Attheturnofthe 20thcentury, DutchphysicianChristiaanEijkmanshowedthatdiseasecanbecausednotonlybymicroorganismsbutbyadietaryefficiencyofcertainsubstancesnowcalledvitamins. In 1909 GermanbacteriologistPaulEhrlichintroducedtheworld'sfirstbactericide, achemicaldesignedtokillspecificlandsofbacteriawithkillingthepatient'scellsaswell.(1)____(2)____
Followingthediscoveryofpenicillinin 1928 byBritishbacteriologistSirAlexanderFleming, antibioticsjoinedmedicine'sChemicalarmorymakingthefightagainstbacterialinfectionalmostaroutinematter. Antibioticscannotactasviruses, butvaccineshavebeenusedtogreatlyeffecttopreventsomeofthedeadliestviraldiseases. Smallpox, onceaworldwidekiller, wascompletelyeradicatedbythelate 1970s,andintheUnitedStatesanumberofpoliocasesdroppedfrom 38,000 inthe 1950stolessthan 10 aye3r‘bythe 21stcentury.(3)____(4)____(5)____
Bythemiddleofthe 20thcenturyscientistsbelievedtheywerewellonthewaytotreating,preventing, oreradicatingmanyofthemostdeadlyinfectiousdiseasesthatplaguedhumankindforcenturies.(6)____ Andbythe 1980sthemedicalcommunity’sconfidenceinitsabilitytocontroltheinfectiousdiseasehadbeenshakenbytheemergencyofnewtypesofdisease-causingmicroorganisms.(7)____(8)____(9)____Newcasesoftuberculosisdeveloped, causedbybacteria;trainsthatwereresistanttoantibiotics. New, deadlyinfectionsonwhichtherewasnoknowncurealsoappeared, includingthevirusesthatcausehemorrhagicfeverandthehumanimmunodeficiencyvirus (HIV), thecauseofacquiredimmunodeficiencysyndrome.(10)____
专八改错训练附讲解100篇:Passage 54
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2016年04月05日 17:34:01