托福阅读TPO18(试题+答案+译文)第3篇-Lightning.docx

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1、托福浏览TPO18(试题+答案+译文)第3篇:Lightning托福浏览TPO18(试题+答案+译文)第3篇:LightningTPO是我们常用的托福模考工具，对我们的备考很有价值，下面我给大家带来托福浏览TPO18(试题+答案+译文)第3篇:Lightning。托福浏览原文【1】Lightningisabrilliantflashoflightproducedbyanelectricaldischargefromastormcloud.Theelectricaldischargetakesplacewhentheattractivetensionbetweenaregionofnegativ

2、elychargedparticlesandaregionofpositivelychargedparticlesbecomessogreatthatthechargedparticlessuddenlyrushtogether.Thecomingtogetheroftheoppositelychargedparticlesneutralizestheelectricaltensionandreleasesatremendousamountofenergy,whichweseeaslightning.Theseparationofpositivelyandnegativelychargedpa

3、rticlestakesplaceduringthedevelopmentofthestormcloud.【2】Theseparationofchargedparticlesthatformsinastormcloudhasasandwich-likestructure.Concentrationsofpositivelychargedparticlesdevelopatthetopandbottomofthecloud,butthemiddleregionbecomesnegativelycharged.Recentmeasurementsmadeinthefieldtogetherwith

4、laboratorysimulationsofferapromisingexplanationofhowthisstructureofchargedparticlesforms.Whathappensisthatsmall(millimeter-tocentimeter-size)pelletsoficeforminthecoldupperregionsofthecloud.Whentheseicepelletsfall,someofthemstrikemuchsmallericecrystalsinthecenterofthecloud.Thetemperatureatthecenterof

5、thecloudisabout-15orlower.Atsuchtemperatures,thecollisionbetweentheicepelletsandtheicecrystalscauseselectricalchargestoshiftsothattheicepelletsacquireanegativechargeandtheicecrystalsbecomepositivelycharged.Thenupdraftwindcurrentscarrythelight,positivelychargedicecrystalsuptothetopofthecloud.Theheavi

6、ernegativelychargedicepelletsarelefttoconcentrateinthecenter.Thisprocessexplainswhythetopofthecloudbecomespositivelycharged,whilethecenterbecomesnegativelycharged.Thenegativelychargedregionislarge:severalhundredmetersthickandseveralkilometersindiameter.Belowthislarge,cold,negativelychargedregion,the

7、cloudiswarmerthan-15,andatthesetemperatures,collisionsbetweenicecrystalsandfallingicepelletsproducepositivelychargedicepelletsthatthenpopulateasmallregionatthebaseofthecloud.【3】Mostlightningtakesplacewithinacloudwhenthechargeseparationwithinthecloudcollapses.However,asthestormclouddevelops,theground

8、beneaththecloudbecomespositivelychargedandlightningcantakeplaceintheformofanelectricaldischargebetweenthenegativechargeofthecloudandthepositivelychargedground.Lightningthatstrikesthegroundisthemostlikelytobedestructive,soeventhoughitrepresentsonly20percentofalllightning,ithasreceivedalotofscientific

9、attention.【4】Usinghigh-speedphotography,scientistshavedeterminedthattherearetwostepstotheoccurrenceoflightningfromacloudtotheground.First,achannel,orpath,isformedthatconnectsthecloudandtheground.Thenastrongcurrentofelectronsfollowsthatpathfromthecloudtotheground,anditisthatcurrentthatilluminatesthec

10、hannelasthelightningwesee.【5】Theformationofthechannelisinitiatedwhenelectronssurgefromthecloudbasetowardtheground.Whenastreamofthesenegativelychargedelectronscomeswithin100metersofthegrounditismetbyastreamofpositivelychargedparticlesthatcomesupfromtheground.Whenthenegativelyandpositivelychargedstrea

11、msmeet,acompletechannelconnectingthecloudandthegroundisformed.Thechannelisonlyafewcentimetersindiameter,butthatiswideenoughforelectronstofollowthechanneltothegroundinthevisibleformofaflashoflightning.Thestreamofpositiveparticlesthatmeetsthesurgeofelectronsfromthecloudoftenarisesfromatallpointedstruc

12、turesuchasametalflagpoleoratower.Thatiswhythesubsequentlightningthatfollowsthecompletedchanneloftenstrikesatallstructure.【6】Onceachannelhasbeenformed,itisusuallyusedbyseverallightningdischarges,eachofthemconsistingofastreamofelectronsfromthecloudmeetingastreamofpositiveparticlesalongtheestablishedpa

13、th.Sometimes,however,astreamofelectronsfollowinganestablishedchannelismetbyapositivestreammakinganewpathupfromtheground.Theresultisaforkedlightningthatstrikesthegroundintwoplaces.托福浏览试题1.Accordingtoparagraph1,allofthefollowingtakeplaceinthedevelopmentofaflashoflighteningEXCEPTA.greattensionbetweentw

14、ooppositelychargedregions.B.anincreaseinnegativelychargedparticlesoverpositivelychargedparticles.C.oppositelychargedparticlescomingtogether.D.thereleaseofelectricalenergyintheformofvisiblelight.2.Theword“tremendousinpassage1isclosestinmeaningtoA.distinct.B.growing.C.huge.D.immediate.3.Accordingtopar

15、agraph2,whatcausesicecrystaltobecomepositivelycharged?A.Collisionswithicepellets.B.Collisionswithnegativelychargedicecrystalsatthebaseofthecloud.C.Becomingconcentratedinthecentralregionofthecloud.D.Formingatatemperaturegreaterthan-15.4.Theword“acquireinpassage2isclosestinmeaningtoA.reject.B.obtain.C

16、.need.D.produce.5.Accordingtoparagraph2,whyarepositivelychargedicepelletsproducedinthelowerpartofthecloud?A.Collisionsbetweenicecrystalsandicepelletsincreaseinnumberinthelowerpartofthecloud.B.Thelowerpartofthecloudissmallerthantheregionaboveit.C.Moreicepelletsthanicecrystalsreachthelowerpartoftheclo

17、ud.D.Temperatureinthelowerpartofthecloudarewarmerthan-15.6.Accordingtoparagraph2,themiddleregionofacloudbecomesnegativelychargedduetoallofthefollowingEXCEPTA.ashiftofelectricalchargedbetweenicepelletsandicecrystals.B.negativelychargedicepelletsthatremaininthemiddle.C.atemperatureof-15orless.D.thedev

18、elopmentofapositivechargeatthebaseofthecloud.7.Itcanbeinferredfromparagraph2thatpartofthereasonthatthetopofastormcloudbecomespositivelychargedisthatA.thetopofthecloudiswarmerthanthemiddleofthecloud.B.themiddleofthecloudisalreadyoccupiedbypositivelychargedparticles.C.thenegativelychargedicepelletsare

19、tooheavytobecarriedbytheupdraftsthatmoveicecrystals.D.collisionsbetweenicepelletsinthetopofthecloudproducemainlypositivelychargedparticles.8.Theauthorremarksthat(inparagraph3)“LightningthatstrikesthegroundisthemostlikelytobedestructiveinordertoexplainwhyA.thisformoflightninghasbeeninvestigatedsomuch

20、.B.thisformoflightningisnotascommonaslightningwithinacloud.C.scientificunderstandingofthisformoflightningisimportant.D.thebuildupofpositivechargeonthegroundbeneathastormcloudcanhaveseriousconsequences.9.Theword“illuminatesinpassage4isclosetinmeaningtoA.opens.Bpletes.C.lights.D.electrifies.10.Accordi

21、ngtoparagraph5,whichofthefollowingistrueofthestreamofchargedparticlesfromtheground?A.Itpreventsstreamsofelectronsfromthecloudfromstrikingtheground.B.Itcompletesachannelthatconnectsthestormcloudwiththeground.C.Itproducesastreamofelectronsfromthecloud.D.Itwidensthepathmadebytheinitialstreamofelectrons

22、fromthecloud.11.Whichofthefollowingclaimsaboutlightningstrikescanbeinferredfromparagraph5?A.Duringalightningstrikethediameterofthechanneltheelectronsfollowisconsiderablyenlargedbeyondafewcentimeters.B.Abuildingisunlikelytobehitbylightningunlessitisatleast100meterstall.C.Abuildingishitbyalightningstr

23、ikebecausethebuildingitselfhasfirstdeterminedthepaththelighteningthentakestoit.D.Thelightofalightningstrikefirstappearsatthepointwherethestreamsofnegativeandpositiveparticlesmeet.12.Theword“initiatedinparagraph5isclosetinmeaningtoA.started.B.intensified.C.finished.D.expected.13.Lookatthefoursquarest

24、hatindicatewherethefollowingsentencecouldbeaddedtothepassage.Wherewouldthesentencebestfit?Thedescendingstreamofelectronsdividesatthepointwherethenewpositive-streamchannelintersectstheestablishedpath.Theformationofthechannelisinitiatedwhenelectronssurgefromthecloudbasetowardtheground.Whenastreamofthe

25、senegativelychargedelectronscomeswithin100metersofthegrounditismetbyastreamofpositivelychargedparticlesthatcomesupfromtheground.Whenthenegativelyandpositivelychargedstreamsmeet,acompletechannelconnectingthecloudandthegroundisformed.Thechannelisonlyafewcentimetersindiameter,butthatiswideenoughforelec

26、tronstofollowthechanneltothegroundinthevisibleformofaflashoflightning.Thestreamofpositiveparticlesthatmeetsthesurgeofelectronsfromthecloudoftenarisesfromatallpointedstructuresuchasametalflagpoleoratower.Thatiswhythesubsequentlightningthatfollowsthecompletedchanneloftenstrikesatallstructure.【A】Onceac

27、hannelhasbeenformed,itisusuallyusedbyseverallightningdischarges,eachofthemconsistingofastreamofelectronsfromthecloudmeetingastreamofpositiveparticlesalongtheestablishedpath.【B】Sometimes,however,astreamofelectronsfollowinganestablishedchannelismetbyapositivestreammakinganewpathupfromtheground.【C】Ther

28、esultisaforkedlightningthatstrikesthegroundintwoplaces.【D】14.Directions:Anintroductorysentenceforabriefsummaryofthepassageisprovidedbelow.CompletethesummarybyselectingtheTHERRanswerchoicesthatexpressthemostimportantideasinthepassage.Somesentencesdonotbelonginthesummarybecausetheyexpressideasthataren

29、otpresentedinthepassageorareminorideasinthepassage.Thisquestionisworth2points.Lightningtakesplacewhenaseparationofapositiveandnegativeelectricalparticlesthatdevelopsinastormcouldsuddenlycollapses.A.Astormcloudfirstdevelopsapositivelychargedlayeratthetop,thenanegativelychargedmiddlelayer,andfinally,a

30、positivelychargedlayeratthebottom.B.Aseparationofoppositelychargedparticlesincloudsdevelopsfromcollisionsoffallingicepelletswithicecrystals,fromupdrafts,andfromtemperaturevariations.C.Lightningfromcloudtogroundfollowsachannelthatformswhenastreamofelectronsmovingdownmeetsastreamofpositiveparticlescom

31、ingupfromtheground.D.Fieldstudies,laboratorysimulations,andhigh-speedphotographyhaveallbeenusedtoinvestigatethewaychargeseparationsdevelopinclouds.E.Lightningfromacloudtothegroundismorelikelytobedestructivethanislightningthattakesplacewithinacloud.F.Onceachannelhasbeenformed,itisusuallyusedbyseveral

32、successiveelectricaldischargesthatilluminatethechannelasflashesoflightning.托福浏览答案1.EXCEPT题，排除法，A的tension和做关键词定位至第二句，正确，不选;B的negatively和positivelychargedparticles同样定位至第二句，但原文没有比拟，所以B没讲，选;C的cometogether和D的release做关键词定位都至倒数第二句，都正确，都不选。2.tremendous大量的，宏大的，所以正确答案是huge。原句讲当带相反电荷的例子碰到一起的时候发生中和并释放什么样的能量，就是我

33、们能看到的闪电，大家都知道闪电的能量很大，所以选huge，C。A不同B增大D立即都不靠谱。3.以icecrystal和positivelycharged做关键词定位至第七句，讲在这样的温度下，icepellet和icecrystal的碰撞转移了电荷，使得pellet带负电，crystal带正电，所以答案应该是A碰撞;B固然也讲到碰撞，但不是和负电碰撞;D的温度不是带正电的决定条件。4.acquire获得，所以答案obtain正确，正如上题，原句讲icepellet和icecrystal的碰撞转移了电荷，使得pellet怎么样负电，crystal带正电，至少猜出acquire应该和become差

34、不多，是个从无到有的经过，答案是B。需要不一定有，C错;A拒绝与原文相反;D错，电荷不能产生。5.以positivelychargedicepellets做关键词定位至最后一句，讲在这个很大的，带负电的区域之下，碰撞产生了positivelychargedpellets，所以答案是D。A的increaseinnumber，B的smaller和C的比拟原文都没讲。6.EXCEPT题，排除法，A的icepelletsandicecrystals做关键词定位至第七句，正确，不选;B的inthemiddle做关键词定位至倒数第四句，正确，不选;C的数字做关键词定位至第六句，正确，不选;D的thebas

35、eofthecloud做关键词定位都至最后一句，但倒数第三句已经讲过thisprocessexplains，也就是讲原因到倒数第三句就给完了，D不是原因，错，选。7.修辞目的题，修辞点所在句子讲这种闪电具有毁坏性，所以尽管这类闪电只占全部的20%，它仍然遭到了很多关注，也就是解释下受关注是由于具有毁坏性，所以答案是A。8.illuminate发光，照射，所以C的light是正确答案。原句讲一股强烈的电子流沿通路从云层到地面，并且怎么样了那个通路，成为我们所看到的闪电，假如不照亮怎么看到闪电呢?所以C正确;A打开B完成D使带电都不能解释看见，所以都不对。9.以streamofchargedpar

36、ticlesfromtheground做关键词定位至第二句，讲来自地面的带负电的电子流会在地面以上100米左右碰上来自云层的带正电的电子流，然后又讲当二者碰在一起的时候就构成了通路，所以B构成通路是正确的。A的prevent，C的produce和D的widen原文都没讲。10.因而题关键词比拟难找，所以用排除法。A的diameterofthechannel和centimeter做关键词定位至第四句，但原文没有信息能推出widen，所以A错;B的数字做关键词定位至第二句，讲100米内正负电荷就会碰到，所以B讲反;C的path做关键词定位至最后一句的channel，讲正电荷通常升起自地面上的一个高

37、点，比方旗杆，然后闪电由通路到达地面，也就是讲旗杆等高的建筑物是这个channel的一部分，所以C讲building决定了path是对的，选C;D的firstappear原文没有相关信息。11.以topofthestormcloud做关键词定位至倒数第五句，讲向上的气流将轻的，带正电的粒子带到云层上部，这自然是上部云层带正电的原因，反过来讲也就是带负电的粒子很重，所以没有上来，所以答案是C。原文只是讲了中部和下部的温度，上部温度没有信息，所以A错;由倒数第四句可知中部是负电，B讲反了;D原文也没讲。12.initiate开场，所以正确答案是A。原文讲通路构成怎么了，当云层底部的电子向地面运动的

38、时候，接着又讲这些云层中的粒子和地面上来的粒子碰到一起之后，闪电的通路就完全构成了，也就是上文的云层底部的电子下来是构成的开场，所以答案是start，C结束讲反了;B加强和D期望完全不靠谱。13.两个过渡点，名词establishedpath和动词divide，根据establishedpath能够确定答案是A/B/C，注意原文中establishedchannel和establishedpath是同义词，所以不要忘了C答案，根据divide与最后一句forked的同义替换确定C或者D，所以C是答案。14.Astorm选项明显不对，由于正负电荷是同时构成的，没有先后，A不选。Lightning

39、fromcloudtoground选项对应原文第五段的第一句和第三句，C正确。Lightningfromacloudtotheground选项MS对应第三段最后一句，但原文没有比拟，E不选。Aseparation选项对应原文第二段，B正确。Field选项是原文第二段和第四段的细节，D不选。Once选项对应原文最后一段第一句，F正确。托福浏览译文【1】闪电是由雷雨云放电产生的一道亮堂夺目的闪光。当带正电荷粒子区域与带负电荷粒子区域之间的吸引力大到使带电粒子霎时碰撞到一起就会发生放电现象。相反的带电粒子的结合中和了电压并释放出宏大的能量，这就是我们看到的闪电。在雷雨云构成的经过中正负带电粒子互相分

40、离。【2】构成雷雨云的带电粒子的分离具有一种三明治构造。带正电的粒子聚集在云的顶部和底部，但是中间区域构成的是带负电的粒子。最近的野外测量以及实验室模拟为这种带电粒子的排列构造提供了可能的解释。实际上在此经过中在云层较冷的上部区域构成了细小的(毫米到厘米大小)冰丸。当这些冰丸飘落时，一部分会与云层中心比冰丸小得多的冰晶相撞。云层中心的温度大约在零下15摄氏度或者更低。在此温度下，冰丸和冰晶的撞击会使电荷发生转移，冰丸由此获得了负电而冰晶获得了正电。随后上升气流会将较轻的正电冰晶带到云的顶部。较重的负电冰丸会留在云层中部并积累起来。这个经过解释了为什么云的顶部带正电而中部带负电。带负电的区域非常

41、大：厚度达数百米，直径达几千米。位于这片又大又冷的带负电区域之下的云层的温度要高于零下15摄氏度，在此温度下，冰晶和降落的冰丸的碰撞会产生带正电荷的冰丸，于是在云层的底部聚集成一小片区域。【3】大部分的闪电发生在云层塌陷电荷分离的云层内部。但是，随着雷雨云的发展，云层下方的地面会带上正电，闪电就能够在带负电的云和带正电的陆地之间以放电的形式发生。击中地面的闪电是最有可能带有毁坏性的，所以即便它只占所有闪电的20%，还是遭到了很大的科学关注。【4】通过高速摄影，科学家已经确定从云层到地面发生闪电的经过有两步。首先，要建立连接云层和地面的通道或者途径。然后强电流会沿着这条通道从云层传向地面，这股照

42、亮通道的电流就是我们看到的闪电。【5】电子从云层基部涌向地面就会开场构成通道。当这些负电荷距离地面不到100米的时候，会碰到来自地面的带正电的粒子流。一旦正负带电粒子流相遇，一条连接云层和地面的完好的通道便构成了。这个通道直径仅有几厘米，但是已经足以使电子以一道闪电这种可见的形式通过通道到达地面。那些与从云层涌来的电子相遇的带正电的粒子流通常来自于高大的带尖顶的建筑物，例如金属旗杆或塔。这就是为什么接下来通过完好通道的闪电往往会击中高层建筑的原因。【6】一旦通道构成，同一条通道能够发生屡次闪电放电，每一次都是来自云层的电子流在已有通道上碰到带正电的粒子。但是有时候，通过已有通道的电子流会碰到从地面新途径来的带正电的电子流。结果就是构成在两处击中地面的叉状闪电。托福浏览TPO18(试题+答案+译文)第3篇:Lightning