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如图，在空间直角坐标系中有直三棱柱ABC﹣A1B1C1，CA＝CC1＝2CB，则直线BC1与直线AB1夹角的余弦值为（ ）
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高二下学期数学《》真题及答案
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已知在平面直角坐标系中有三点A.﹣21B.31C.23.请回答如下问题1在坐标系内描出点A.B.C.
下列叙述中正确的个数是①在空间直角坐标系中在Ox轴上的点的坐标一定是0bc②在空间直角坐标系中在yO
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如图K.451所示在空间直角坐标系中有直三棱柱ABCA1B1C1CA＝CC1＝2CB则BC1与A
已知在平面直角坐标系中有三点A.－21B.31C.23.请回答如下问题1在坐标系内描出A.B.C.的
如图在直三棱柱ABC—A1B1C1中AA1=BC=AB=2AB⊥BC求二面角B1—A1C—C1的大小
已知在平面直角坐标系中有三点A.-21B.31C23.请回答如下问题1在坐标系内描出点A.B.C.的
如图在空间直角坐标系中有直三棱柱ABC－
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如图在空间直角坐标系中有直三棱柱ABC﹣
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如图K.451所示在空间直角坐标系中有直三棱柱ABCA1B1C1CA＝CC1＝2CB则BC1与A
如图所示在空间直角坐标系中有直三棱柱ABC－sub>1CA＝CC1＝2CB则直线BC1与直线AB1夹
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如图直三棱柱ABC﹣A1B1C1的所有棱长都是2以A为坐标原点建立空间直角坐标系则顶点B1的坐标是
在空间直角坐标系O.－xyz中有8个点P.1111P.2－111P.7－1－1－1P.81－1－1每
如图所示的空间直角坐标系直三棱柱ABCA1B.1C.1中|C.1C.|＝|CB|＝|CA|＝2AC⊥
如图在直三棱柱ABC—A1B1C1中AA1=BC=AB=2AB⊥BC求二面角B1—A1C—C1的大小
如图在空间直角坐标系中有直三棱柱ABC﹣A1B1C1CA=CC1=2CB则直线BC1与直线AB1夹角
如图在平面直角坐标系中△ABC的三个顶点的坐标分别是A.-25B.-43C.-11.1作出△ABC向
如图直三棱柱ABC—A1B1C1中底面是以∠ABC为直角的等腰直角三角形AC=2aBB=3aDoA
如图所示在平面直角坐标系中已知A.01B.20C.43.1在平面直角坐标系中画出△ABC并求△ABC
如图在空间直角坐标系中有直三棱柱ABC－
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假定英语课上老师要求同桌之间交换修改作文请你修改你同桌写的以下作文.文中共有10处语言错误每句中最多有两处.每处错误仅涉及一个单词的增加删除或修改.增加:在缺词处加一个漏字符号∧并在其下面写出该加的词.删除:把多余的词用斜线\划掉.修改:在错的词下划一横线并在该词下面写出修改后的词.注意:1.每处错误及其修改均仅限一词;2.只允许修改10处多者从第11处起不计分.Itisessentialtotakeanusefulsummervacationaftertheexam.Therearemanykindsofactivityforustotakepart.Firstwecanvisitourrelativesandfriendsorspendahappilytimewithourfamily.Secondseeingafilmlisteningtomusicorhangoutwithourfriendswillalsobeexcited.Thirdweshouldtakemoreexercisetokeephealthy.What'smorewe'dbettertoreviewwhatwehadlearnedatschool.Finallyitisnecessaryofustodosomehouseworkthatcanhelpourparentsalot.AboveallIhopeallofuscanhaveapleasantvacation.
TheWorld'sGreatestBookstores CafebreriaElPénduloMexicoCityMexico PartcafepartcoffeehousepartbarandpartbookstoreCafebreriaElPénduloislocatedinMexicoCity.Bookslinetheshelvesfromtheceilingtothefloorandliveplantsaddlotsofgreen.Thestoreisnamedforahugependulum钟摆hangingfromitsceiling. StanfordsLondonandBristolEngland Establishedin1853Stanfordsboaststhatitofferstheworld'slargestselectionoftravelbooksandmaps.Italsosellstravelaccessories.LookfortheenormousNationalGeographicMapoftheWorldintheflagshipstoreinLondon;itwascreatedin2003tocelebratethestore's150thbirthday. RizzoliNewYorkCityNewYork ForalmostahalfcenturyRizzolihasbeenconsideredasoneofthebestindependentbookstoresintheUS.Itspecializesinillustrated有插图的booksaboutthewaypeopleworksandlivessuchasfashionphotographydecorationdesigncookingandarchitecture.Takeamasterclassinflowerdesignattendalectureandbooksigningordropinforacookingshoworbookalaunchparty. ElAteneoGrandSplendidBuenosAiresArgentina Oftendescribedasoneoftheworld'smostbeautifulbookstoresElAteneoishousedinanhistorictheatermuchasitwaswhenthetheateropenedin1919.Aftercustomersbrowsetheshelvestheycandrinkcoffeeandlistentomusicfromastagehiddeninredcurtainswheretangodancersonceperformed.Whilemostofthestore'sbooksareinSpanishtheyareavailableinarangeofsubjects. 1WhatisCafebreriaElPéndulonotedfor? A.Thelargershelves. B.Itsuniquesymbol. C.Thetastycoffee. D.Itsinterestinglocation. 2Whichbookstoreisthebestchoicefortravellerstobuyatouristhandbook? A.Rizzoli. B.Stanfords. C.ElAteneoGrandSplendid. D.CafebreriaElPéndulo. 3WhatsubjectarebooksinRizzoliabout? A.History. B.Cartoon. C.Lifestyle. D.Literature.
15分Worldwideeachperson15yearsandolderconsumes13.5gramsofpurealcoholperdayaccordingtotheWorldHealthOrganization.1considerthatnearlyhalfoftheworlddoesn'tdrinkatallthatleavestheotherhalfdrinkinguptheirshare. Alcoholcanhave2significanteffectonyourgoodlooks.Firstitdehydrates使脱水you.Thatcanleaveyourskinlookingparchedandwrinkled.It'salso3linktorosaceaaskinconditioncausingrednessandswellingonyourface. Whileyou'redrinkingyourliver肝脏4processasingledrinkwhichisonaverageanhourbutvaryingforeveryone;someofitleavesyourbodyviayourbreathandsweat. Anotherreason5drinkingcanaffectyourlookshastodowithsleep6evenalittlebitofalcoholcanhelpyoufallasleep7rapidasthealcoholleavesthebodyyoumaysufferthe'reboundeffect.Insteadofstayingasleepthebodyenterslightersleepandwakefulnesswhichappearstoget8badifonedrinksmore.Alackofsleepleadstodarkcirclespuffyeyesandstress.Keepitupandyou'relikely9seemoresignsofagingandamuchlower10satisfywithyourappearance. Sothenexttimeyouheadtothepubforatippleortworemember:Youcouldbepayingapriceforallthatfun
WHO'SWHOINTHEZOO? IsitamazingthattheWHO'SWHOINTHEZOOmakesitfunforyoungchildrentosave?WiththehelpofStandardBank'sKidzAPPandtheBigFiveanimalfriendsteachingyourchildrenaboutmanagingtheircashhasneverbeenmorefun.LettheWHO'SWHOINTHEZOOshowyourlittleoneswhatitmeanstoearnandsavemoneyaswellasshareintheenjoymentofspendingtheirwell﹣earnedcash. Elephant Asyourchildrenusethemobileapptocompletevariousactions﹣achievingsavingsgoalscompletingmissionsandachievingwishes﹣herevariousmedalswillberewarded. Earnedmedalsaredisplayedintheelephanthabitataswellaslockedmedalsstilltobeachieved. Leopard Rewardyourkidswithpocketmoneyforcompleting‘missions':householdchoresachievementsetc. Youcancreateamissionforyourchildoryourchildcanrequestanewmission.Oncecreateditmustbeaccepted.Themissionneedstobecompletedbyyourchildandapprovedbyyoubeforeyoucanpayhimorher. Lion Helpyourchildrencreateandfulfilwishes.Wishcardsandtheirsavingsprogresscanbetrackedfromyourbankingapp. Oncetheirsavingsgoalisreachedlionwillinformyouoftheirachievement. Buffalo Kidzcanrequesttowithdrawcashorpurchaseairtimeanddatausingtheirsavings. Rhino Rhinoshowsyourchild'slatestaccountbalanceandtransactions. DownloadtheStandardBank'sKidzAPPfromAppleAppStoreonthephone.UsethecommentsectiontointeractwithotherStandardBankcustomersandbankconsultants. 1WhatistheWHO'SWHOINTHEZOOdesignedfor? A.Playersofboardgames. B.Kidsforself﹣servicebanking. C.Parentsforonlinebanking. D.Travelersinthezoo. 2Rewardswillbepaidif. A.thekidsfulfilyourcreatedmissions B.yourkidsgetenoughlockedmedals C.youkeeptheaccountbalanced D.youapprovetherequestviaKidzAPP 3Whichofthefollowinganimalsisrelatedtospending? A.Rhino. B.Leopard. C.Lion. D.Buffalo.
函数fx＝sin2x+φ0＜φ＜π的图象如图所示为了得到gx＝sin2x的图象可将fx的图象
假定你是李华你的澳大利亚朋友Mike写信告诉你他将参加他所在城市举行的我所了解的中国传统节日'的演讲比赛希望你能为他推荐一个中国传统节日请你给他回信要点包括:1.收信时的感想2.推荐并介绍中国节日;3.预祝对方取得好成绩注意:1.词数100左右可以适当增加细节以使行文连贯2.文章开关和结尾已给出不计入总词数DearMikeYoursLiHua
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AnattendantatapopulargardenintheheartofTokyohascostthefacilitymillionsofyenbecausehewastoofrightenedtoaskforeignvisitorstopaytheadmissionfee.Theattend﹣antwhoisinhisearly70sadmittedfailingtocollectthefeesforShinjukuGyoennationalgardenafteraninvestigation调查wasconductedfollowingatip﹣offbyanotheremployee. Theunnamedmanwhohassinceretiredreportedlysaidhehadstoppedcollectingadmissionfeesof200yenforadultsand50yenforchildreninApril2014andhadcontinuedtodosoforabouttwoandahalfyears.Asaresultapproximately160000peopleenteredthegarden一locatedashortwalkfromShinjuku'sskyscrapersandtheworld'sbusiestrailwaystation一withoutpaying.Theenvironmentministrywhichmanagesthegardensaidthisweekthatithadlostatleast25millionyenasaresult. Themansaidhestoppedaskingforeignnationalsforpaymentsafterhewasonceyelledatbyaforeignerbecausehedidn'tspeakgoodEnglishandafterwardsfelttooscaredtospeaktonon﹣JapanesevisitorsShankeiShimbunreports. Themanhandedoutticketswithoutchargingforthemandthenaskedacolleaguewithaccesstothegarden'sdatabasetocancelthesalessotherewouldbenodifferencebetweenrecordedandactualincome.TheruseworkeduntillateDecember2016whenanothermemberofstaffwitnessedhimbehavingstrangelywhengivingatickettoaforeignvisitorandreportedittothemanagement. Theemployeewasfined10%ofhissalaryaccordingtotheShankeiShimbunnews﹣paper.Heaskedtotakeretirementandofferedtoreturnhalfofhisretirementbonusorabout300000yen. 1WhydidShinjukuGyoennationalgardenloseabigfortune? A.ItwassituatedinaremotepartofTokyo. B.Itofferedfavourablepricetoregularforeigners. C.Aticketsellerallowedforeignvisitorsinfreeofcharge. D.Aticketsellerkeptbacksomeadmissionfeesforhimself. 2Accordingtothemanwhatmadethenon﹣Japanesevisitorimpolitetohim? A.Hisuglyappearance. B.Hisserviceattitude. C.Hisdelayedreaction. D.HispoorspokenEnglish. 3WhatdoestheunderlinedwordruseinParagraph4referto? A.Duty. B.Wisdom. C.Trick. D.Guidance. 4Whatdoestheauthorthinkoftheticketseller? A.Hewasshyandfearful. B.Hewasfriendlyandscared. C.Hewashonestandgenerous. D.Hewasmodestandconsiderate.
TheWaystoShowYourLoveWithoutWords It'ssoeasytotellsomeonethatyoulovehimbutcanyoushowyourlovewithoutusingwords?1.Soit'simportanttolearnhowtoexpressyourlovewithoutwords.Herearesomewaystoshowyourlovewithoutwords. ●Cookforthem ManypeopletypicallycookonspecialoccasionssuchasThanksgivingDayChristmasValentine'sDayandbirthdaysbutwhynotcooksomethingspecialforpeopleyoulove?Figureouttheirfavoritemealandtrytomakeittoday.2. ●Sendacarepackage Ifsomeoneyoulovelivesfarawayfromyouwhynotsendhimacarepackage?3.Youcanstillshowthemthatyoureallycareaboutthem.Apackageofthesmallthingsthey'llneedorlikeiswhatyouneedtoshowyourlovewithoutwords. ●Listentothem Oneofthesimplestwaystoshowyourlovewithoutwordsistolistentothem.4.Iftheyaskyouwhetherthey'vetoldyouthisstorybeforewhynotsayYesbutcouldyoutellitagainbecauseI'veforgottensomedetails? ●5 Whenitcomestoshowingsomebodyyoulovethemwithoutusingwordsthewarmthofkissesandhugsisthebest.Whetherit'sakissorahugallletthemknowyoucareorsimplymissthem. A.Physicalcontact B.Maketimeforthem C.Whenitcomestolovedistanceisnotaproblem D.Listentoeachwordtheysayevenwhenit'sboring E.Greatactionsalwaysspeaklouderthangreatwords F.Youcanevencookitandsurprisethepeopleattheirworkplaceorcollege G.It'snotdifficulttopickthephonetocallthemandaskhowtheirdayisgoing
Thehemlock铁杉treesalongtheWappingerCreekNewYorklookhealthy.HoweverscientistGaryLovettsaysthewhiteballswhichprovideprotectionforthebugsarecreatedbyatinyinsect.It'shardtobelievethetinybugcouldkillatree.Howevertreescanendupwithmillionsandmillionsofthepests.Whentherearethatmanyitendsupkillingthetree. ThebugfromEastAsiaisslowlykillingtreesacrosstheUSA.Thetrouble﹣makingbugisjustoneofmanyinvasive入侵的peststhathaveslippedintotheUnitedStates.Theycanhurtotherlivingthingsintheirnewhome. Manyinvasivepestsarriveonwoodenpalletspiledinsideshippingcontainers.Theysupportandseparategoodsandkeepthemfromslidingaround.Invasivepestsoftentunnelintothepallets.Howcanwestoppestsfromridingonpallets?Lovettsaysnewrulesareneeded.Thecompaniesthatmakepalletsdon'twantmorerules.Congresshasaddedanamendment修正案inthe2018FarmBilltotryandpreventthisproblem.HoweverLovettisnothopefulitwillmakemuchofadifference.Palletsarecheckedbyinspectors.Manyaresprayedwithbug﹣killingpesticide.IbelieveinthesystemsaidBrentMcClendonpresidentofTheNationalWoodenPalletandContainerAssociation.Healsosaidshippingcontainersarecheckedverycarefully. Stilleachyear13millioncontainersareshippedtotheU.S.Eachisfullofwoodenpallets.Lovettsays:Inspectorscan'tpossiblycheckeverything.Allittakesareafewbadpallets;weshouldgetridofwoodenpallets.Hebelievespalletsshouldbemadeofplasticoreco﹣compositewood.Eco﹣compositewoodisamixofwoodfiberandplastic.Insectscannothideintoit.Oneproblemisthatthesechoicescostmore.Theymaybeworththeextramoneythough.InvasivepestscosttheU.S.﹩5billionayear.Treesdon'tjustdieinforests.Theyalsodieincitiesandouryards.Thentheyneedtobereplaced.Thatcostsmoneytoo. 1AllthestatementsareTRUEexceptthat. A.pesticidehasbeenappliedtobug﹣killing B.thecompaniesmakingpalletsdon'twantmorerules C.invasivepestshideinpalletsusedinshipping D.invasivepestsarenativetoWappingerCreek 2Whatcanweinferfromthepassage? A.Bugswon'tbotherthetreeifjustinfewnumbers. B.Bugsruintheshippinggoodsslowly. C.Bugscanbeeasilyspottedbyeyes. D.Bugscovertreeswithwhitesoftballsforprotection. 3WhydoesGaryLovettwanttogetridofwoodenpallets? A.Becauseinsectsmostlydieinthem. B.Becausetheyarethemajorpestcarriers. C.Becausetheyarenotworthextramoney. D.Becauseplasticpalletsareeco﹣friendly. 4Whatdoesthepassagemainlytalkabout? A.Congresscontributesalottodealingwithinvasivepests. B.Effectivemeasureshavestoppedthepestinvasion. C.InvasivepestsareharmingplantsintheUSA. D.EcosystemintheUSAispoorlydamagedbyinvasivewoods.
LettersasawayofcommunicationhavelonggivenwaytophonecallsandWeChatmessages.ButaTVshowLettersAliveishelpingbringthisoldwaytokeepintouchback1thepresent. LettersAlivetook2itideafromaUKprogramLettersLivereleasedin2013.Both3showfeaturefamousactorsandactressesbutthere4benoeye﹣catchingvisualeffectsoranyregularshowbiz娱乐圈activities.Insteadit'sjustaliveevent5remarkablelettersselectedfromawidetimespanandadiverserangeofsubjectsareread.ThereisforexampleapassionateletterfromHuangYongyutoplaywrightCaoYu30yearsagotocriticizehislackof6create. Everyletterislikeasmallpieceofhistory.Byhearingthem7readit'sasifwearebeingsentbackintimetoexperienceamomentthatwewouldotherwiseneverhavehadthechanceto. Comparedto8publishtextslettersalso9naturalcomewithapersonaltouch.AswellascelebratingthepainjoywisdomandhumorLettersAlive10committopromotingChineseliteraturesincefirstrun.
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Ofallthepotentialconsequencesofclimatechange一risingsealevelsdesertificationflood一here'sonethatmaynotcatchyourattention;risingtemperaturesareturningyounggreenseaturtle海龟populationsalmostentirelyfemaleaccordingtoanewstudypublishedinCurrentBiology.ThisisoneofthemostimportantconservationpapersofthedecadeDavidOwensabiologistnotparticipatingintheresearchtoldtheWashingtonPost. Thestudylookedat200000nestingfemalesalongtheeastcoastofQueenslandAustralia一hometooneoftheworld'slargestgreenseaturtlepopulations.Researchersfoundalittlefemalesexbias偏差inthecoolersouthernGreatBarrierReefwith65to69percentofbabyturtlesbornfemale.Butinthewarmernorthernparttheyfoundanextremelyfemalesexbiaswheremorethan99percentofyoungturtleswerefemales.Overall86.8percentofadult﹣sizedturtlesintheentireareawerefemales. Withaverageglobaltemperaturepredictedtoincrease4.7degreesFahrenheitby2100manyseaturtlepopulationsareindangerofhigheggdeathandfemale﹣onlybabyturtleproductionthereportwarned.Thetrendofmorefemalesbeingborninwarmerareashasbeenobservedforafewdecadesbutbiologistswereunawareofhowbigtheseximbalancehadbecome. Biologistsconsider84.74degreesFahrenheittobethekeytemperatureforgreenseaturtlestohebornamixtureoffemalesandmales.Acoupleofdegreesbelowandyougetmostlymales;acoupleofdegreeshigherandyougetmostlyfemales. DermotO'GormanchiefadministratorofWorldWildlifeFundAustraliathinksanydangerstoseaturtlesarelikelytoaffectentireoceanecosystems.Therearesomepotentialquickfixeslikesettingupshadeclothtocoolbeachesandreducingturtlefishingtoinsureadultmalesstayinthepopulation.Buttheonlyeffectivesolutionistostopthechangeintheworld'sclimatehesays. 1WhatdidtheresearcherfindinthenorthernGreatBarrierReef? A.Nearlyallbabyturtleswerebornfemale. B.Turtleseximbalanceincreasinglyreduced. C.Therewereequalamountsofmalesandfemales. D.Thereexistedtheworld'slargestpopulationofseaturtles. 2Whatcanwelearnaboutgreenseaturtles? A.Warmertemperaturemeanlessfemales. B.Theirsexrateisdeterminedbytemperature. C.Theireggshatchmorequicklyincoolerplaces. D.Theirnestsproducethehealthiestmalesat84.74°F. 3WhatdoesDermotstressparticularlyindealingwithseaturtleproblem? A.Preventingclimatechange. B.Protectingadultmaleturtles. C.Usingshadeclothtocoolbeaches. D.Banningpeoplefromfishingturtles. 4What'sthemainideaofthetext? A.Seaturtlesreminduswhat'sgoingonintheoceans. B.Climatechangeisturningbabygreenseaturtlesfemale. C.It'stimetorealizethepotentialeffectsofglobalwarming. D.Risingtemperatureshavecausedseriousproblemstowildlife.
如图圆O的半径为1A是圆上的定点P是圆上的动点角x的始边为射线OA终边为射线OP过点P作直线OA的垂线垂足为M将点M到直线OP的距离表示为x的函数fx则y＝fx在[0π]的图象大致为
IwasstressedoutwhenIwasstudyingformygraduateprogram.Justafewmonthsbeforethegraduation1IhadtoldmymornthatImight2graduateschool.Shelistenedtomy3andsheadmittedforthefirsttimeinourhistoryshewasabit4.Howevershesaidshelovedmeandshe5howmuchstressIwasunder.ThenshetoldmeIwas6thanthisandencouragedmetotakesometimeto7it. SoIdid.IspentthesummerbeforeIwentbacktoschool8whatIhaddonesofarandwhatIhad9todo.Asacreativewriting10Ihadtakenallofmyrequiredcourses.Allthatremainedinmylastyearwere11coursesandmyresearchhours.Ialsohadtwomajorexamsgraduatepapersandtheoral12allduethatyear.Finallywithmymother's13Imanagedtocompletethem. 14mymomIhadafewothergraduatestudentswhoIwasabletospeaktoandprofessors15meintotheirofficeswheneverIneededhelp.They16atmygraduationpartymygoingawaypartyandonmysocialmedia.Graduateschoolwas17stressfulbutwithoutitIwouldneverhaveknownhowstrongandindependentIreallywasandIwouldneverhave18thefriendsIdid. TrustmewhenIsaythatyou19canturnyourcant'sintocansandachieveyourdreams.Allittakesissome20determinationandwillpower. 1A.year B.project C.exam D.anniversary 2A.graduatefrom B.dropoutof C.adjustto D.breakawayfrom 3A.sorrow B.interest C.anxiety D.anger 4A.amused B.embarrassed C.moved D.disappointed 5A.understood B.roved C.promised D.regretted 6A.luckier B.weaker C.cleverer D.stronger 7A.explain B.resist C.consider D.accept 8A.suspecting B.declaring C.guaranteeing D.reflecting 9A.left B.interrupted C.searched D.avoided 10A.tutor B.major C.fan D.model 11A.active B.training C.optional D.writing 12A.argument B.defense C.charge D.bargain 13A.permission B.payment C.encouragement D.control 14A.Regardlessof B.Inexchangefor C.Owingto D.Inadditionto 15A.persuaded B.welcomed C.forbade D.ignored 16A.lookedout B.hungaround C.madeup D.showedup 17A.obviously B.occasionally C.hardly D.hopefully 18A.betrayed B.made C.accompanied D.offended 19A.again B.only C.too D.already 20A.support B.respect C.attraction D.impression
Chinahascompleteditshome﹣grownBeiDouNavigation导航SatelliteSystemBDSwiththesuccessful﹣launchoftwomoreBDS﹣3satellites19inallandhasstartedprovidingservicestocountriesparticipatingintheBeltandRoadInitiativeBRIsincetheendof2018. TheBDSwhichwillcompeteagainsttheUS'GlobalPositioningSystemGPSwillprovidehigh﹣precisionreliablepositioningnavigationandtimingservicesanywhereintheworldbytheendof2020. TheBeltandRoadInitiativeisanambitiousefforttoimproveregionalcooperationandconnectivityinatrans﹣continentalrange.Theinitiativeaimstostrengtheninfrastructure基础设施tradeandinvestmentlinksbetweenChinaandsome65othercountries.ItisalsoexpectedtoincreaseBeijing'sinfluenceinthesecountries. ThisisakeystepfortheBDSdevelopingfromaChinesehomesystemtoaregionalandthenaglobalnavigationsystemsaidYangChangfengchiefdesigneroftheBeiDousystem Chinaplanstolaunchanother11BDS﹣3satellitesbetweentheendof2018and2020.ChinadevelopedtheBDSthroughauniquetechnologicalapproachcontributingChinesewisdomtothetheoryandconstructionofinternationalsatellitenavigationsystems. Altogether18BDSsatelliteshavebeensentintospacein2018makingthisyearthemostintensivelaunchoftheBDSsatellites.Theyimprovedtheirworkefficiencybyreformingthemanagementprocess.Thenumberofsatellitestaffatthelaunchcenterhasbeenreducedbynearlyhalfandthetestingtimebeforelaunchhasbeenshortenedbynearlyathird.IntheCASTproductionbaseinBeijingseveralBDSsatellitesarebeingmanufacturedatthesametime.Theytrytoimproveintelligentmanufacturingcapabilityandcutdownproductiontimes.ConstructionoftheBDS﹣3systemhasaccelerated. OncetheBDSisfullycompleteditwillbethefourthglobalsatellitenavigationsystemaftertheUSGPSsystemRussia'sGLONASSandtheEuropeanUnion'sGalileo.IndiatooisbuildingitsnavigationalsystemcalledtheIndianRegionalNavigationSatelliteSystemIRNSSwithanoperationalnameofNAVIC. 1WhencantheBDSofferglobalservices? A.In2018. B.In2019. C.In2020. D.In2025. 2WhatcantheBDSdonow? A.TaketheplaceoftheGPSoftheUSA B.Watchanyoneanywhereintheworld. C.ControltheBeltandRoadcountries. D.ServetheBeltandRoadInitiative. 3Whatdoesparagraph4mainlytalkabout? A.TheuniquecharactersoftheBDS. B.TheChinesetechnologyoftheBDS. C.TheeffortsofthestaffoftheBDS. D.ThedifficultiestheBDShastodealwith. 4Whatcanbethebesttitleforthetext? A.China'sBDSisapproachingitsgoalstepbystep B.China'sBDShasbecomethefourthglobalsatellitenavigationsystem C.China'sBDShelpsBRIincreaseBeijing'sinternationalinfluence D.TheuniquetechnologicalapproachmakesChina'sBDSoutstanding
BackinJanuaryIwaswatchingacollegefootballgameandcametoarealization:AsahighschoolseniorprettysoonI'llbethesameageassomeofthetopathletesintheworld. Thisrealizationwasbothconfusingandcomforting.UntilthispointI'dalwaysthoughtoftopathletesinanothergeneration.IhadnorealconnectiontopeopleinthenewsorplayingsportsonTVbecausetheyweresomucholder.Butprettysoonpeopleofmyagewillbetheonesdominating支配thenews. ThecomfortcameinunderstandingthatasIpreparetograduatefromSanfordH.CalhounHighSchoolinMerrickI'mnotthatfarofffromenteringtherealworldandIwillhaveachancetomakeanameformyself. RightnowI'mattheendofoneoflifestageswithmanymoretocome.Asseniorsmanyinmyclassdevelopedsuperioritycomplexes.We'dseebabyfacedninthgradersandthinkUghthoseannoyingfreshmen.Orwe'dhearjuniorscomplainaboutstartingthecollegeapplicationprocessandsaytoeachotherThosejuniorshavenoideawhatthey'retalkingabout.Ofcourselastyear'sseniorssaidthesamethingaboutlastyear'sjuniorsrepeatingatimelesscycle. PsychologistandauthorThomasArmstrongwritesthatlifeismadeupof12stages.Hestressesthatnostageismoreimportantthananotherandeachhasitsownuniquegifts.Thereisnohighestpointinlifenoimpressiveendingwhenyouareaboveeverybodyelse.Atthesametimethereisnolowestpointinlife;atnopointisahumanworthlessandbelowothers.Justasaninfantisn'tbeloweveryoneelseoureldersaren'taboveeveryoneelse. 1Whatcanweknowabouttheauthor? A.He'llfinishhishighschoolstudiesaboutoneyearlater. B.Reflectingonthepastisapartofhisdailyroutine. C.Footballisaparticularfavoritewithhim. D.Hedreamsofbeinganexcellentathlete. 2Whydidtheauthorfindhisrealizationcomforting? A.Thetopathletesarethesameageashim. B.Thereisapossibilitythathecanbefamous. C.Hewillbeadmittedtohisdreamuniversity. D.He'smadefullpreparationsforenteringsociety. 3WhatdoestheunderlinedphrasesuperioritycomplexesinParagraph4mean? A.Ahabitofmakingcomplaints. B.Ahabitoffollowinginothers'footsteps. C.Afeelingthatyouarebetterthanothers. D.Afeelingthatothersareunapproachable. 4Whatmessageisconveyedinthelastparagraph? A.Lifeismeanttobelivedandenjoyed. B.Lifeisneversmoothfullofupsanddowns. C.Oneshouldtrytoreachhisgreatestpotential. D.Everyonehastheirownvalueandpositioninlife.
Areyoucontentwiththeshapeofyournose?Ifnottheclimatemaybetoblamenotyourparents. AccordingtoarecentstudycarriedoutbyscientistsfromPennsylvaniaStateUniversityUSclimateplayedakeyroleinshapingournoses.Thefindingswerebasedonanexaminationofthesizeandshapeofnosesof476peoplefromfourregions﹣WestAfricaEastAsiaSouthAsiaandNorthernEuropeusing3﹣Dfacialimagingtechnology. PeoplehavethoughtforalongtimethedifferenceinnoseshapeamonghumansacrosstheworldmayhavearisenasaresultofnaturalselectionbecauseofclimateArslanZaidioneoftheleadauthorsofthestudytoldTheGuardian.ButwhilepreviousstudieswerebasedonmeasurementsfromhumanskullsZaidiandhisteamlookedatnoseshapeitself. Theresultshowedthatwidernosesaremorecommoninwarmandhumidclimatewhilenarrowernosesaremorecommonincoldanddryclimate.ThatZaidisaidcouldbebecausenarrowernasalpassageshelptoincreasethemoisture潮湿contentofairandwarmitwhichiseasieronourlungs.Thisinturnledtoagradualdecreaseinnosewidthinpopulationslivingfarawayfromtheequator. MorestudiesarestillneededtotestthelinkbetweenclimateandnoseshapebutZaidibelievesthecurrentfindingsarevaluableinunderstandingpotentialhealthissues.AswebecomemoreofaglobalcommunitywearegoingtocomeacrossclimatethatwedonotadapttohetoldTheGuardian.Thismeansmovingtoaverydifferentclimatemightincreasetheriskofbreathingproblems. HoweverheaddedThismaynotbenecessarilytrueforvariousreasonssuchasofmodernmedicineandthefactthatourcurrentclimateisverydifferentfromwhatitusedtobe. 1FromthepassageweknowmostpeoplefromSingaporehavenoses. A.wider B.narrower C.smaller D.larger 2Narrowernosesarehelpfulto. A.cooltheair B.warmtheair C.takeinmoreoxygen D.drytheair 3Whatcanbelearnedaboutthestudy? A.Zaidi'steammeasuredhumanskullsusing3﹣Dtechnology. B.Theshapeofournosesisdeterminedbyourparents. C.Noseshapehelpspeopleadapttotheenvironment. D.It'scertainthatpeoplewillsufferfrommorebreathingproblems. 4Whichofthefollowingcanbethebesttitleforthepassage? A.Whatfactorsshapenoses? B.Howtomakeyournoseattractive? C.Noseshapecausesbreathingproblems D.Climateshapesnoses
假定你是李华你的朋友Peter想了解你校于五月举办的中国传统文化艺术节.请你给Peter写封回信内容包括: 1.举办艺术节的目的; 2.介绍你最喜欢的一个艺术节活动; 3.邀请Peter参加并告之艺术节活动的时间. 注意: 1.词数100左右; 2.可以适当增加细节以使行文连贯.
已知函数．有以下结论 ①fx的图象关于直线y轴对称②fx在区间上单调递减 ③fx的一个对称中心是④fx的最大值为 则上述说法正确的序号为．请填上所有正确序号
Wheneveryoufeelcold.thefirstthingyoudoistoputonmoreclothes.Butitcanhappenthatyoucanfeelcolderwhenyougooutsidewiththesameamountofclotheson1youdoindoorsWhyisthis? AccordingtoTheConversationthereason2lieincoldreceptors接收器intheskin.Whenthetemperaturedrops.thesereceptorssend3signaltotellthebrainthebodytemperature.Thenbraincreates4awareoffeelingcold. 5wearmoreclothesathomeleadstoaveragebodytemperaturebeingraised.Thenthereceptorssendthebrainthesignalofa6hightemperature.Howeverwhenyougooutsideyournervoussystemlearnsthetemperature7yourskin.inparticulartheface.Asaresultthedifferenceintemperatureisnowgreaterandyoufeeltheairiscolderparticularlyonthe8exposeskin. 9accordingtoTheSun.onceyougetoveryourinitialsenseofcoldnessyourcoatwillstilldoitsjobandyou10feelitsbenefit.
假定你是李华你每周日上午都会去交换生Alice那里教她制作中式早餐.本周日的安排因你爷爷生日而改到下午.请你给她写封邮件内容包括: 1.本周学习时间变更及原因; 2.本周学习内容:制作包子steamedstuffedbun; 3.课前准备:面粉猪肉及蔬菜. 注意: 1.词数100左右; 2.可以适当增加细节以使行文连贯.
如图所示在平面直角坐标系中锐角αββ＞α的终边分别与单位圆交于AB两点点A． 1若点B求cosα+β的值 2若求sinβ．
在锐角△ABC中若A＝30°BC＝4AC＝4则角B的大小为
Iwasalovelychildwithalovingfamily.Iwasnotan1butaleaderinschool.Butwhatmademespecialwasnotseenfromtheoutside:Iwas2aboutlife.Mybestqualitywasmypersonality. Atagetwelvemylifehadabreakdown.ItwasthenthatIdevelopedOCD强迫症.Iwasnolongerthe3girl.IfinallytoldmymotherIwassufferingfromdepression.Istartedtakingmedicine4themedicinedidhelp.Butonethingdidn't5:Istillwasoverwhelmedwithdepression.Istillwas6sadandIstartedtobelievethatmylifenolonger7. Thinkingmylifenolongerhad8.Idecidedleavingtheworldwasthesolution.IwroteanotetoallmyfriendsandfamilyexpressingIwas9forleavingthem.AsIwasfoldingthenotemyeyesfellonaphotograph.Itwasalittlegirlwearingacarefreesmile. Ittookmeafewminutesto10whothegirlinthephotowas.I11couldn'tbelievethatsmilingchildwasme!Itseemedmyyoungerselfhadsentmea12.RightthenandthereIknewIcouldn't13myself.OnceIhadbeenastronggirlandIhadtobelikethatagain.IsworeIwouldn'tonly14mymedicine.Iwouldfightthedepressionwithmy15too. It'sbeentwoyears16Irecovered.TherealreasonI'm17isthatIrefusedtoletdepression18mylife.Ilearnedalifelong19:Nevergiveup.Lifeisgood.Everyonehas20inlifebuteveryonecansurvive.Iamlivingproofofthat. 1A.follower B.winner C.listener D.organizer 2A.curious B.upset C.concerned D.enthusiastic 3A.beautiful B.brave C.happy D.casual 4A.Afterall B.Infact C.Inaddition D.Bychance 5A.matter B.occur C.change D.arrive 6A.occasionally B.constantly C.naturally D.rarely 7A.counted B.existed C.turned D.appeared 8A.destination B.advantage C.impact D.meaning 9A.grateful B.sorry C.responsible D.suitable 10A.explain B.assume C.realize D.acknowledge 11A.never B.only C.still D.even 12A.chance B.letter C.greeting D.message 13A.forgive B.kill C.control D.betray 14A.relyon B.takeover C.bringin D.pickout 15A.mind B.choice C.decision D.imagination 16A.after B.since C.before D.when 17A.educated B.praised C.healed D.accepted 18A.break B.define C.fail D.ruin 19A.memory B.story C.lesson D.concept 20A.challenges B.promises C.opportunities D.options
已知向量＝1的夹角为45°若则＝
某书店刚刚上市了中国古代数学史销售前该书店拟定了5种单价进行试销每种单价x元试销1天得到如表单价x元与销量y册数据 1根据表中数据请建立y关于x的回归方程 2预计今后的销售中销量y册与单价x元服从1中的回归方程已知每册书的成本是12元书店为了获得最大利润该册书的单价应定为多少元 附．
Wearesurroundedbymessagestryingtogetourattention.Advertiserspoliticiansandothergroupsalltrytogetustoagreewiththem.1.Propagandaisnotalwaysabadthingbutitoftenhidesthetruthaboutatopic.It'sverysimilartoadvertisingwhosegoalistogetpeopletobuysomethingwhilepropagandaistochangewhatpeoplebelieve. PropagandaTechniques Tocreatepropagandaacommontechniqueisname﹣calling.Apoliticianmightcallsomeoneatraitororliarwhichmakestheotherpersonlookbad.Anotheristhetrendtechnique.Peoplewanttobeonthesideinthefavor.2.Somepropagandaisbasedonfear.Itscarespeopleintochoosingacertainsideortakingactionwhichmightnotbebad.Anti﹣smokingcampaignsareoneexample.Theymayscarepeopleintothinkingthatiftheysmoketheywillgetcancer. 3Propagandaisusedbymanygroupssuchasbusinessespoliticiansandthegovernment.Itisspreadthroughposterstelevisionandradio.TheInternetmakesiteasytosendmessagestothewholeworld. TypesofPropaganda Politicalpropagandahasbeenaroundaslongastherehavebeenpoliticians.4.Peoplehaveuseditformanyyears.WarpropagandabeganduringWorldWarImorethan100yearsago. Toseeifpropagandaissayingthetruthpeopleneedtodoextrawork.Forexampleadsmightalwayssoundlikethey'retrue.Butbeforeyoubelievethemtrytothinkaboutwhocreatedandpaidforthem.Findoutwhytheydidit.5. A.PropagandaTargets B.PropagandaMediums C.Anotherwordforthisispropaganda D.Somostpeoplewillagreewiththosepoliticians E.Thenyoucandecideifthey'rebeinghonestornot F.Howeverreligiouspropagandawasactuallythefirstofficialone G.Peoplemightjoinsomeonewhoclaimstobepopularorwinning
假定英语课上老师要求同桌之间交换修改作文请你修改你同桌写的以下作文.文中共有10处语言错误每句中最多有两处.每处错误仅涉及一个单词的增加删除或修改. 增加:在缺同处加一个漏字符号˄并在其下面写出该加的同. 删除:把多余的词用斜线\划掉. 修改:在错的词下画一横线并在该词下面写出修改后的词. 注意:1.每处错误及其修改均仅限一词; 2.只允许修改10处多者从第11处起不计分. Lastweekourschoo1holdaphotographycompetitionwhatthemewasAnActofKindness.Moststudentsshowedgreatinterestbutparticipatedinitactively.Theyalsoexchangedpracticalexperience.AlltheworksshownthroughtheWeChatplatformandtheywonhighlypraisefromthepublic.Twentyoutstandingphotogotthefirstprizeandwereawardedbytheirschool. Anactivityofferedusanopportunitytosharesomuchkindness.Itraisedourawarenessofhelppeopleinneed.Whenwedoanactofkindnessforsomeonewe'reactuallygettingsomethinginreturnfor一pleasure.
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