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：自从Holocene，在Xiliao河山谷的农业开垦从草地导致了一个巨大的风景变化到农田。在这份报纸，我们由自从Qing王朝，在史前，Liao-Jin王朝和时期分析三主要农业开垦在Xiliao河山谷重新考虑人陆地关系。我们主张当人口统计的压力出现在这个区域时，特别在最后开垦期间，intraregional迁居(第二迁居)是主要反应减轻如此的压力，它也区分二个不同解决地点：起始的区域和第二等的区域。由于这二个区域之间的环境差别，一个人引起了更多的严肃的骚乱到本地环境的后者上的耕作。因此，第二等的区域成为了严重需要环境管理的关键区域。

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：BasedontheseismicdatagatheredinpastyearsandthecorrelationbetweentheseaandlandareasoftheLowerYangtzePlatform,thestructuralcharacteristicsoftheSouthYellowSeaBasinsincetheIndosiniantectonicmovementisstudiedinthispaper.ThreestagesofstructuraldeformationcanbedistinguishedintheSouthYellowSeaBasinsincetheIndosinian.Thefirststage,LateIndosiniantoEarlyYanshanian,wasdominatedbyforelanddeformationincludingboththeupliftingandsubsidencestagesunderanintensivelycompressionalenvironment.Thesecondstage,whichiscalledtheHuangqiaoEventinthemiddleYanshanian,wasachangeforstressfieldsfromcompressiontoextension.Whileinthethirdstage(theSanduoEvent)intheLateHimalayan,thebasindevelopedadepressionintheNeogene-QuatemaryafterriftingintheLateCretaceous-Paleogene.Thelong-timeevolutioncontrolled3basinformationstagesfromaforelandbasin,thenafaultbasintoafinaldepressionbasin.Inconclusion,sincetheIndosinian,theSouthYellowSeaBasinhasexperiencedcompressionalfoldandthrust,collisionalorogen,compressionalandtensionalpulsation,strike-slip,extensionalfaultblockandinversionstructures,compressionandconvergence.TheNE,NEE,nearlyEWandNWtrendingstructuresdevelopedinthebasin.Fromwesttoeast,thestructuraltrendchangedfromNEEtonearEWtoNW.Whilefromnorthtosouth,theychangedfromNEEtonearEWwithastrong-weak-strongzoningsequence.Vertically,themarineandterrestrialfaciesbasinsshowa"seesaw"patternwithfoldandthrustintheearlystages,whichisstronginthenorthandweakinthesouthandanextensionalfaultinlaterstages,whichisstronginthenorthandweakinthesouth.Inthemarinefacies'basin,thrustdeformationismoreprevailingintheupperstructurallayerthanthatinthelowerlayer.ThetectonicmechanismintheSouthYellowSeaBasinismainlyaffectedbythecollisionbetweentheYangtzeandNorthChinaBlock,whilethestressenvironmentoflarge-scal

简介：since和for均可与现在完成时态连用。被它们引出的时间状语所修饰的动词必须是延续性动词，如果是终止性动词则应转化为延续性动词。例如：

简介：Bothhistoricallyandstrategically,theMediterraneanasacrossroadsandbridgebetweenEurope,AsiaandAfricaisimportantfortheEUwithoutanydoubt.MarkusHahnobserved"Asearlyas1992,theEuropeanCouncilemphasised

简介：自从2003，这篇论文考察中央规模天气动力学的主要理论进步，包括：(1)平衡并且失衡的流动的动态机制被使用学习中央规模循环的开始和发展问题。对称的不稳定性和横向波浪的不稳定性在线和旋涡空气传送对流被分析，并且进一步的研究在非线性的对流对称的不稳定性上被做了。在强迫对流和不稳定的传送对流和中央规模运动的波浪特征之间的相互作用也被讨论。(2)动态边界层建模的中间的空气被开发。复杂非线性的相互作用在大气的边界层和自由大气层之间理论上被分析。低级前面的地形学边界层和另外的边界层的结构动态问题被讨论。(3)在东亚空气发行量的背景下面的meso-β-scale暴风雨的形成和发展与MPV(潮湿的潜在的涡度)的变化被诊断异例。，并且在潮湿的空气。

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

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

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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)

简介：TheearthquakeactivityanddamageinmainlandChinain2003arereviewed.Therewere27earthquakeswithamagnitudeofover5.0,resultingin319peoplekilledand7147peopleinjured.Thetotaleconomiclossofover560millionUSdollarsrepresentsthehighestfigureformainlandChinasince1977,anditiscomparabletothetotallossduringonedecadeinthe1980's.ForthefirsttimeChinaInternationalSearchandRescue(CISAR)teamsweredispatchedtodisasterareasinChina,Algeriaandlran.

简介：TheXinjiangUygurAutonomousRegion(alsocalledXinjiangforshort),situatedintheborderareaofnorthwestChinaandthehinterlandoftheEurasianContinent,occupiesanareaof1.6649millionsqkm,accountingforonesixthofChineseterritory.Ithasalandborderof5,600km

简介：AbstractBackground:Understanding the global spatiotemporal pattern of seasonal influenza is essential for influenza control and prevention. Available data on the updated global spatiotemporal pattern of seasonal influenza are scarce. This study aimed to assess the spatiotemporal pattern of seasonal influenza after the 2009 influenza pandemic.Methods:Weekly influenza surveillance data in 86 countries from 2010 to 2017 were obtained from FluNet. First, the proportion of influenza A in total influenza viruses (PA) was calculated. Second, weekly numbers of influenza positive virus (A and B) were divided by the total number of samples processed to get weekly positive rates of influenza A (RWA) and influenza B (RWB). Third, the average positive rates of influenza A (RA) and influenza B (RB) for each country were calculated by averaging RWA, and RWB of 52 weeks. A Kruskal-Wallis test was conducted to examine if the year-to-year change in PA in all countries were significant, and a universal kriging method with linear semivariogram model was used to extrapolate RA and RB in all countries.Results:PA ranged from 0.43 in Zambia to 0.98 in Belarus, and PA in countries with higher income was greater than those countries with lower income. The spatial patterns of high RB were the highest in sub-Saharan Africa, Asia-Pacific region and South America. RWA peaked in early weeks in temperate countries, and the peak of RWB occurred a bit later. There were some temperate countries with non-distinct influenza seasonality (e.g., Mauritius and Maldives) and some tropical/subtropical countries with distinct influenza seasonality (e.g., Chile and South Africa).Conclusions:Influenza seasonality is not predictable in some temperate countries, and it is distinct in Chile, Argentina and South Africa, implying that the optimal timing for influenza vaccination needs to be chosen with caution in these unpredictable countries.

简介：In1982,ChinaandGreatBritainstartednegotiatingthehandoverofHongKong.Asabystandernation,theUnitedStateshadtakenalow-keyattitude,onlyshowingits'interestinmaintainingHongKong’sprosperityandstability.'However,sincePresidentGeorgeH.W.Bushassumedpowerin1989,

简介：基于一0.5?牰'虨宫摤嫕?牰湩楣慰?潣灭湯湥?湡污獹獩儻汩慩?潍湵慴湩`

简介：Byanalyzinghigh-resolutionSPOTimagesandincombinationwithfieldworkandchronometry,threetypicalfault-offsetsitesonthesouth-middleAltynTaghstrike-slipfaultwerestudiedtoobtainthesinistralhorizontalsliprateofthefault.AtAnnanba,theleft-lateralstrike-sliprateonabranchofthesouthAltynTaghfaultis7.5±1.7mm/asince9.36±0.73kaBP.AtSevenSpring,thefaulthasfourbranchesandtheleft-lateralstrike-sliprateononeofthemis2.3±0.5mm/asince13.86±1.07kaBP,anditisdeducedthatthetotalsliprateofallthefourbranchesis6.9±1.5～9.2±2.0mm/asinceHolocene.AtYuemakeqi,theleft-lateralstrike-sliprateofthefaultis10.6±3.0mm/asince4.73±0.38kaBP.Aslip-rateof7～11mm/aonthemiddlesegmentoftheAltynTaghfault(between88°30'Eand93°05'E)sinceHolocenecanbededucedfromthethreesitesmentionedaboveandtheresultissimilartothelatestGPSobservation.