【托福聽力備考】tpo13 聽力文本——lecture 4

1、【托福聽力備考】TPO13聽力文本——Lecture4眾所周知，托福TPO材料是備考托福聽力最好的材料。相信眾多備考托福的同學(xué)也一直在練習(xí)這套材料，那么在以下內(nèi)容中我們就為大家?guī)硗懈PO聽力練習(xí)的文本，希望能為大家的備考帶來幫助。TPO13Lecture4AstronomyNarrat:Listentopartofalectureinanastronomyclass.Profess:OKIwannagooverthedifferen

2、ttypesofmeteiteswhatwe’velearnedfromthemaboutthefmationofEarththesolarsystem.Uh…thethingiswhat’sespeciallyinterestingaboutmeteitesisthattheycomefrominterplaaryspacebuttheyconsistofthesamechemicalelementsthatareinmatterig

3、inatingonEarthjustindifferentproptions.Butthatmakesiteasiertoidentifysomethingasameteiteasopposedto…tojustaterrestrialrock.Sototalkaboutwheremeteitescomefromweneedtotalkaboutcometsasteroidswhichbasically...they’rebasical

4、lymadeupofdebrisleftoverfromtheiginofthesolarsystem4.6billionyearsago.NowI’mgoingabitoutofaderhere…um…I’mnotgoingtogointoanydepthoncometsasteroidsnowbutwe’llcomebacklaterdothat.FnowI’lljustcoversomebasicinfoaboutthem.OKc

5、ometsasteroids.Itmighthelpifyouthinkof...rememberwetalkedaboutthetwoclassesofplasinoursolarsystemhowtheydifferactuallymakeitthrough.Nowwe’vebeenfindingmeteitesonEarthfthoussofyearswe’veanalyzedenoughofthemtolearnalotabou

6、ttheircompositionmostcomefromasteroidsthoughafewmayhavecomefromcomets.Soessentiallytheyarerockslikerocksthey’remixturesofminerals.Theyaregenerallyclassifiedintothreebroadcategiesstonesstonyironsirons.Stonemeteiteswhichwe

7、refertosimplyasuhstonesarealmostentirelyrockmaterial.Theyactuallyaccountfalmostallofthemeteitematerialthatfallstoearth.Butevensoit’sraretoeverfindone.Imeanit’seasiertofindanironmeteiteastonyiron.AnyoneguesswhyLookattheir

8、names.WhatdoyouthinkironmeteitesconsistofStudent:MostlyironProfess:Yeah…ironsomenickelbothofwhicharemetals.ifyou’retryingtofindmetalStudent:Oh!Metaldetects!Profess:Rightthankyou.Atleastthat’spartofit.Stonemeteitesiftheyl

9、iearoundexposedtotheweatherfafewyearswellthey’remadeofrocksotheyenduplookingalmostindistinguishablefromcommonterrestrialrocksonesthatiginatedonearth.Soit’shardtospotthembyeye.Butwecanusemetaldetectstohelpusfindtheotherst