简介：since一词在高考中出现率很高，现将其用法归纳如下，以帮助同学们较全面地了解和运用该词。

简介：在中学英语教材里，since是一个经常出现的词。它既可以作介词和副词，还可以作从属连词。现将其用法归纳如下，供大家参考。

简介：since作为时间连词表示“自从……以来”，我相信很多读者都知道其用法——since后边所接从句的谓语要用“一般过去时态”，与其搭配的主句谓语则用“现在完成时态”，比如：

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简介：since是一出现率较高的单词，它可用作介词、副词或连词。现将与时间有关的since的用法分述如下。

简介：Duetothecloserelationshipbetweenregionalclimateanomaliesandsocial-economyandsocietydevelopment,climatologistsworldwidepaidgreatattentiontotheregionalclimateanomaliesoveralongperiodoftimeandthecorrespondinginvestigationofregionalclimatemodelinghasmadegreatprogresses.Since1990theregionalclimatesimulationshavemadeamoresubstantialachievement.Thispaperwillfocusonthereliabilityanduncertaintiesofregionalclimatemodelingbyglobalclimatemodels,theadvancesonregionalclimatemodelingintheworldandtheoutlookofregionalclimatemodeling.

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简介：这一组词都含有“由于、因为”的意思，但用法不同。本文就其不同用法归纳分述如下，供同学们学习参阅。

简介：Since用以表示时间,它的意义是“fromsomespecificpointoftimeinthepastuptoandincludingthepresentmoment”它把过去的某一活动或情景与现在联系在一起。分以下几种情况讲述:1.Since作为介词,其模式为:

简介：Urbangreening,urbanforestryandurbangreenstructureplanningalllookatacityasaunitandintendtoimprovethestatusofgreenspaceinthecity.Eventhoughtheyarenewterms,theirconceptshaveevolvedoveraratherlongperiod.Thispaperpresentsahistoricalreviewofwesternconceptsforurbangreeningsincethe1850s.Thefirstaimistoestablishanoverviewofhowtheurbangreeningconcepthasdevelopedandwhattherelationshipsarebetweenthehistoricalconceptsandurbangreening,urbanforestryandurbangreenstructureplanningtoday.Thesecondarypurposeistounderstandsomekeyissuesforurbangreeningthroughtheexaminationofhistoricalprecedents.Basedonaliteraturereview,thepaperpresentsseveralhistoricalconceptsforurbangreening-rampartareaplanning,parksystem,greenbelts,greenwedgesandgreenways.Thenewconceptofurbangreenstructureisalsointroduced.Eachconceptisdefined.Thesocialbackgroundandtheinfluenceoncitydevelopmentaredescribed.Thereviewshowsthattheconceptofurbangreeninghasalonghistory,parallelwiththedevelopmentofthecityplanningconcepts.Thescopeofurbangreeninghasbecomelargeroverthepastyears.Thefunctionsofurbangreenspacehavechangedfromsingle-purposetomulti-purpose.Thestudyindicatesthathistoricalconceptsmaystillgiveinspirationintoday'surbangreeningprocess.

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简介：虽然since引导的时间状语从句总是以肯定形式出现，但它表达的含义却可能是肯定的，也可能是否定的。现将其规律归纳如下。

简介：Abetterunderstandingofthelong-termglobalcarboncyclerequiredestimateofthechangesinterrestrialcarbonstorageafterthelastglacialperiod.Theresultsofsimulationatmid-Holocene(MH)fromPMIP(PaleoclimateModelingIntercomparisonProject)andthemoderndatafromCRU(ClimateResearchUnit,EastAngliaUniversity,UK)allowustousetheAtmosphere-VegetationInteractionModel(AVIM)tosimulatetheChineseterrestrialnetprimaryproductivity(NPP)at6kaBPandpresenttime.ThechangeofNPPandtotalNPPinChinafromnowtomid-Holoceneareabout54gm-2yr-1and0.63Pgyr-1,respectively,mainlyduetothebuild-upoftemperateforestandtropicalrainforest.ChineseterrestrialNPPvariationfromMHtonowiscloselyrelatedtothevariationinintensityofAsianmonsoon,whichcontrolledtheclimate-vegetationpatternchange.

简介：ThisarticleaddressessedimentresearchcarriedoutfortheThreeGorgesProjectsince1993,whentheconstructionoftheprojectwasformallystarted.Emphasisoftheresearchhasbeenplacedonthesolutionofrelevantproblemsarisingfromdesignandconstructionofvariousstructures,includingsedimentationproblemsintheChongqingreach;layoutoftheupperlockapproachchannelandwaysandmeanstomitigateitsdeposition;increasingreservoircapacitybyoptimizingreservoiroperation;compensatingdepthofflowrequiredbynavigationbelowtheGezhoubaProjectcausedbyscouring;mitigationofadverseeffectsoferosiononthereachfromZhichengtoJiangkou;andevaluatingscouroftheJinjiangreachcausedbyreleasingflowsoflowconcentrationsfromtheTGP.Inaddition,reductionofthesedimentloadenteringintothereservoirareaoftheTGPintherecentyearsaswellasthatexpectedoftheprojectedconstructionoflargehydropowerstationsontheJinshaRiverupstreamoftheTGPreservoirisalsonotedanddiscussed.

简介：AbstractIreflectuponthedevelopmentofnonlineartimeseriesanalysissince1990byfocusingonfivemajorareasofdevelopment.Theseareasincludetheinterfacebetweennonlineartimeseriesanalysisandchaos,thenonparametric/semiparametricapproach,nonlinearstatespacemodelling,financialtimeseriesandnonlinearmodellingofpanelsoftimeseries.

简介：Theeffectiveprecipitationandtheframeofatmosphericcirculationinthepastthreekeyperiods,i.e.30kaBP,18kaBPand6kaBP,havebeenanalyzedonthebasisofthepalaeolakestatusrecordproducedbytheChineseLakeStatusDataBase.Theresultsshowthatthewest-centralpartofChinawascharacterizedbyhighlake-levelsat30kaBP,resultingfromstrengthenedsouthwestmonsoons;whereasthehighlakestand,occurringinthewest-centralpartofChinaat18kaBP,wascausedbythesouthwardshiftandthestrengtheningofwesterliesalthoughthehigh-standdistributionwasreduced.Meanwhile,theeast-centralpartofChinawasunderthecontrolofstrongwintermonsoonsat18kaBP.Thehighlake-levels,whichoccurredintheeast-centralpartofChinaat6kaBP,arerelatedtotheenhancedEast-Asiansummermonsoons;whiletheloweringofthelake-levelinthewest-centralpartofChinaat6kaBPwasduetothenorthwardshiftandcorrespondingshrinkofthewesterlies.Acomparisonb

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简介：TheCaofeidiansandbar-lagoonsystemissituatedalongthenorthwestcoastoftheBohaiSea.Thesystemhasevolvedfromtheabandoneddelta,whichcameintobeingbySuheRiverandXiaoqingheRiverinthemiddleHolocene.Atthemoment,thesystemhasalmostlostthesupplyofriversediments.(Fig.1)