历年托福考试阅读真题汇总含答案

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1、--WORD格式---可编辑---0308托福试题阅读（55minutes）Question1-11Iffoodisallowedtostandforsometime,itputrefies.Whentheputrefiedmaterialisexaminedmicroscopically,itisfoundtobeteemingwithbacteria.Wheredothesebacteriacomefrom,sincetheyarenotseeninfreshfood?Evenuntilthemid-nineteenthcen

2、tury,manypeoplebelievedthatsuchmicroorganismsoriginatedbyspontaneous(5)generation,ahypotheticalprocessbywhichlivingorganismsdevelopfromnonlivingmatter.ThemostpowerfulopponentofthetheoryofspontaneousgenerationwastheFrenchchemistandmicrobiologistLouisPasteur(1822-1895).

3、Pasteurshowedthatstructurespresentinaircloselyresemblethemicroorganismsseeninputrefyingmaterials.Hedid(10)thisbypassingairthroughguncottonfilters,thefibersofwhichstopsolidparticles.Aftertheguncottonwasdissolvedinamixtureofalcoholandether,theparticlesthatithadtrappedfe

4、lltothebottomoftheliquidandwereexaminedonamicroscopeslide.Pasteurfoundthatinordinaryairtheseexistsavarietyofsolidstructuresranginginsizefrom0.01mmtomorethan1.0mm.Manyofthesebodiesresembledthereproductive(15)structuresofcommonmolds,single-celledanimals,andvariousotherm

5、icrobialcells.Asmanyas20to30ofthemwerefoundinfifteenlitersofordinaryair,andtheycouldnotbedistinguishedfromtheorganismsfoundinmuchlargernumbersinputrefyingmaterials.Pasteurconcludedthattheorganismsfoundinputrefyingmaterialsoriginatedfromtheorganizedbodiespresentintheai

6、r.Hepostulatedthat--WORD格式--可编辑---精品资料分享----WORD格式---可编辑---1--WORD格式--可编辑---精品资料分享----WORD格式---可编辑---thesebodiesareconstantly(20)beingdepositedonallobjects.Pasteurshowedthatifanutrientsolutionwassealedinaglassflaskandheatedtoboilingtodestroyallthelivingorganismscontam

7、inatingit,itneverputrefied.Theproponentsofspontaneousgenerationdeclaredthatfreshairwasnecessaryforspontaneousgenerationandthattheairinsidethesealedflaskwasaffectedinsomeway(25)byheatingsothatitwouldnolongersupportspontaneousgeneration.Pasteurconstructedaswan-neckedfla

8、skinwhichputrefyingmaterialscouldheheatedtoboiling,butaircouldreenter.Thebendsintheneckpreventedmicroorganismsfromgettingint