sworthgettingyourfamilyvaccinatedevenifthefluseemsmild,ifonlybecauseinsomepandemics,thesecondwavehasbeendeadlierthanthefirstone.TheCentersforDiseaseControlandPrevention（orCDC）advocatesthatchildrenandyoungadultsbeamongthefirstgroupofpeopletoreceivethevaccine.Someoftheothersontheprioritylistincludepeoplewithchronicillnesses,likediabetesandheartorlungdisease,andpregnantwomen,allofwhomareathighriskofcomplications（并发症）ofthepandemicflu.

3.Whatworks:

Avaccinethatcan’tbefooled

Everyyear,peopleunluckyenoughtobeinfectedwiththefludevelopantibodiesthatwillkeepthemsafeifthey’reexposedtothesamevirusinthefuture.Butgradually,thevirusmutates（变异）—sometimesenoughtofoolthoseantibodiesandinfectthepeopleagain.Asaresult,virologistsandpublichealthofficialsarealwaysplayingcatch-up.InFebruary,theypredictwhichstrainsofviruswillcirculateinthefall,anddrugcompaniespreparevaccinestoproduceimmunitytothosespecificstrains.Inevitably,thepredictionssometimesprovewrong.“Itwouldbeahugeadvantagetohaveauniversalvaccine,”saysE.JohnWherry,PhD,oftheWistarInstituteinPhiladelphia—avaccinethatwouldprotectyearinandyearout,byaimingatpiecesofthevirusthatdon’tchange.Likehundredsofscientistsaroundtheworld,Dr.Wherryistryingtodevelopsuchavaccine.It’sstillalongwayoff,butapartialsolutionmayalreadybeavailable.Whenavaccineismixedwithanadjuvant（achemicalmixturethatstimulatestheimmunesystem）,ashasbeendoneinstudiesofbirdfluvaccine,itseemstoprotectagainstavarietyoffluviruses.Soevenifthecurrentvirusmutates,anadjuvantvaccinemightstillprovideashield.

Take-homelesson:

Adjuvantvaccinesaren’tlicensedintheUnitedStates,andtheFoodandDrugAdministrationprobablywon’tletususethemunlessthevirusbecomesmoreserious.（However,thereseemstobesomenaturalcross-protectiongoingonwiththisvirus:

Thoughnewtohumanimmunesystems,itdoesn’tseemtoinfectpeopleover60veryoften.Theearlierfluvirustaughttheirimmunesystemsawaytodefendagainstthecurrentone.）Thebestwaytoboostyourprotection:

Washyourhandsoften—thefluviruscansurviveupto48hoursonsurfaces.Getplentyofsleepandtakeregularexercise;yourimmunesystemdependsonthem.

4.Whatworks:

Ahealthyrespectforsideeffects

OnebalmynightinNovember1976,39-year-oldJuneE.Robertsfeltcoldnessinherfingersasshetriedtopaysomebills.Itwastwoweeksaftershe’dgottenavaccineagainstthecountry’sfirstoutbreakofswineflu.Thenextmorning,theMcLean,Virginia,tennisinstructorcouldn’tgetoutofbed.Formorethanamonth,Robertscouldn’teat,moveherlimbs,orevenclosehereyes.Sherecovered,slowly,butwasneverabletoplaytenniswellagain.RobertshadGuillain-Barrésyndrome,adisorderinwhichantibodiesattackthepatient’sownnervoussystem.Itwastriggeredbythefluvaccinesheandmorethan40millionotherAmericanshadgotten.NoonewasentirelysurewhythevaccinecausedGuillain-Barrésyndrome,butitaffectedmorethan500peopleandkilledabout25.（Thefearedswinefluepidemicnevermaterializedthatyear.）Theepisodehashighlightedapointfamiliartopublichealthworkers:

Preventionnevercomeswithoutrisk.

Take-homelesson:

TheCDCisaddingstaffandcomputertrackingsystemstolookforpossibleproblemswiththevaccine,soifanyunexpecteddangersshowup,they’llbeflaggedquickly.Butexpertsemphasizethatit’srareforanyfluvaccinetohaveserioussideeffects,andtheydon’texpecttoseeanywiththisvaccine.Specifically,theydon’tanticipatecasesofGuillain-Barrésyndrome,becauseofmajordifferencesbetweenthisyear’sswinefluvirusandtheonethatpromptedthe1976vaccine.

5.Whatworks:

Localcontrol

Althoughyou’rehearingalotfromtheCDCandtherestofthefederalgovernment—nottomentiontheWorldHealthOrganization—abouthowtorespondtotheflu,therealdecisionswillbemadebystatesandlocalities.“Everythingislocal,”saysformerCDCdirectorDavidSencer,MD.“Thefederalgovernmentcangiveguidance,butimplementationhastobelefttothelocalcommunities.Whichkeyemergencyworkersshouldbeimmunized?

IfyouaskmydaughterinMinneapolis,she’llsayit’sthesnowplowdrivers.Ifyoucan’tmovearoundthecity,youcan’ttakecareofsickkids.”Thedownsideisthatwithstates,cities,andevenschooldistrictsformulatingtheirownpolicies,we’relikelytohearconflictingadvice.

Take-homelesson:

Takeadeepbreathandgetpreparedforsomeconfusion.Tohelpsortthroughthings,youcanfindhelpfulinformationatcentralclearinghouses.

1.Accordingtothepassage,MinneapolisandMilwaukee________.

A）didverywellincombatingtheSpanishflu

B）didn’tdoagoodjobfightingtheSpanishflu

C）didnothingtostrugglewiththeSpanishflu

D）refusedtobanmeetingsorparades

2.Whatshouldparentsdoiftheirchildren’sschoolsareclosed?

A）Asktheirkids’principalwhentheschoolswillreopen.

B）Talktotheirbossaboutraisingtheirsalarytotakecareofkids.

C）Preparetoalternatewiththeirfriendsintakingcareofkids.

D）Quittheirjobsandstayathomewiththeirchildren.

3.ManypeopleshouldreceivethevaccinefirstEXCEPT________.

A）peoplewithchronicillnesses

B）childrenandyoungadults

C）pregnantwomen

D）oldpeople

4.Theunderlinedphrase“playingcatch-up”mostprobablymeans“________”.

A）playingcomputergames

B）playingcards

C）predictingepidemicdiseases

D）catchingepidemicpatients

5.Itwouldbegreattohaveauniversalvaccinebecause___________.

A）itwouldprotectpeopleyearinandyearout

B）theexpertswouldn’tneedtopredictwhichviruswillcirculate

C）theviruswouldnotmutateandinfectpeopleagain

D）peoplewouldn’tneedtoreceivethevaccineanymore

6.Youmayimproveyourimmunesystemthroughthefollowingways,EXCEPT_______.

A）washingyourhandsoften

B）gettingplentyofsleep

C）eatingabalanceddiet

D）gettingregularexercise

7.ThestoryofJuneE.Robertsisgivento__________.

A）provethisyear’sswinefluvirusismild

B）criticizetheU.S.governmentofficials

C）stressthatpreventionnevercomeswithoutrisk

D）implythatpeopleshouldn’treceivethevaccine

8.____________________schoolsandbanningpublicgatheringsareeffectivewaystofightagainstafluvirus.

9.Expertsclaimthatnotallfluvaccineshaveserious______________.

10.Althoughthefederalgovernmentcangiveguidance,implementationhastobeleftto_________________.

PartIIIReadingComprehension（ReadinginDepth）（25minutes）

■SectionA

Directions:

Inthissection,thereisapassagewithtenblanks.Youarerequiredtoselectonewordforeachblankfromalistofchoicesgiven