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1、http://bailiedu.com托福阅读TPO1题目解析TPO是托福备考圣经，但是并不是有“圣经”就能完全把握托福考试。还要看大家怎么去利用这份资料。针对原文，我们可以最大限度的剖析再剖析。直到把文章掌握得滚瓜烂熟。而大家又是怎样对待其中的每个考题呢？是做完对对答案，记下答对率；还是认真分析每个考题在考什么，找出托福阅读的“点”在哪？前者居多吧！所以关于托福阅读TPO，小编希望最大限度地利用这些ETS提供的阅读题目。在题目中，找到每个题目考察点，给出最全最有逻辑的解析。今天，小编分享给大家的是关于TPO1Timber
2、lineVegetationonMountains的题目分析。TimberlineVegetationonMountains山上树带界线的植被1.Thetransitionfromforesttotreelesstundraonamountainslopeisoftenadramaticone.Withinaverticaldistanceofjustafewtensofmeters,treesdisappearasalife-formandarereplacedbylowshrubs,herbs,andgrasses.T
3、hisrapidzoneoftransitioniscalledtheuppertimberlineortreeline.Inmanysemiaridareasthereisalsoalowertimberlinewheretheforestpassesintosteppeordesertatitsloweredge,usuallybecauseofalackofmoisture.2.Theuppertimberline,likethesnowline,ishighestinthetropicsandlowestinthe
4、PolarRegions.ItrangesfromsealevelinthePolarRegionsto4,500metersinthedrysubtropicsand3,500-4,500metersinthemoisttropics.Timberlinetreesarenormallyevergreens,suggestingthatthesehavesomeadvantageoverdeciduoustrees(thosethatlosetheirleaves)intheextremeenvironmentsofth
5、euppertimberline.Therearesomeareas,however,wherebroadleafdeciduoustreesformthetimberline.Speciesofbirch,forexample,mayoccuratthetimberlineinpartsoftheHimalayas.3.Attheuppertimberlinethetreesbegintobecometwistedanddeformed.Thisisparticularlytruefortreesinthemiddlea
6、ndupperlatitudes,whichtendtoattaingreaterheightsonridges,whereasinthetropicsthetreesreachtheirgreaterheightsinthevalleys.Thisisbecausemiddle-andupper-latitudetimberlinesarestronglyinfluencedhttp://bailiedu.combythedurationanddepthofthesnowcover.Asthesnowisdeeperan
7、dlastslongerinthevalleys,treestendtoattaingreaterheightsontheridges,eventhoughtheyaremoreexposedtohigh-velocitywindsandpoor,thinsoilsthere.Inthetropics,thevalleysappeartobemorefavorablebecausetheyarelesspronetodryout,theyhavelessfrost,andtheyhavedeepersoils.4.Ther
8、eisstillnouniversallyagreed-onexplanationforwhythereshouldbesuchadramaticcessationoftreegrowthattheuppertimberline.Variousenvironmentalfactorsmayplayaro
