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。

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

简介：TheMiddleEasthasbeenahotspotininternationalpoliticssincethemid-20thcenturyowingtoitsspecialgeostrategicpositionanditsabundantresourcesofoilandnaturalgas.Thesecontributeshavemadeitanareaofcontentionforanystatewithaglobaloverview.DuringtheColdWar,thesharpdifferencesbetweentwosuperpowers,theU.S.andtheSovietUnion,couldhavebroughtthesituationtothebrinkofathirdworldwar.AftertheColdWar,theU.S.becamethedominantpowerintheMiddleEast.TheU.S.containedtherecalcitrantregimeofSaddamHusseininIraqandanIranengagedinIslamicrevolution.Italsolaunchedandpropelled,thoughinvain,theMiddleEastpeaceprocess.After9.11,underthebannerofantiterrorism,theU.SwagedapreemptivewaragainstIraq,overthrewtheSaddamregime,andimplementedintheMiddleEastastrategyof'democratictransformation'.Fromthatpoint,theMiddleEastenteredaneraofconfusion.

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简介：Thestrategiclegacyof9/11willoutlivetheKoreanandVietnamWarsandthetwoGulfWarsbecausetheytriggeredonlyquantitativeratherthanqualitativetransformationsintheinternationalstrategiclandscape.The9/11disastersparkedtheAfghanandIraqWarsandtheglobal'waronterror,'whichasyethavenoendinsight.Ithasalreadyledtoaqualitativeoverhaulintheworldstrategicorder,affectingtheinternationalpowerbalanceandperspectivesoninternationalrelationssomuchthateventheunfoldingupheavalinWestAsiaandtheNorthAfricaknownastheArabSpringseemsminorby

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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：说到since,我们最熟悉的用法或许就是＂since前面要用现在完成时态＂,其实,since还有其他不同的用法,这些用法容易被大家忽略。本期笔者就来系统梳理since的用法,定会让大家开阔眼界。Since用法的思路体系下面笔者从两个角度来考察since的用法：一是since后面的结构特点;而是since前面的修饰对象特点（这是本期内容的重点）。

简介：一、“Itwas＋具体的时间点＋when…”表示“当某事发生时，是几点钟或哪一年”。此句是由when引导的时间状语从句，而不是由when引导的定语从句。

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.

简介：Affectedbyeconomyrecessionstartedsince2008,globalconsumptionbecameweak.Chineserareearthindustry,whichhashighdependenceontheconsumptionfromoutsideChina,experiencedatoughperiodoftimeledbyanabruptdecreaseindemand.Pricesofrareearthproductsdroppedrapidlyandsignificantlyandfluctuatedatalowlevelnearthecostlinepersistently.Themarketwasverygrimin2009.Atthebeginningof2009,Chinesegovernmentsetdowntenindustryrevitalizationanddevelopmentpro-

简介：Generally,inregardofproduction,lanthanumandceriumaccountfor70.57%,neodymiumandpraseodymium,necessaryforNdFeBindustry,20.08%,terbiumanddysprosium0.82%,yttriumoxide4.59%andotherproducts3.94%.Intermsoflightrareearthandheavyrareearth,proportionoflightrareearthincludinglanthanum,cerium,praseodymium,neodymium,samarium,europiumandgadoliniumrepresents93.72%,andheavyrareearthincludingterbium,dysprosium,holmium,thulium,erbium,ytterbiumlutetiumandyttrium6.28%.

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