tpo69三篇托福阅读TOEFL原文译文题目答案译文背景知识.docx

PAGE

PAGE1

tpo69三篇托福阅读TOEFL原文译文题目答案译文背景知识

TOC\o1-2\h\u4810阅读-1 2

13549原文 2

13243译文 5

1115题目 8

30030答案 15

23598背景知识 16

5078阅读-2 19

7090原文 19

23698译文 22

8650题目 25

18184答案 33

4938背景知识 34

27268阅读-3 41

8459原文 41

14406译文 45

13267题目 48

26721答案 55

21573背景知识 56

阅读-1

原文

WhySnakesHaveForkedTongues

①Theforkedtongueofsnakeshasintriguedpeopleformillennia,inspiringmanyhypotheses.Inmanyculturesandreligions,theforkedtonguesymbolizesmalevolenceanddeceit.ThefirstpersonknowntoinquireaboutthefunctionalsignificanceoftheforkedtonguewasAristotle;hesuggestedthatitwoulddoublethepleasureofsensationsoftaste.Bythebeginningofthetwentiethcentury,theconsensuswasthatthesnake’stongueisatactileorgan;thatis,thesnakeusesittotapthegroundmuchasablindpersonusesacane.

②In1920Browmansuggestedwhatseemedtobeawinninghypothesis:Whenthesnakeretractsitstongue,thetips(ortines)oftheforkedtongueareinsertedintoopeningsonbothsidesoftheroofofthemouth;throughtheseopeningschemicalstimulireachspecialorgansthathelpsnakesdetectsmells—thevomeronasalorgans(VNO).Theseorgansarehighlydevelopedinsnakes,lizards,andmanymammals.Theyareasecondsystemfordetectingsmellsthatappearstohaveevolvedspecificallytodetectpheromones,thechemicalsignalsthatanimalssecreteasmessagestootheranimalsoftheirspecies.Browmansuggestedthattheforkedtongueflicksout,pickingupchemicalsignals,andthendeliversthesetotheVNO.Thishypothesiswaswidelyacceptedintothe1980s.ThenX-raymoviestudiesoftongueflicksinsnakesandlizardswithforkedtonguesdisprovedthehypothesis;theyshowedthatwhenthetongueiswithdrawnintothemouth,itentersasheathandthetipsdonotgointotheopeningstotheVNO.Instead,thechemicalmoleculesaredepositedonpadsatthebottomofthemouth,and