三极管有两个PN结,二极管有一个PN结,所以两个二极管可以代替一个三极管。

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2、错误
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newweapontofightcancer

1.Britishscientistsarepreparingtolaunchtrialsofaradicalnewwaytofightcancer,whichkillstumoursbyinfectingthemwithviruseslikethecommoncold.

2.Ifsuccessful,virustherapycouldeventuallyformathirdpillaralongsideradiotherapyandchemotherapyinthestandardarsenalagainstcancer,whileavoidingsomeofthedebilitatingside-effects.

3.LeonardSeymour,aprofessorofgenetherapyatOxfordUniversity,whohasbeenworkingonthevirustherapywithcolleaguesinLondonandtheUS,willleadthetrialslaterthisyear.CancerResearchUKsaidyesterdaythatitwasexcitedbythepotentialofProfSeymour’spioneeringtechniques.

4.Oneofthecountry’sleadinggeneticists,ProfSeymourhasbeenworkingwithvirusesthatkillcancercellsdirectly,whileavoidingharmtohealthytissue."Inprinciple,you’vegotsomethingwhichcouldbemanytimesmoreeffectivethanregularchemotherapy,"hesaid.

5.Cancer-killingvirusesexploitthefactthatcancercellssuppressthebody’slocalimmunesystem."Ifacancerdoesn’tdothat,theimmunesystemwipesitout.Ifyoucangetavirusintoatumour,virusesfindthemaverygoodplacetobebecausethere’snoimmunesystemtostopthemreplicating.Youcanregarditasthecancer’sAchilles’heel."

6.Onlyasmallamountofthevirusneedstogettothecancer."Theyreplicate,yougetamillioncopiesineachcellandthecellburstsandtheyinfectthetumourcellsadjacentandrepeattheprocess,"saidProfSeymour.

7.Preliminaryresearchonmiceshowsthatthevirusesworkwellontumoursresistanttostandardcancerdrugs."It’saninterestingpossibilitythattheymayhaveanadvantageinkillingdrug-resistanttumours,whichcouldbequitedifferenttoanythingwe’vehadbefore."

8.Researchershaveknownforsometimethatvirusescankilltumourcellsandsomeaspectsoftheworkhavealreadybeenpublishedinscientificjournals.Americanscientistshavepreviouslyinjectedvirusesdirectlyintotumoursbutthistechniquewillnotworkifthecancerisinaccessibleorhasspreadthroughoutthebody.

9.ProfSeymour’sinnovativesolutionistomaskthevirusfromthebody’simmunesystem,effectivelyallowingthevirusestodowhatchemotherapydrugsdo-spreadthroughthebloodandreachtumourswherevertheyare.Thebighurdlehasalwaysbeentofindawaytodelivervirusestotumoursviathebloodstreamwithoutthebody’simmunesystemdestroyingthemontheway.

10."Whatwe’vedoneismakechemicalmodificationstothevirustoputapolymercoataroundit-it’sastealthviruswhenyouinjectit,"hesaid.

11.Afterthestealthvirusinfectsthetumour,itreplicates,butthecopiesdonothavethechemicalmodifications.Iftheyescapefromthetumour,thecopieswillbequicklyrecognisedandmoppedupbythebody’simmunesystem.

12.Thetherapywouldbeespeciallyusefulforsecondarycancers,calledmetastases,whichsometimesspreadaroundthebodyafterthefirsttumourappears."There’sanawfulstatisticofpatientsinthewest...withmalignantcancers;75%ofthemgoontodiefrommetastases,"saidProfSeymour.

13.Twovirusesarelikelytobeexaminedinthefirstclinicaltrials:adenovirus,whichnormallycausesacold-likeillness,andvaccinia,whichcausescowpoxandisalsousedinthevaccineagainstsmallpox.Forsafetyreasons,bothwillbedisabledtomakethemlesspathogenicinthetrial,butProfSeymoursaidheeventuallyhopestousenaturalviruses.

14.Thefirsttrialswilluseuncoatedadenovirusandvacciniaandwillbedeliveredlocallytolivertumours,inordertoestablishwhetherthetreatmentissafeinhumansandwhatdoseofviruswillbeneeded.Severalmoreyearsoftrialswillbeneeded,eventuallyalsoonthepolymer-coatedviruses,beforethetherapycanbeconsideredforuseintheNHS.Thoughtheapproachwillbeexaminedatfirstforcancersthatdonotrespondtoconventionaltreatments,ProfSeymourhopesthatonedayitmightbeappliedtoallcancers.

Questions1-6

Dothefollowingstatementsagreewiththeinformationgiveninthereadingpassage?Forquestions1-6write

TRUEifthestatementagreeswiththeinformation

FALSEifthestatementcontradictstheinformation

NOTGIVENifthereisnoinformationonthisinthepassage

1.Virustherapy,ifsuccessful,hasanadvantageineliminatingside-effects.

2.CancerResearchUKisquitehopefulaboutProfessorSeymour’sworkonthevirustherapy.

3.Viruscankillcancercellsandstopthemfromgrowingagain.

4.Cancer’sAchilles’heelreferstothefactthatvirusmaystaysafelyinatumorandreplicate.

5.Toinfectthecancercells,agooddealofvirusesshouldbeinjectedintothetumor.

6.Researchesonanimalsindicatethatviruscouldbeusedasanewwaytotreatdrug-resistanttumors.

Question7-9

Basedonthereadingpassage,choosetheappropriateletterfromA-Dforeachanswer.

7.Informationaboutresearchesonviruseskillingtumorcellscanbefound

(A)onTV

(B)inmagazines

(C)oninternet

(D)innewspapers

8.Totreattumorsspreadingoutinbody,researcherstryto

(A)changethebody’immunesystem

(B)injectchemotherapydrugsintobloodstream.

(C)increasetheamountofinjection

(D)disguisethevirusesonthewaytotumors.

9.Whenthechemicalmodifiedvirusintumorreplicates,thecopies

(A)willsoonescapefromthetumorandspreadout.

(B)willbewipedoutbythebody’simmunesystem.

(C)willbeimmediatelyrecognizedbytheresearchers.

(D)willeventuallystopthetumorfromspreadingout.

Questions10-13

Completethesentencesbelow.Chooseyouranswersfromthelistofwords.Youcanonlyuseeachwordonce.

NBTherearemorewordsinthelistthanspacessoyouwillnotusethemall.

Inthefirstclinicaltrials,scientistswilltryto……10……adenovirusandvaccinia,soboththeviruseswillbelesspathogenicthanthe……11…….Theseuncoatedviruseswillbeapplieddirectlytocertainareastoconfirmsafetyonhumanbeingsandtheright……12……needed.Theexperimentswillfirstlybe……13……tothetreatmentofcertaincancers

我国海关机关规定,进口货物的收货人自运输工具申报进境之日起,超过()时间未向海关申报的,其进口货物由海关提取依法变卖处理。

A、1个月
B、3个月
C、6个月
D、1年

Theorderissourgentlyrequiredthatwemustaskyoutomaketheearliestpossibleshipment.

Inmostcitiesandtowns,thehighvolumesofroadtrafficbecomeaproblem.Whatarethecausesofthatandwhatactionscouldbetakentosolvetheproblem?

Arecompaniesprovidingtheseservicestolookgoodtothecommunityorbecausetheyarefinanciallysuccessful?

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