Fromthetextwelearnthat__________.

问题：

阅读材料，回答下面的题目。
ThePublicHealthSystemOneofthebiggestchangessince1990isthedegreetowhichbioterrorismhasbecomeapublichealthpriority.Althoughtherehadlongbeenconcernaboutvulnerabilitytobiowarfareandbioterrorismtheanthraxepisodeinthefallof2001madeitclearthattheconcernisnolongertheoretical.Untilveryrecently,theimportantroleofpublichealthatthefrontlinesofbioterrorismpreparednesswasunrecognized.Althoughconcernaboutemerginginfectionshashelpedstimulatefundingforthechronicallyunder-appreciatedpublichealthsystem,thethreatofbioterrorismmotivatedthefirstrealinfusionofnewmoneyintopublichealthin
decades.
Manyofthecapabilitiesneededtodefendagainstbioterrorismarethesame:asthoseneededtocombatnaturalemerginginfections.Inbothinstance,theproblemisanunexpectedoutbreakofinfectiousdisease,ofwhichthefirstindicationislikelytobesickpeopleinemergencyroomsorclinics.Indeed,aswiththeanthraxattacks,thepublichealthandmedicalresponsesmaybeunderwaybeforethetruenatureoftheoutbreakisrecognized.Publichealthandtheinterfacewiththehealthcaresystemarethereforekeyelementsinanyeffectiveresponsetobioterrorism.
Whetherthebiggestthreatisnaturalorengineeredmuchremainstobedone.Effortstostrengthensurveillanceandresponseworldwideandtoimprovecommunicationmustbeacceleratedandsustained.Further,wehaveonlyscratchedthesurfaceintermsofunderstandingtheecologyofinfectiousdiseasesanddevelopingstrategiesforregulatingmicrobialtraffic.Weneedtoolsforbetterpredictiveepidemiologicmodelingwhenanewinfectionfirstappearsandforbetteranalysisofthefactorsthattransferpathogensacrossspecies.OneencouragingdevelopmentistheprogramintheecologyofinfectionsdiseasesthatwasstartedafewyearsagobetheNationalScienceFoundationincooperationwithNIH.
SARSisagoodyardstickofourprogressduringthepast13years.Thesyndromewasunusualbecausenovelinfectionsthatspreadfrompersontopersonarerelativelyrare.Oncecaseswerefinallyreported,thepublichealthresponsewasvigorous.WHOwarnedhealthcareproviders,researchersrapidlyidentifiedacandidatevirus,andprototypediagnostictestsquicklybecameavailable.ThevastreachoftheInternetwasinstrumentalinsharingformationandcoordinatingactivitiesworldwide.Despitetheseadvances,SARShadalreadyspreadtomanycountries.Infacthadthediseasebeenastransmissibleasinfluenza,itwouldhaveinvadedvirtuallyeverycountryintheworldbythetimethepublichealthresponsehadbegun.SowhatSARStellsusisthatalthoughwehavecomelongwaysince1990,westillhavealongwaytogo.
Themainideaexpressedinthefirstparagraphisthat__________.

A.bioterrorismisanengineeredthreattohumanbeings
B.bioterrorismcanbearrestedbyimprovingcommunication
C.naturalinfectionsandbioterrorismarethesameinessence
D.theanthraxattacksaremorethreateningthantheoutbreakofSARS

参考答案：A

参考解析：

【答案】A
【解析】从原文第三段第一句话：“Whetherthebiggestthreatisnaturalorengineered，muchremainstobedone”看出，bioterrorism是engineered，所以A对。B选项错在“canbearrested”上。原文是说能够减轻，但不能制止。C说自然的和恐怖主义性质的传染病是同一种性质的，显然不对，因为一个是natural，一个是engineered。D项同样不对。