托福閱讀長難句21天訓(xùn)練營Day

長難句解析21天訓(xùn)練營Day3Conversely,improvedencodingofwhattheyhearmayhelpthembetterunderstandandrememberstoriesandthusmakethestoriesmoreusefulforrememberingfutureevents.Missinguntilrecentlywerefossilsclearlyintermediate,ortransitional,betweenlandmammalsandcetaceans.Pakicetuswasfoundembeddedinrocksformedfromriverdepositsthatwere52millionyearsold.Theskulliscetacean‐likebutitsjawboneslacktheenlargedspacethatisfilledwithfatoroilandusedforreceivingunderwatersoundinmodernwhales.Severalskeletonsofanotherearlywhale,Basilosaurus,werefoundinsedimentsleftbytheTethysSeaandnowexposedintheSaharadesert.Theexpansionofdesertlikeconditionsintoareaswheretheydidnotpreviouslyexistiscalleddesertification.Insomecasestheloosesoilisblowncompletelyaway,leavingastonysurface.Desertificationisaccomplishedprimarilythroughthelossofstabilizingnaturalvegetationandthesubsequentacceleratederosionofthesoilbywindandwater.Theimpactofraindropsontheloosesoiltendstotransferfineclayparticlesintothetiniestsoilspaces,sealingthemandproducingasurfacethatallowsverylittlewaterpenetration.Thegradualdryingofthesoilcausedbyitsdiminishedabilitytoabsorbwaterresultsinthefurtherlossofvegetation,sothatacycleofprogressivesurfacedeteriorationisestablished.Insomeregions,theincreaseindesertareasisoccurringlargelyastheresultofatrendtowarddrierclimaticconditions.Theprocessmaybeacceleratedinsubsequentdecadesifglobalwarmingresultingfromairpollutionseriouslyincreases.Thesemiaridlandsborderingthedesertsexistinadelicateecologicalbalanceandarelimitedintheirpotentialtoadjusttoincreasedenvironmentalpressures.長難句解析21天訓(xùn)練營Day4Duringthedryperiodsthatarecommonphenomenaalongthedesertmargins,though,thepressureonthelandisoftenfarinexcessofitsdiminishedcapacity,anddesertificationresults.Sincetheraisingofmostcropsnecessitatesthepriorremovalofthenaturalvegetation,cropfailuresleaveextensivetractsoflanddevoidofaplantcoverandsusceptibletowindandwatererosion.Theconsequencesofanexcessivenumberoflivestockgrazinginanareaarethereductionofthevegetationcoverandthetramplingandpulverizationofthesoil.Theincreasedpressuresofexpandingpopulationshaveledtotheremovalofwoodyplantssothatmanycitiesandtownsaresurroundedbylargeareascompletelylackingintreesandshrubs.Theincreasinguseofdriedanimalwasteasasubstitutefuelhasalsohurtthesoilbecausethisvaluablesoilconditionerandsourceofplantnutrientsisnolongerbeingreturnedtotheland.Thewaterevaporatesandthesaltsareleftbehind,creatingawhitecrustallayerthatpreventsairandwaterfromreachingtheunderlyingsoil.Theextremeseriousnessofdesertificationresultsfromthevastareasoflandandthetremendousnumbersofpeopleaffected,aswellasfromthegreatdifficultyofreversingorevenslowingtheprocess.Inareaswhereconsiderablesoilstillremains,though,arigorouslyenforcedprogramoflandprotectionandcover‐cropplantingmaymakeitpossibletoreversethepresentdeteriorationofthesurface.Thecinemadidnotemergeasaformofmassconsumptionuntilitstechnologyevolvedfromtheinitial"peepshow"formattothepointwhereimageswereprojectedonascreeninadarkenedtheater.Forthepriceof25cents(or5centspermachine),customersmovedfrommachinetomachinetowatchfivedifferentfilms(or,inthecaseoffamousprizefights,successiveroundsofasinglefight).Inthephonographparlors,customerslistenedtorecordingsthroughindividualeartubes,movingfromonemachinetothenexttoheardifferentrecordedspee