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如图所示,最大阻值为50Ω的滑动变阻器R和一个标有“6V3.6W”字样的小灯泡L串联后接在电源电压恒为6V的电路中,不考虑灯丝电阻变化,则下列判断不正确的是( )
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如图所示电源电压U=12VR1为定值电阻阻值为100ΩR.为滑动变阻器R.的最大阻值为50Ω电流表量
如图14甲所示电源电压U=10VR1为定值电阻阻值为20ΩR.为滑动变阻器R.的最大阻值为50Ω小灯
如图所示电路灯L.标有3V0.9W.滑动变阻器R.上标有50Ω1A的字样电压表量程为0~3V则灯L.
如图甲所示电路电源电压为12V电阻R.1的阻值为20Ω滑动变阻器R.2的最大阻值为100Ω当开关S.
要测量标有2.5V字样的小灯泡的额定功率现有器材电压恒为6V的电源一个电压表标有50Ω1A的滑动变阻
如图所示电压U.恒定为8VR.1=12Ω滑动变阻器的滑片P.从一端滑到另一端的过程中电压表的示数从3
如图所示的电路中灯L.标有3V0.9W滑动变阻器R.上标有20Ω1A的字样电压表量程为0~3V若电源
如图所示电路电源电压为4.5VR1阻值为5Ω滑动变阻器R2最大阻值为20Ω电流表量程为0~0.6A电
图7所示电源电压为6V.一只标有3V3w的小灯泡与一个最大阻值为9Ω的滑动变阻器串联在保证电路安全工
6 W 4.5V.
4.5 W 6V.
6 W 6V.
9 W 4.5V.
如图所示电源电压为6V一只标有3V3W的小灯泡与一个最大阻值为9Ω的滑动变阻器串联在保证电路安全工
6W 4.5V
4.5W 6V
6W 6V
9W 4.5V
如图所示电路电源电压保持不变当闭合开关S.调节滑动变阻器阻值从最大变化到最小两个电阻的U-I关系图像
电源电压为6V
定值电阻R
1
的阻值为20Ω
滑动变阻器R
2
的阻值变化范围为0~10Ω
变阻器滑片在中点时,电流表示数为0.3A.
如图所示标有6V3W字样的小灯泡与最大阻值为30Ω的滑动变阻器串联在电路中当滑动变阻器连入电路中的电
如图所示电源电压为12V并且保持不变滑动变阻器R.的最大阻值为20Ω小灯泡L.上标有6V3W字样.设
如图所示的电路电源电压U=4.5V且保持不变R1=5ΩR2标有50Ω0.5A字样的滑动变阻器电流表的
在图所示电路中L是标有6V3W字样的小电灯它与定值电阻R和滑动变阻器R组成串联电路电源电压保持8V不
如图所示电源电压为6V灯泡上只标有2V字样变阻器R.的最大阻值是20Ω当滑动头置于中点时小灯泡正常发
如图所示的电路已知电流表的量程为0~0.6
,电压表的量程为0~3V,定值电阻R
1
的阻值为10Ω,滑动变阻器R
2
的最大阻值为50Ω,电源电压为6V.开关S.闭合后,在滑动变阻器滑片滑动的过程中,保证电流表、电压表不被烧坏的条件是( ) A.电压表最小示数是1V
滑动变阻器滑片允许滑到最左端
电路中允许通过的最大电流是0.6A.
滑动变阻器滑片移动的过程中,电流表先达到最大量程
10·柳州图7所示电源电压为6V.一只标有3V3w的小灯泡与一个最大阻值为9Ω的滑动变阻器串联在保证
6 W 4.5V.
4.5 W 6V.
6 W 6V.
9 W 4.5V.
如图所示的电路已知电流表的量程为0~0.6A电压表的量程为0~3V定值电阻R.1的阻值为10Ω滑动变
电压表最小示数是1V
滑动变阻器滑片允许滑到最左端
电路中允许通过的最大电流是0.6A
滑动变阻器滑片移动的过程中,电流表先达到最大量程
如图甲所示电源电压U=10VR1为定值电阻阻值为20ΩR.为滑动变阻器R.的最大阻值为50Ω小灯泡上
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同学们为了制作叶脉书签需要配制400g10%的NaOH溶液. l计算需要称取NaOH的质量g量取水mL. 2将洗净的树叶放在配制好的溶液中煮沸一段时间后取出称量发现溶液的质量减少了200g溶质质量分数也有所减小.然后在剩下的溶液中加入CuSO4溶液直到不再产生沉淀为止向溶液中逐渐加入了16%的CuSO4溶液200克.计算 ①煮沸后剩下溶液中NaOH的质量分数. ②加入CuSO4溶液后刚好完全反应时溶液中溶质的质量分数. 1只需填答案2要求写出计算过程精确到0.1%
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Wheneversomethinglooksinterestingorbeautifulthere'sanaturalimpulse冲动towanttoownandpreserveit﹣whichmeansinthisdayandagethatwe'relikelytoreachforourphonestotakeapicture. Thoughthiswouldseemtobeanidealsolutiontherearetwobigproblemsassociatedwithtakingpictures.Firstlywe'relikelytobesobusytakingthepicturesthatweforgettolookattheworldwhosebeautyandinterestdroveustotakeaphotographinthefirstplace.Andsecondlybecausewefeelthepicturesaresafelystoredonourphoneswenevergetaroundtolookingatthemsosurearewethatwe'llgetaroundtoitoneday. Theseproblemswerenoticedrightatthebeginningofthehistoryofphotographywhentheaveragecamerawasthesizeofagrandfatherclock.ThefirstpersontonoticethemwastheEnglishartcriticJohnRuskin.Hewasatravelerwhorealizedthatmosttouristsmakeaboringjobofnoticingorrememberingthebeautifulthingstheysee.Hearguedthathumanshaveanaturaltendencytorespondtobeautyandwishtohaveitbutthattherearebetterandworseexpressionsofthisdesire.Atworstwegetintobuyingsouvenirsortakingphotographs.ButinRuskin'seyesthere'sonethingweshoulddoandthatisattempttodrawtheinterestingthingsweseenomatterwhetherwehaveanytalentfordoingso. Ruskinwasveryupsetbyhowseldompeoplenoticedetails.HestronglydislikedthetravelerswhopridedthemselvesoncoveringEuropeinaweekbytrain.Ifhebetrulyamannoharmtogoslowforhisgloryisnotatallingoingbutinbeing. 1Peopleareeagertotakepicturesatseeingsomethingbeautifulbecause. A.it'shuman'sborndesireofowning B.it'sconvenienttodosowithamobilephone C.theyareusedtohurryingforeverything D.theycannotwaittoshareitwithfriends 2Whentakingpicturespeoplemay. A.findagoodwaytostoregoodmemoriesintheirminds B.feelithardtolearntheskillsoftakinggoodphotos C.ignoreappreciatingsomethingattractiveonthespot D.havechancestomeetthechallengeofnewtechnology 3Accordingtothelastparagraphtravellingpeopleareusuallyproudof. A.thelongdistancethattheyhavecovered B.thehappyhoursthattheyhavegonethrough C.theadvancedtransporttoolthattheyhavetaken D.thegreatconveniencethattheyhavebeenoffered 4WecanconcludethatRustinattachedimportanceto. A.travellingaroundtheworld B.takingbeautifulphotoswithacamera C.takingphotosinsteadofpaintingpictures D.admiringtheworld'sbeautyattentively
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Whileastronautsinspacegettodomanyexcitingthingstheymissoutonordinarythingsthatwealltakeforgranted﹣beingabletowalkonfirmgroundhangingoutwithfamilyanddiggingintoasliceofhotsteamingpizza.Thoughnotmuchcanbedoneaboutthefirsttwothingstheremaysoonbeasolutiontothethirdonethankstothiscool3﹣Dpizzaprinter! AboutayearagoNASAoffered﹩125000toAnjanContractora3﹣Dtechnologyexperttobuildadevicethatwouldallowastronautstomakepizzaondemand.Themechanicalengineerpromisedthathisinventionwouldproducepiesinlargequantitiesthatlookedtastedandevensmelledlikepizzamadeincommonovens. Latelastyeartheengineerpresentedavideoofhisfirstprototype原型thatbeginsbycreatingasinglesliceofdough面团thatiscookedandprintedatthesametime.Thencomesthetomatosauce﹣amixoftomatopowderoilandwaterandfinallyaproteinslicethatresemblescheese.Whilethevideodoesn'tshowthebakingprocesstheinventorsaysthatoncethepizzaisprinteditcanbereadytobeconsumed消耗in7seconds. WhilethepieinthevideolooksdeliciousenoughtoattractanypizzaloverAnjanContractorisfarfromreadyforastronauts.That'sbecausehestillhastofindasolutiontomakethefoodcontainerintheprinterlastfor30years.Thoughthatmaysoundunrealisticactuallyitisnot.AnjanContractorbelievesthattheonlywaythatispossibleisthatthewaterisremovedfromalltheingredientsandthentheyarereducedtothepowderform.Thisasyoucanimaginewillnotbesoeasy.Butwhiletheprintermaynotbereadyforspaceitcertainlylooksreadyenoughforpeopleonearth.HopefullyNASAandContractorwillconsidersellingittothosenotfortunateenoughtogotoMars! 1Whydoestheauthormentionthethingsthatastronautsinspacecannotdo? A.Toaskusnottotakecommonthingsforgranted. B.Toshowtheyliveadifficultlifethere. C.Toshowtheirlifeisboringinspace. D.Tointroducethetopicofthetext. 2NASAoffered﹩125000toAnjanContractormainlyto. A.createsomenewtypeof3﹣Dprinter B.attractmorecompaniestoworkforNASA C.helpastronautsinspaceenjoyfreshpizzaoneday D.producepizzainlargequantitiestoearngreatprofits 3ThebiggestchallengethatAnjanContractorisfacedwithnowisprobablythat. A.hehasnomoneylefttogoonwithhisresearch B.thepizzadoesn'tseemappetizingtopizzalovers C.hehasnowaytomakepizzathatcanlastforthirtyyears D.hecannotmakethefoodcontainerlastfordecades 4What'sthebesttitleofthepassage? A.NASAistryingitsbesttohelpastronautseatbetter B.Astronautsmaysoonbeabletoenjoysteaminghotpizza C.NASAisworkingonmakingpizzaforcommonpeople D.A3﹣Dpizzaprinterhasbeenusedtomakepizza
Themoonhadgonebehindacloudandthereweren'tmanystarsinthesky.AsItookaglance一瞥atmyneighbor'shouseIsawaflame火焰inhis1.IthoughthewashavingamidnightfastfoodsoIwentbacktomy2. Soontherewasa3smellintheairandIguessedsomethingwaswrong.4Ijumpedoutofbedandwentdownstairsto5.Isawfirecomingoutofmyneighbour'skitchen.RightawayI6Fire!Fire!Buttherewasnoonenearbyto7myshoutsforhelp. I8intomyhousecalledtheFireDepartmentandwentbacktomyneighbour'shouse.Irangthedoorbellhitonthedoorand9myneighbour'snamebuttherewasno10.Imanagedto11thehouseandrescuedacatandarabbit. Itriedtothrowwaterthroughthekitchenwindow12itwasnousethefirewastoostrong.13afireenginearrivedandsoonthefiremenputoutthefire.Theyarrivedjust14asthefirewasgoingto15totheotherroomsinthehouse. Whenmyneighbourcamebackhewas16becausehiskitchenwasburntdownbuthethankedmeforcallingtheFireDepartmentandforsavinghis17.HewantedtogivemesomemoneyinreturnbutIdidnot18it. Weekslatermyneighbourrepairedandrestoredhiskitchen.He19metoseehisnewkitchenandtherehegavemeamedal奖章thathehad20orderedfromafactory.Itmademefeelveryhappy. 1A.sittingroom B.bathroom C.kitchen D.bedroom 2A.chair B.table C.bed D.sofa 3A.big B.hot C.special D.burning 4A.Afterawhile B.Allthetime C.Onceinawhile D.Atonce 5A.examine B.search C.listen D.smell 6A.said B.shouted C.received D.smiled 7A.hear B.listento C.ask D.turnto 8A.walked B.rushed C.jumped D.stepped 9A.calledin B.calledup C.calledout D.calledfor 10A.answer B.light C.sound D.fire 11A.takeout B.takeup C.breakdown D.breakinto 12A.and B.but C.because D.so 13A.Luckily B.Sadly C.Unfortunately D.Suddenly 14A.intime B.ontime C.atatime D.attimes 15A.run B.spread C.flow D.return 16A.glad B.sad C.sick D.angry 17A.children B.parents C.life D.pets 18A.expect B.want C.accept D.get 19A.ordered B.begged C.advised D.invited 20A.mainly B.particularly C.specially D.naturally
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The10thannualInternationalGoSkateboardingDaywillbeheldonJune212012.SkateboardingDayisallaboutfun!Hereisyourguidetosomeoftheeventsaroundtheworld. LosAngelesCalifornia Over10000skateboardersfromaroundtheworldwillgatherinthestreetsofL.A.TheyhavepartneredwithBoardsforBrosanonprofitorganizationthatcollectsandrestores修复skateboardsforchildrenwhocannotaffordtheirownandhaveaskedskateboardersacrosstheUStodonatetheirusedskateboardproducts.Thecelebrationwilllastmostofthedaytime. ManilaPhilippines TheSkateboardingDaytobeheldinthePhilippineswillbeintheManilaforthesecondtime.Manilaishopingtopromotehealthandskateboardingsports.Theeventbeginsat200pmandendsat600pm.TheskateboardersstartfromLiwasangBonifaciowheretheycanskateinthestreetsofP.BurgosRoxasBoulevardanduptoMalatefountaininRajahSolimanParkwheretheeventendswithaProductTossandBestTrickcontest. SylvanLakeAlbertaCanada IfyouhappentobeinAlbertaCanadaandtheweatherisn'tgreatforoutdoorskatingInclineSkate&BMXParkistheplacetogoskateboarding.Inclineisagreatplacetoskateandadaypassthereisonly﹩8foranadulthalfforthosebelow16.OnGoSkateboardingDaytheywillholdacompetitionwiththefirstprizewinnertakinghome﹩600. NewYorkCityNewYork SteveRodriguezownerandfounderofSBoroSkateboardsholdsthebiggestchapteroftheSkateboardingDayintheworld.TensofthousandsofpeoplewillparticipateandJune21stisnowanofficialNewYorkCityholiday.Theeventstartsat10amandendsat6pm.Therewillbeafreeclinicat10amtonsofprizesfoodanddrinks.Fordetailsofthefulldaypleasecheckouthttp://www.Sboro.com. 1ItcanbelearnedthattheBoardsforBrosaimsto. A.provideskateboardsforpoorchildren B.collectusedskateboardproductstothefestival C.searchforcompetitorsforthefestivaleveryyear D.restoreskateboardsonlyforthecompetitors 2Howmuchwilltheypayifacouplewiththeir14﹣year﹣oldchildskateinIncline? A.Eightdollars. B.Twelvedollars. C.Sixteendollars. D.Twentydollars. 3Wherewilltheeventorcelebrationlasttheshortest? A.InManilaPhilippines. B.InLosAngelesCalifornia. C.InSylvanLakeAlbertaCanada. D.InNewYorkCityNewYork.
IlostmysightwhenIwasfouryearsoldbyfallingoffacarandhurtingmyhead.NowIamthirtytwo.Icanvaguelyrememberthebrightnessof1andwhatcolourredis.Itwouldbe2toseeagainbutan3candostrangethingstopeople.Idon'tmeanIwould4togowithoutmyeyes.IsimplymeanthatthelossofthemmademeappreciatemorewhatIhad5. Myparentsandmyteacherssawsomethinginme﹣a6tolive﹣whichIdidn'tseeandtheymademewanttostiritupwith7. The8lessonIhadtolearnwastobelieveinmyself.Iamnottalkingaboutsimplythekindof9thathelpsmedownanunfamiliarstaircasealone.I10somethingbiggerthanthataconfidencethatIamdespitebeing11arealpositivepersonthatthereisaspecialplacewhereIcanmakemyselffit. Ittookmeyearstodiscoverandstrengthenthisconfidence.Ithadtostartwiththeeasyandsimplethings.12amangavemeanindoorbaseball.IthoughthewaslaughingatmeandIwas13.Ican'tusethisIsaid.Takewithyouheurgedmeandrollitaround.Thewords14inmymind.Rollitaround!ByrollingtheballIcould15whereitwent.ThisgavemeanideahowtoachieveagoalIhadthought16beforeplayingbaseball.AtPhiladelphia'sOverbrookSchoolfortheblindI17asuccessfulvariationofbaseball.Wecalleditgroundball. Ihavesetaheadofmeaseriesofgoalsandthentriedtoreachthemoneatatime.Ihadtobeclearaboutmy18.ItwasnogoodtryingforsomethingthatIknewatthestartwas19outofreachbecausethatonlybroughtbitternessoffailure.Iwouldfailanyway20ontheaverageImadeprogress. 1A.sky B.cloud C.sunshine D.mist 2A.helpful B.wonderful C.hopeful D.successful 3A.disaster B.environment C.incident D.wonder 4A.manage B.try C.want D.prefer 5A.lost B.left C.used D.cared 6A.purpose B.potential C.pressure D.preparation 7A.energy B.happiness C.luck D.blindness 8A.hardest B.dullest C.simplest D.easiest 9A.self﹣respect B.self﹣control C.self﹣confidence D.self﹣defence 10A.think B.consider C.guess D.mean 11A.imperfect B.perfect C.unfair D.fair 12A.Later B.Soon C.Once D.Then 13A.worried B.encouraged C.shocked D.hurt 14A.stuck B.impressed C.occupied D.held 15A.see B.hear C.notice D.observe 16A.important B.unimportant C.possible D.impossible 17A.invented B.discovered C.instructed D.directed 18A.experience B.advantages C.knowledge D.limitations 19A.hardly B.wildly C.highly D.deeply 20A.so B.for C.but D.and
“低碳生活”是指生活中所耗用的能量材料要尽量减少从而减低二氧化碳的排放量.下列做法不符合“低碳生活”理念的是
MaryAnningwasanEnglishfossil化石collectordealerandpaleontologist古生物学家.Herfossil﹣huntinghelpedchangethewaypeoplethoughtabouttheworld. MarywasbornintoapoorfamilyinEnglandonMay211799.ShelivedintheseasidetownofLymeRegisinDorset.Thefamilyhadninechildren.OnlyMaryandherbrotherJosephgrewup.Mary'sfathertookhischildrenalongthebeach.Theypickedupshellsandstonestoselltovisitors.Marydidnotgotoschoolmuch.Herfamilywastoopoor.Andschoolsdidnotteachchildrenaboutfossils.Marycouldreadandwrite.Shetaughtherself.Shelearnedaboutrocksandhowbodiesaremade. In1811whenMaryandJosephwerefossilhuntingJosephsawabonestickingoutoftherock.Maryhadahammertochipawayattherock.Verycarefullysheuncoveredit.Shefoundthefirstcompletefossiloftheichthyosaur鱼龙. SincethenMarybecamecrazyaboutfossilhunting.Shelikedtohuntonthebeachafterastorm.Thewindrainandwavesmadetherockscrumble.Itwaseasytospotfossils.MostdaysMarywentfossilhuntingwithherdogTray. RichfriendshelpedMarybysellingfossilsforher.Theysenthermoney.Scientistswrotelettersandcametoseeher.OnegoodfriendwasWilliamBucklandaprofessoratOxfordUniversity.Maryalsoopenedashoptosellfossilsstonesandshells.Shechattedwithvisitors. MaryAnningdiedin1847.Howevolution进化workswasexplainedbyCharlesDarwinnotlongafterMarydied.Herfossilshadhelpedscientistsunderstandhowthingsbegan. 1WhydidMary'sfathertakehischildrenalongthebeach? A.Toenjoylife. B.Tomakealiving. C.Tolookforfossils. D.Toteachthemaboutfossils. 2WhatcanwelearnaboutMary? A.Herfatherwasapaleontologist. B.Herfathereducatedherathome. C.Shehadninebrothersandsistersinall. D.Shemightbepopularatthattime. 3Whowasthefirstonetocatchsightoftherockcontainingthefirstcompleteichthyosaurfossil? A.CharlesDarwin. B.Mary'sdog. C.Joseph. D.Mary. 4Whatdoestheunderlinedwordcrumbleinthefourthparagraphmeans? A.break B.shake C.float D.dive
MarkTwainwasa幽默的writerandhiworksalwaysmakereaderslaugh.
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. It'stimeforustograduate.BeforepartingourclassisgoingtoholdthelastclassmeetingwhichthemewillbethePastGoldenDays.Weplantohaveseveralactivitiestobringaunforgettableendingtoourbeautifuldays.Firstlywewillwatchthephotostakeduringthethreeyearsespecialaboutourschoolevents.Itwillsurelymakeeveryonetorecallthosepreciousmoments.Thenwe'llextendoursinceregratitudetoourteachers.Itisthemwhogivewithoutaskinganythingforreturn.Thencameoneofthemostimportantmomentinourlife﹣﹣abigparty.InawordIhopethelastclassmeetingwillmeaningful.
现有50g溶质质量分数为10%的氢氧化钠溶液加入50g溶质质量分数为10%的硫酸铜溶液充分反应过滤除去沉淀所得溶液中含有离子是
Lastweekinanunusualwayastrangertreatedmewithgenerosity.AtanAsiangrocerystoreonabusyeveningIwasshoppingfortheitemsIneeded1myvoluntaryworkofcookingbreakfastonSaturdayatashelterforthehomelessinSanJose.Iwenttothestore2buytofuandvegetables.AsI3waitinlinetofinishthepurchasetheladynexttomeapproachedmetofindout4IwasgoingtoconsumethebigboxoftofuIwasbuying.EnthusiasticallyIrepliedthatIwasbuyingfoodtocookbreakfastforhomelesspeople. WhileIwasgettingreadytopaythebilltomy5amazesheofferedtopayforeverything.Despitemultiplerequestsfor6namesherespondedthatshefeltgoodbecauseIwasdoingthekindofcommunityworkwhichherparentsoncereceivedhelpfrom7theycametothiscountryasrefugees.Henceshewantedtotake8opportunitytoshowhergratitude. Itwasthe9goodrewardIhadeverreceivedformyvoluntarywork10beganthreeyearsago.Inastrangewayweareallconnectedandwefeelgratefulforeachother.
如图是关于氧气的制取与性质实验装置图.回答下列问题 1装置中标有符号a的仪器名称是A装置用于制取氧气写出瓶中发生的化学方程式 2装置D的作用是. 3装置C中硫粉点燃后的现象是产生色火焰.
学习化学最重要的是善于用化学知识去分析解决生产生活中的问题.从化学的角度看下列说法中正确的是
Itwas难以置信的thatsuchanhonestfellowshouldhavebetrayedhisfriends.
1若核电荷数为16的元素的符号为R则粒子可用离子符号来表示R元素的原子最外层电子数为. 2铁元素是组成人体血红蛋白的重要元素市场上有含少量铁粉的营养麦片在人体胃液中与盐酸反应转化成可吸收的亚铁盐从而达到补铁的目的写出铁粉在胃液中发生的化学方程式铁元素在生成物中的化合价是.
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.错误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. DisappointingattheresultoftheexaminationIsatonthesofainsilentafterschool.MyfatherhefoundIwassounhappycometoaskmewhy.Afterlearningthereasonmyfathergavemeasmile.HesaidDon'tallowtheterriblythingsinyourlifetodiscountthepositiveones.Don'tletabaddayormonthoryeartomakeyoufeellikeyouhaveabadlifeinsteadfocusingoneverythingthat'sgoingwrongstartholdingontoallofthethingsthatisgoingright.You'llfeelbettersoon.HeardwhatmyfathersaidIfeltittheshametoactlikethatanddecidedtocheermyselfup.
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