老托福阅读0308-豆柴文库

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0308托福试题

阅读（55minutes）
Question1-11

Iffoodisallowedtostandforsometime,itputrefies.Whentheputrefiedmaterial
isexaminedmicroscopically,itisfoundtobeteemingwithbacteria.Wheredothese
bacteriacomefrom,sincetheyarenotseeninfreshfood?Evenuntilthemid-nineteenth
century,manypeoplebelievedthatsuchmicroorganismsoriginatedbyspontaneous
(5)generation,ahypotheticalprocessbywhichlivingorganismsdevelopfromnonliving
matter.
ThemostpowerfulopponentofthetheoryofspontaneousgenerationwastheFrenchchemistandmicrobiologistLouisPasteur(1822-1895).Pasteurshowedthatstructures
presentinaircloselyresemblethemicroorganismsseeninputrefyingmaterials.Hedid
(10)thisbypassingairthroughguncottonfilters,thefibersofwhichstopsolidparticles.After
theguncottonwasdissolvedinamixtureofalcoholandether,theparticlesthatithad
trappedfelltothebottomoftheliquidandwereexaminedonamicroscopeslide.Pasteur
foundthatinordinaryairtheseexistsavarietyofsolidstructuresranginginsizefrom
0.01mmtomorethan1.0mm.Manyofthesebodiesresembledthereproductive
(15)structuresofcommonmolds,single-celledanimals,andvariousothermicrobialcells.
Asmanyas20to30ofthemwerefoundinfifteenlitersofordinaryair,andtheycould
notbedistinguishedfromtheorganismsfoundinmuchlargernumbersinputrefyingmaterials.Pasteurconcludedthattheorganismsfoundinputrefyingmaterialsoriginated
fromtheorganizedbodiespresentintheair.Hepostulatedthatthesebodiesareconstantly
(20)beingdepositedonallobjects.
Pasteurshowedthatifanutrientsolutionwassealedinaglassflaskandheatedto
boilingtodestroyallthelivingorganismscontaminatingit,itneverputrefied.Theproponentsofspontaneousgenerationdeclaredthatfreshairwasnecessaryfor
spontaneousgenerationandthattheairinsidethesealedflaskwasaffectedinsomeway
(25)byheatingsothatitwouldnolongersupportspontaneousgeneration.Pasteurconstructedaswan-neckedflaskinwhichputrefyingmaterialscouldheheatedtoboiling,butair
couldreenter.Thebendsintheneckpreventedmicroorganismsfromgettingintheflask..Materialsterilizedinsuchaflaskdidnotputrefy.

1,Whatdoesthepassa