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如图所示的温控电路中，R1为定值电阻，R2为半导体热敏电阻（温度越高电阻越小），C为电容器，电源内阻不可忽略．当环境温度降低时下列说法正确的是（ ）
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高三下学期物理《》真题及答案
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小明在科技活动中了解到有一种用半导体材料制成的热敏电阻其电阻R.随温度t变化的图像如图甲所示.1热敏
如图所示电路中R.是一个定值电阻Rl是一个半导体材料制成的热敏电阻其阻值随温度变化的曲线如图所示当开
如图所示电路中RT为热敏电阻R1和R2为定值电阻当温度升高时RT阻值变小开关S.闭合后若温度降低下列
通过R2的电流
通过RT的电流
通过R1的电流
电容器两极板间的电场强度
半导体电阻的大小随温度的变化会发生明显的改变用半导体材料制成的电阻叫热敏电阻.热敏电阻可以用来监控汽
10℃
30℃
60℃
90℃
半导体电阻的大小随温度的变化会发生明显的改变用半导体材料制成的电阻叫热敏电阻热敏电阻可以用来监控汽车
10℃
30℃
60℃
90℃
正温度系数型半导体热敏电阻的色标为绿色负温度系数型半导体热敏电阻的色标为红色临界型半导体热敏电阻的色
小明在科技活动中了解到有一种半导体材料制成的热敏电阻其电阻R.随温度t变化的图像如甲图所示1热敏电阻
如图所示的电路是一个应用非门构成的简易火警电路.则框中框中应是
为半导体热敏电阻，
为可交电阻
为半导体热敏电阻，
为开关
为可变电阻，
为半导体热敏电阻
、
均为半导体热敏电阻
某兴趣小组为了研究电子温控装置将热敏电阻R1定值电阻R2以及电压表和电流表连入如图所示电路热敏电阻的
电流表和电压表示数均变小
电流表和电压表示数均变大
电流表示数变小,电压表示数变大
电流表示数变大,电压表示数变小
如图甲所示的电路中理想变压器原副线圈匝数比为10:1原线圈接入图乙所示的不完整的正弦交流电副线圈接火
R.处出现火警时电压表示数增大
R.处出现火警时电流表示数增大
图乙中电压的有效值为220V
电压表的示数为22V
小明在科技活动中了解到有一种用半导体材料制成的热敏电阻其电阻R.随温度t变化的图像如图甲所示1热敏电
如图所示为火警报警装置的部分电路其中ε为电源电动势r为电源内阻R2是半导体热敏电阻传感器它的电阻阻值
明在科技活动中了解到有一种用半导体材料制成的热敏电阻其电阻R.随温度t变化的图像如图甲所示1热敏电阻
如图所示R.t为半导体热敏电阻其他电阻都是普通的电阻当灯泡L.的亮度变暗时说明
环境温度变高
环境温度变低
环境温度不变
都有可能
如图所示为一环境温度监控电路R1为灯泡R2为半导体材料制成的热敏电阻电阻随温度升高而变小.当环境温度
半导体电阻的大小随温度的变化会发生明显的改变用半导体材料制成的电阻叫热敏电阻.热敏电阻可以用来监控汽
10℃
30℃
60℃
90℃
如图甲所示的电路中理想变压器原副线圈匝数比为101原线圈接入图乙所示的不完整的正弦交流电副线圈接火灾
图乙中电压的有效值为220V
电压表的示数为22V
R处出现火警时电压表示数增大
R.处出现火警时电流表示数增大
如图所示是观察电阻值随温度变化情况的示意图.现把杯中的水由冷水变为热水关于欧姆表的读数变化情况正确的
如果R.为金属热电阻，读数变大，且变化非常明显
如果R.为金属热电阻，读数变小，且变化不明显
如果R.为热敏电阻（半导体材料制成），读数变化非常明显
如果R.为热敏电阻（半导体材料制成），读数变化不明显
如图甲所示为半导体材料做成的热敏电阻的阻值随温度变化的曲线图乙为用此热敏电阻RT和继电器设计的温控电
小明在科技活动中了解到有一种用半导体材料制成的热敏电阻其电阻R.随温度t变化的图象如图甲所示.1热敏
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8分Duringtherosyyearsofelementaryschool小学Ienjoyedsharingmydollsandjokeswhichallowedmetokeepmyhighsocialstatus.Iwasthequeenoftheplayground.Thencamemytweensandteensandmeangirlsandcoolkids.TheyroseintheranksnotbybeingfriendlybutbysmokingcigarettesbreakingrulesandplayingjokesonothersamongwhomIsoonfoundmyself. Popularityisawell﹣exploredsubjectinsocialpsychology.MitchPrinsteinaprofessorofclinicalpsychologysortsthepopularintotwocategoriesthelikableandthestatusseekers.Thelikables'plays﹣well﹣with﹣othersqualitiesstrengthenschoolyardfriendshipsjump﹣startinterpersonalskillsandwhentappedearlyareemployedeverafterinlifeandwork.Thenthere'sthekindofpopularitythatappearsinadolescencestatusbornofpowerandevendishonorablebehavior. EnviableasthecoolkidsmayhaveseemedDr.Prinstein'sstudiesshowunpleasantconsequences.Thosewhowerehighestinstatusinhighschoolaswellasthoseleastlikedinelementaryschoolaremostlikelytoengage从事indangerousandriskybehavior. InonestudyDr.Prinsteinexaminedthetwotypesofpopularityin235adolescentsscoringtheleastlikedthemostlikedandthehighestinstatusbasedonstudentsurveys调查研究.Wefoundthattheleastwell﹣likedteenshadbecomemoreaggressiveovertimetowardtheirclassmates.Butsohadthosewhowerehighinstatus.Itclearlyshowedthatwhilelikabilitycanleadtohealthyadjustmenthighstatushasjusttheoppositeeffectonus. Dr.Prinsteinhasalsofoundthatthequalitiesthatmadetheneighborswantyouonaplaydate﹣sharingkindnessopenness﹣carryovertolateryearsandmakeyoubetterabletorelateandconnectwithothers. InanalyzinghisandotherresearchDr.PrinsteincametoanotherconclusionNotonlyislikabilityrelatedtopositivelifeoutcomesbutitisalsoresponsibleforthoseoutcomestoo.Beinglikedcreatesopportunitiesforlearningandfornewkindsoflifeexperiencesthathelpsomebodygainanadvantagehesaid. 1Whatsortofgirlwastheauthorinherearlyyearsofelementaryschool? A.Unkind. B.Lonely. C.Generous. D.Cool. 2Whatisthesecondparagraphmainlyabout? A.Theclassificationofthepopular. B.Thecharacteristicsofadolescents. C.Theimportanceofinterpersonalskills. D.Thecausesofdishonorablebehavior. 3WhatdidDr.Prinstein'sstudyfindaboutthemostlikedkids? A.Theyappearedtobeaggressive. B.Theytendedtobemoreadaptable. C.Theyenjoyedthehigheststatus. D.Theyperformedwellacademically. 4Whatisthebesttitleforthetext? A.BeNice﹣YouWon'tFinishLast B.TheHighertheStatustheBetter C.BetheBest﹣YouCanMakeIt D.MoreSelf﹣ControlLessAggressiveness
如图ABC为固定在竖直平面内的轨道AB段为长0.75m的粗糙水平杆BC段为半径R＝2.5m圆心角θ＝10°的光滑圆弧AB相切于BC．穿在轨道上的小球在A处时速度水平向左大小为1.0m/s已知小球与AB之间的动摩擦因数μ＝0.05求g取10m/s2 1小球向左经过B点时的速度大小 2小球在圆弧上达到的最大高度 3小球从最大高度起需多长时间再次经过B点．
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30分Everyyearabout40000peopleattempttoclimbKilimanjarothehighestmountaininAfrica.They1withthemlotsofwaste.The2mightdamagethebeautyoftheplace.Theglaciers冰川aredisappearingchangingthe3ofKilimanjaro. HearingthesestoriesI'm4abouttheplace﹣otherdestinationsaredescribedaspurernaturalexperiences. HoweverIsoon5thatmuchhaschangedsincethedaysofdisturbingreportsof6amongtonsofrubbish.Ifinda7mountainwithtoiletsatcampsandalongthepaths.Theenvironmentalchallengesare8buttheeffortsmadebytheTanzaniaNationalParkAuthorityseemtobe9. ThebestofaKilimanjaro10inmyopinionisn'treachingthetop.Mountainsare11asspiritualplacesbymanycultures.This12isespeciallyevidentonKilimanjaroas13gothroughfiveecosystems生态系统inthespaceofafewkilometers.Atthebaseisarainforest.Itendsabruptlyat3000meters14landsoflowgrowingplants.Furtheruptheweather15﹣lowcloudsenvelopethemountainsideswhicharecoveredwiththickgrass.I16twelveshadesofgreenfromwhereIstand.Above4000metersisthehighland17gravel砾石stonesandrocks.18youclimbintoanarctic﹣likezonewith19snowandtheglaciersthatmaysoondisappear. DoesKilimanjaro20itsreputationasacrowdedmountainwithlinesoftouristsruiningtheatmosphereofpeace?Ifoundtheoppositetobetrue. 1A.keep B.mix C.connect D.bring 2A.stories B.buildings C.crowds D.reporters 3A.position B.age C.face D.name 4A.silent B.skeptical C.serious D.crazy 5A.discover B.argue C.decide D.advocate 6A.equipment B.grass C.camps D.stones 7A.remote B.quiet C.all D.clean 8A.new B.special C.significant D.necessary 9A.payingoff B.spreadingout C.blowingup D.fadingaway 10A.atmosphere B.experience C.experiment D.sight 11A.studied B.observed C.explored D.regarded 12A.view B.quality C.reason D.purpose 13A.scientists B.climbers C.locals D.officials 14A.holdingonto B.goingbackto C.livingupto D.givingwayto 15A.changes B.clears C.improves D.permits 16A.match B.imagine C.count D.add 17A.village B.desert C.road D.lake 18A.Obviously B.Easily C.Consequently D.Finally 19A.permanent B.little C.fresh D.artificial 20A.enjoy B.deserve C.save D.acquire
30分Paullookedoutofthewindowoftheclassroomandsighed.Thedrivewaywasstill1anditwasgettingdark.Hisdadhadsaidthathewould2himupby530butitwasalmostsevenandPaulhadn'theardawordfromhim.Paul3todosomeofhisreadinghomework.4hecouldn'thelpthinkingofhisdad.Heknewthathisdadhada5andalifebuthecouldn't6whyhewasalwaysbreakinghis7. ThenextdayatschoolPauldidn't8hismathhomework.Paul'steachernoticedhisunusually9performanceandaskedhimwhy.Pauldidn'twantto10him.Heknewthatifhestartedtalkingafloodof11wouldpourout.Hejustwantedtobealonewithhis12sohesatthere13notevenlookingattheteacher.WellPaulyoucan'thavethisthing14youup.Thesooneryougetitoffyour15thesooneryoucanheal. AsPaulwalkedhomefromschoolhe16thethingstheteacherhadtoldhim.Paulknewthathehadn't17himselfrecently.Maybehestoppeddoinghisworkbecausehewaslookingfor18fromhisfather.Herealizedthathewasn'tjustlettinghisdad19hisplansbuthewaslettinghimspoilhis20.Hedecidedtotaketheteacher'sadvice. 1A.dusty B.noisy C.empty D.leafy 2A.lift B.pick C.call D.put 3A.tried B.seemed C.preferred D.pretended 4A.Undoubtedly B.Honestly C.Thus D.However 5A.job B.problem C.qualification D.document 6A.believe B.analyse C.confirm D.understand 7A.records B.barriers C.promises D.habits 8A.turnover B.turnin C.complete D.do 9A.poor B.superior C.memorable D.strong 10A.disturb B.interrupt C.tell D.track 11A.homework B.revision C.enquiries D.emotions 12A.study B.pain C.responsibility D.sympathy 13A.quietly B.tentatively C.voluntarily D.unconditionally 14A.eat B.wake C.cheer D.ring 15A.routine B.plan C.chest D.curriculum 16A.gaveup B.reflectedon C.heardof D.dreamedabout 17A.persuaded B.encouraged C.defended D.been 18A.freedom B.expectation C.guidance D.attention 19A.abandon B.ruin C.oppose D.postpone 20A.privilege B.reputation C.life D.vacation
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25分假定你是李华美国朋友David来信说他对中国的丝绸文化以及一带一路倡议很感兴趣请给他回信要点如下 1丝绸始于新石器时代 2原料为蚕茧兼具高雅与环保 3古丝绸之路对世界文化交流的作用 4一带一路倡议将产生的深远影响. 注意1.词数100左右 2.可适当增加细节以使行文连贯. 参考词汇一带一路倡议theBeltandRoadInitiative 新石器时代NeolithicAge蚕茧cocoon
10分Ifyou'regoingabroadforcollegeyoumightbethinkingabouthowtogetyourselfasafeandcozyhomefortheyearsahead.Ofcoursedormitoriesarealwaysagoodplacetostart.butsomelargestatecollegesrequirejuniorstoliveoffcampusduetothelimitednumberofdormrooms.1. Howtofindahouse2.Ifyouarejustafreshmanordon'tknowmanypeopledon'thesitatetoapproachsomeupperclassmeninyourclassesorclubs.Moreoftenthannotupperclassmenhavemoreexperiencewithrentingandaremorefamiliarwiththeareayourschoolisin. Anothergoodideaistotalktoseniorswhoarecurrentlylivingoff﹣campus.Theseseniors'landlordswillmostlikelybelookingfornewtenants房客aftergraduation. Alsoregisteredrealtors房地产经纪人mightbeabletofindyouaplaceforafee.InadditionFacebookgroupscanalsoprovidesomeusefulinformation.3. Roommates Havingroommatescannotonlysaveussomemoneybutalsogiveusvaluablecom﹣panionship.Howeverrememberthatfindingtherightroommatesforyouisthemostimportantthingotherthansafetyconcerns.4definitelydonotlieaboutyourpreferencesscheduleorhabitseveniftalkingaboutthemcouldmakeyouuncomfortable.Ontheothersidealsoremembertoaskyourpotentialroommatestotellyouaboutthemselvesindetail. 5pleasedoeverybodyafavorbybeingupfrontaboutit.Constantlyrunninginto conflictswithyourquietroommateisdefinitelythelastthingyouwant. A.Ifyouareapartyanimal B.Whilelookingforroommates C.Getalongwellwithyourroommates D.Whenhavingachatwithyourroommate E.Firstyoucanaskyourfriendswhoarealreadylivingoffcampus F.Howeverbereallycarefulifyougetintouchwithstrangersthroughtheinternet G.Nonethelessrentinganapartmentcangiveyousomehands﹣onexperiencewithliving
VisitorsstillstopattheoldhouseinScituateMassachusetts.Butthehouseisnotwhatbringsthemthere.Whattheywanttoseeistheoldstonewellbesideit﹣andtheiron﹣boundwaterbucketthat'sputonitsedge. TwohundredyearsagothisfarmhousewasthehomeofSamuelWoodworth.DuringthelongsummersofhischildhoodyoungSamuelwouldoftenpauseatthewell.Itwasawelcomebreakespeciallyonahotafternoon.Onsuchadayhewouldeagerlydrawabucketfulofcoldwaterandsatisfyhisthirstwitharefreshingdrink. WhenhewasfourteenWoodworthleftScituateforNewYorkCitywherehestartedhisownnewspaper.Laterheworkedasaneditoratothernewspapersandmagazineswhilewritingnovelsplaysandpoetryinhissparetime.Hislifewasbusyandherarelyhadtimetovisitthefamilyfarm. ButWoodworthneverstoppedthinkingofhisScituatehome.AfterworkoneeveningWoodworthpouredhimselfaglassofcitywater.AfterthatheremarkedtohiswifeLydiahowwonderfulitwouldbetohavealongcooldrinkfromtheoakenbucketathisfather'swell.LydiahadasuggestionWhynotputittopoetry? ItwasasuggestionWoodworthcouldnotresist.ThatnighthewroteTheBucket.Inithecapturedtheworldofhischildhoodonahotsummerdayandthesimplejoyofstoppingforadrinkathisfather'swell. Hispoemwasaninstantsuccess.Itseemedtotoucheveryonewhohadeverbeenhomesick.AttheheightofitspopularityTheOldOakenBucketasitcametobecalledwastranslatedintofourlanguagesandthewordsweresettoapopulartuneofthetime.OvertheyearscountlesspeoplehavereadorsungWoodworth'sodetohisboyhood.TodayitistheofficialsongofScituateMassachusetts. 1Whydoestheauthoruseflashback倒叙inParagraph2? A.Tohelpreadersappreciatethewellwater. B.Tohelpreadersenjoycitylife. C.TohelpreadersunderstandhowhardWoodworthwas. D.TohelpreaderslearnaboutWoodworth'schildhoodlife. 2WhatwasWoodworth'spurposeforwritingthepoem? A.Tosharehisopinion. B.Tointroducehishometown. C.Toexpresshisemotion. D.Tomakesomecomplaints. 3Whatcanweinferfromthetext? A.Thewaterinthewelltastedbetterthanthatinthecity. B.ThewellandthewaterhadadeepimpressiononSamuel'smind. C.Woodworth'swiferemindedhimofthewellandsuggestedputtingittopoetry. D.Notmanypeoplepaidmuchattentiontothepoematfirst. 4Whichofthefollowingcanbethebesttitleforthetext? A.TheOldOakenBucket B.LivinginNewYork C.GrowingupontheFarm D.GoodSuggestionsfromWife
一列向右传播的简谐横波某时刻波形如图．已知波速为8m/s从这一时刻起经过1.75s质点M通过的路程是cm波的传播距离是m．
原子核是由质子和中子组成的它们统称为．核电站是利用选填“重核裂变”“轻核聚变”或“化学反应”获得核能并将其转为电能．
宇航员的航天服内充有气体若出舱前航天服内气体压强为p体积为V到达太空后气体体积变为2V温度不变此时航天服内的气体压强为．1965年3月18日苏联航天员列昂诺夫在返回飞船时遇到了意想不到的困难他的航天服有些向外膨胀很难从密封舱的接口处钻回舱内他启动了应急装置减小航天服的体积安全地回到密封舱内．你认为该应急装置可以如何减小航天服体积．
用手握住较长软绳的一端连续上下抖动形成一列简谐横波．某一时刻的波形如图所示绳上ab两质点均处于波峰位置．则
甲乙两个弹簧振子它们的振动图象如图所示则可知两弹簧振子
Whyshouldmankindexplorespace?Whyshouldmoneytimeandeffortbespentexploringandresearchingsomethingwithsofewapparentbenefits?WhyshouldresourcesbespentonspaceratherthanonconditionsandpeopleonEarth?Thesearequestionsthatunderstandablyareveryoftenasked. Perhapsthebestanswerliesinourgeneticmakeupashumanbeings.Whatdroveourancestorstomovefromthetreesintotheplainsandonintoallpossibleareasandenvironments?Thewiderthespreadofaspeciesthebetteritschanceofsurvival.Perhapsthebestreasonforexploringspaceisthisgenetictendencytoexpandwhereverpossible. Nearlyeverysuccessfulcivilizationhasexploredbecausebydoingsoanydangersinsurroundingareascanbeidentifiedandpreparedfor.Withoutknowledgewemaybecompletelydestroyedbythedanger.Withknowledgewecanlessenitseffects. Explorationalsoallowsmineralsandotherpotentialresourcestobefound.Evenifwehavenoimmediateneedofthemtheywillperhapsbeusefullater.Resourcesmaybemorethanphysicalpossessions.Knowledgeortechniqueshavebeenacquiredthroughexploration.Thetechniquesmayhavemedicalapplicationswhichcanimprovethelengthorqualityofourlives.Wehavealreadybenefitedfromotherspin﹣offsincludingimprovementsinearthquakepredictioninsatellitesforweatherforecastingandincommunicationssystems.Evennon﹣stickpansandmirroredsunglassesareby﹣productsoftechnologicaldevelopmentsinthespaceindustry! Whilemanyresourcesarespentonwhatseemsasmallreturntheexplorationofspaceallowscreativebraveandintelligentmembersofourspeciestofocusonwhatmayservetosaveus.Whilespacemayholdmanywondersandexplanationsofhowtheuniversewasformedorhowitworksitalsoholdsdangers.Thedangerexistsbutknowledgecanhelphumanbeingstosurvive.Withouttheabilitytoreachoutacrossspacethechancetosaveourselvesmightnotexist. WhileEarthistheonlyplanetknowntosupportlifesurelytheadaptiveabilityofhumanswouldallowustoliveonotherplanets.Itistruethatthelifestylewouldbedifferentbuthumanlifeandcultureshaveadaptedinthepastandsurelycouldinthefuture. 1Whydoestheauthormentionthequestions? A.Toexpresshisdoubts. B.Tocomparedifferentideas. C.Tointroducepointsfordiscussion. D.TodescribetheconditionsonEarth. 2Whatisthereasonforexploringspacebasedon? A.Humansarenatureborntodoso. B.Humanshavethetendencytofight. C.Humansmayfindnewsourcesoffood. D.Humansdon'tliketostayinthesameplace. 3Theunderlinedwordspin﹣offsinParagraph4probablyrefersto. A.survivalchances B.unexpectedbenefits C.potentialresources D.physicalpossessions 4Whichofthestatementscanbestsumupthepassage? A.Spaceexplorationhascreatedmanywonders. B.Spaceexplorationprovidesthebestvalueformoney. C.Spaceexplorationcanbenefitscienceandtechnology. D.SpaceexplorationmayhelpusavoidpotentialproblemsonEarth.
15分LastyearmybrotherandIwenttoMiamiforavacation.Someofmyfriendswhohadbeentherebeforesaiditwas1wonderfulholidaydestination.Beforewewentwehadplannedformonths.Whenthedaycamewewereready. Sinceitwasthefirsttimewe2betherewewereprettyexcited.Afterourplanelandedwewenttothehotel.Wehadmade3wereservationsixmonths4earlybutthemanatthefrontdesksaidtherehadbeenamistake.We5tellthatourroomshadn'tbeenreservedforthatweek6fortheweekafter.Ididn'tunderstandwhythiswouldhappenandmycreditcardhadalreadybeenchargedforthereservation.What'sworsethehotelhadbeenfullybooked.Whenwe7wonderwhattodothemanagercameout.Shewas8surprisehelpful.SheapologizedforthemistakeandgaveusaspareVIProomonthetopfloor.Wehadneverstayedinsuchanamazingroomandweweren'tchargedextra. ThenextdaymybrotherandIwenttothebeach9somepeoplewereplayingvolleyball.Wegotalittle10sunburnbutthedayhadbeensorelaxingthatwedidn'tmind.
磁体的磁感线是
8分It'satthistimeoftheyearthatmarathonrecoverynotmarathontrainingstartstotakecenterstage. Researchindicatesthatthemuscledamagefromrunningamarathoncanlastuptotwoweeks.Theresearchalsoindicatesthatmusclesoreness肌肉酸痛isnotagoodindicatorofmuscularhealing.Inotherwordsjustbecauseyouaren'tsoreanymoredoesn'tmeanthatyouarefullyhealed.Thisisthedangerformarathonrunnerspost﹣marathonmuscularsorenessfadesafterafewdaysbutminordamagewithinthemusclecellsremains.Ifyoureturntofulltrainingtoosoon﹣runningmoreandfasterthanthetissuesarereadyfor﹣youriskdelayingfullrecoveryandthechancetogetreadyforyournextgoal. Thesolutionitappearsistorecognizeandacceptthatthemuscleswilltakeawhiletohealandtobepreparedtotakeiteasyforthefirstcoupleofweeksevenlongerifyou'reparticularlysoreafteryourmarathon.Whiletheresearchisn'tverypromisingwhenitcomestothingstodotoreducesorenessandaidhealingacoupleofconceptsappeartohelp.Firstprovidinggentlebloodflowtotheareahelpsbringhealingnutrientsintothemusclesandalsohelpstoremovewasteproductsanddamagedtissue.Walkingandgentlemassage按摩canhelpparticularlyinthefirstfewdaysafteramarathon.Oncemusclesorenesshassignificantlyreducedusuallytwotofourdaysaftertheracelightjoggingcancommence.Justbemindfultorunveryslowly. Norunnerwantstogetsuperfitandthenlosethatduringtherecoveryprocess.Butsinceyoumustreduceyourtrainingloadfollowingyourmarathonitcanbedifficultastohowmuchandhowsoontoinsertrunningintoyourpost﹣marathontraining. 1Whenshouldmarathonrunnersreturntofulltraining? A.Abouthalfamonthafterthecompetition. B.Afewdaysaftersorenessdisappears. C.Beforethetissuesrecovercompletely. D.Beforethenextgamedrawscloser. 2Howcanmarathonrunnersreducetheirmusclesoreness? A.Throughfamilycare. B.Bydoinggentleexercise. C.Throughmedicaltreatment. D.Byremovingdamagedtissue. 3Whichofthefollowingbestexplainscommenceunderlinedinparagraph3? A.Fit. B.Heal. C.Start. D.Mend. 4Whatcanbeasuitabletitleforthetext? A.RecoveryafterMarathon B.SorenesswithSports C.HealingMuscleSoreness D.ReducingTrainingLoad
电场强度定义式为E＝也可用类似的方法来描述地球产生的引力场中某点的场的强弱．已知地球质量为M半径为R地表处重力加速度为g引力常量为G一质量为m的物体位于距地心2R处的某点则该点处引力场强度为
太阳是一颗自己能发光发热的气体星球它的能量来自于反应．行星在太阳的引力作用下几乎在同一平面内绕太阳公转距离太阳越近的行星公转周期大小越．
图甲是沙摆装置细沙均匀漏出同时匀速拉动纸板．图乙是细沙在纸板上形成的曲线其粗细不均匀主要是因为沙漏从最高点摆动到最低点的过程中
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