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下列福州传统工艺制作步骤中，主要发生化学变化的是（ ）
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有浓盐酸浓硫酸氢氧化钠石灰水四种物质的溶液长期存放在空气中溶液质量因发生化学变化而减少的物质是___
宣纸是中国文房四宝之一其制作工艺被列入我国首批非物质文化遗产名录下列关于宣纸的传统制作工序中主要发生
挑选原料
加碱燕煮
竹帘捞纸
剪裁纸张
蜡烛在空气里燃烧发生的变化是
只发生物理变化
只发生化学变化
只是状态发生了变化
既发生物理变化又发生化学变化
下列食品调味品的制作过程中没有发生化学变化的是
鲜奶制酸奶
黄豆酿酱油
糯米酿甜酒
水果榨果汁
蜡烛在空气中燃烧下列叙述不正确的是
有氧气参加的反应
只发生化学变化
既发生物理变化又发生化学变化
生成两种新物质
宣纸是中国文房四宝之一其制作工艺被列入我国首批非物质文化遗产名录下列关于宣纸的传统制作工序中主要发生
挑选原料
加碱腌煮
竹帘捞纸
剪裁纸张
下列说法你认为错误的是
化学变化和化学反应时同一个
物质发生化学变化时一定同时发生物理变化
化学变化的特征就是一定有沉淀生成
物质发生物理变化时不一定发生化学变化
宜纸是中国文房四宝之一下列关于其传统制作工序中主要发生化学变化的是
挑选原料
加碱腌煮
竹帘捞纸
剪裁纸张
热塑性材料在成型过程中主要发生化学变化
明德馆进入明德馆桌上的纸墨笔砚映入眼帘1下列关于宣纸的传统制作工艺中主要发生化学变化的是填字母A.粉
加氢改质装置发生化学变化的工艺是
吸附
解吸
加氢分馏
加氢反应
民以食为天厨师的下列工艺发生化学变化的是
拉面条
切南瓜
把一条鲤鱼烹饪成万州烤鱼
洗菜
以下家庭食品制作中发生化学变化的是
萝卜风干
凉水冻冰
葡萄酿酒
辣椒剁碎
下列关于酶的叙述正确的是
能使底物发生化学变化，本身也发生化学变化
其化学本质大多数是RNA，少数是蛋白质
酶在代谢中提供能量
酶大多数能被蛋白酶水解
化学与生活息息相关下列过程主要发生化学变化的是
淘米
洗菜
柠檬榨汁
葡萄酿酒
宣纸是中国文房四宝之一其制作工艺被列入我国首批非物质文化遗产名录下列关于宣纸的传统制作工序中主要发生
挑选原料
加碱燕煮
竹帘捞纸
剪裁纸张
下列食品调味品的制作过程中没有发生化学变化的是
鲜奶制酸奶
黄豆酿酱油
糯米酿甜酒
水果榨果汁
化学与生活息息相关.下列过程主要发生化学变化的是
淘米
洗菜
柠檬榨汁
葡萄酿酒
下列说法正确的是
空气是一种化合物
空气是几种单质的混合物
发生物理变化必定发生化学变化
发生化学变化必定发生物理变化
净化水的措施较多有些措施发生化学变化我认为下列净化水的措施中一定发生化学变化的是
用活性炭吸附
过滤
用漂白粉消毒
蒸馏
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正是为了人民的利益一些政府官员抵制金钱和权力的__将经济改革进行到底.It.
如图一个重力为10N的物块以20m/s的速度冲上了高为5m长为10m的光滑斜面达到斜面顶端时物块的速度恰好减小为0．对此过程以下分析正确的是
Talkingtohuman﹣likedevicescanbegreatfun﹣justaskSiritotellyouajoke.Butitmuyalsoleadtoproblems. ArecentstudybyscientistsfromtheUniversityofKansasintheUSfoundthathuman﹣likedeviceskeeppeoplefromseekingoutnormalhumaninteractionwhentheyfeellonely. Duringaseriesofexperimentspanicipantswereaskedtowriteaboutatimewhentheyfeltlonely.Theyalsotookpartinanonlinegameofcatchagainstacomputerprogramthatwasdesignedtothrowthehalltootherplayersmoreoftenbutparticipantsbelievedtheywereplayingwithrealpeopleonline. Participantswerethenintroducedtohuman﹣likeproductsincludingavacuumcleaner真空吸尘器designedtoappearasifitweresmiling.Theywerealsoaskedtothinkabouttheirphoneinhuman﹣liketermsconsideringquestionslikehowmuchdoesithelpyou Theresultsshowedthattheparticipantswerehappywiththecomforttheygotfromthemachinesanddidn'tneedtoseekoutnormalhumaninteraction. Generallywhenpeoplefeelsociallyexcludedtheyseekoutotherwaystoreduce thefeelingofloneliness.NormalwaysincludeincreasingtheirnumberofsocialmediafriendsorengaginginbehaviorstoseekoutinteractionwithotherpeopleaccordingtoJennyOlsonassistantprofessorofmarketingatKU. Butitwasn'tallbadnewsastheteamfoundthattherewerelimitstohowfarthiseffectwouldextend. Assoonaswetellpeopleweknowthatitlookslikethevacuumcleanerissmilingtheyseemedtorealizeitwasamachineandnotaperson.OlsontoldDailyMail.Theeffectgoesaway.Thisseemstobehappeningonaverysubconsciouslevel. Researchersbelievetheresultsarcimportantforconsumerstorealizehowthesetypesofproductscouldaffecttheirsocialinteractionwithrealpeopleespeciallybecausesomanynewproductsfeatureinteractivity. lfsomeonenoticestheyaretalkingmoretoSirilatelymaybethathassomethingtodowithfeelinglonely.Olsonsaid.Fromthatstandpointit'simportanttobeawareofit. Thestudycouldalsohelpcompaniesdesignproductsthatcanincreasethewell﹣beingofpeoplewhofeellonelywithoutsacrificingnormalsocialinteraction. Maybeiiismoreaboutimprovingourcurrentrelationships.Olsonsaidsuchastakingabreakfromscreentimeandfocusingondevelopingyourrealpersonalconnections. 56.ResearchersfromtheUniversityofKansasfoundthat. A.hunum﹣likedevicesmayhelppeopleinteractwithothers B.interactionswithhuman﹣likedevicesmaymakepeoplefeellonely C.lonelypeoplemayeasilybecomeaddictedtohuman﹣likedevices D.human﹣likedevicesmayreducepeople'ssocialinteractioninreallife 57.Duringtheexperimentsparticipants. A.wereallowedtotalkwithhuman﹣likedevices B.wereshowndeviceswithhumanfeatures C.playedonlinegameswithbothmachinesandrealpeople D.wereencouragedtoengageinnormalhumaninteraction 58.TheunderlinedphrasethiseffectinParagraph7referstothefactthat A.lonelypeoplearemorelikelytoseekoutinteractionwithotherpeople B.lonelypeoplearecontenttointeractvviihhuman﹣likemachines C.thefeelingoflonelinessdeepensaspeopleinteractwithhuman﹣likedevices D.peoplewhoaresociallyexcludedwillhavedifficultyinsocializing 59.Oneofthesignificancesofthestudyisthatit. A.showspeoplewhyhuman﹣likeproductsmakethemfeellonely B.warnspeopletoabandonhuman﹣likedevicescompletely C.forceslonelypeopletogetinvolvedinnormalsocialinteraction D.helpcompaniesrealizethelimitationofhuman﹣likedevices.
AstudybySanDiegoZooGlobalconservationistsreleasedthisweekSept.122016issheddingnewlightonhowscientistsevaluatepolarbeardietandweightlossduringtheirfasting禁食season.Onaverageapolarbearlosesupto30percentofitstotalbodymass体重whilefastingduringtheopen﹣waterseason.Althoughsomescientistspreviouslybelievedland﹣basedfoodscouldsupplement补充thebears'nutritionalneedsuntiltheseaicereturnsanewstudypublishedinthescientificjournalPhysiologicalandBiochemicalZoologyhasrevealedthataccesstoterrestrialfoodisnotsufficienttoreducetherateofbodymasslossforfastingpolarbears. Thestudy﹣﹣undertakenbyManitobaSustainableDevelopmenttheUniversityofAlbertaandEnvironmentandClimateChangeCanada﹣﹣weighedpolarbearsthatweredetainedinthePolarBearHoldingFacilityinChurchillManitobaCanadafrom2009to2014.PolarbearswerekeptinthisfacilityaspartofthePolarBearAlertProgramwhichaimstoreduceconflictbetweenhumansandpolarbearsaroundthetownofChurchill.Topreventhabituationpolarbearsarenotfedwhileinthefacilitywhichallowedforacontrolledmeasureoftheirweightloss.Onaveragepolarbearslost2.2pounds1kilogramofmassperday﹣﹣exactlythesameamountasfree﹣ranging自由放养的bearsmeasuredduringtheice﹣freeseasononthecoastlineofHudsonBay.Scientistsreportedthatevenwithland﹣basedfoodopportunitiespolarbearslostthesameamountofweight. Somestudieshavesuggestedthatpolarbearscouldadapttoland﹣basedfoodstooffsetthemissingcaloriesduringashortenedhuntingperiodontheicesaidNicholasPilfoldPh.D.leadauthorofthestudyandapostdoctoralassociateinAppliedAnimalEcologyatSanDiegoZooGlobal.Yetourresultscontradictthisasunfedpolarbearsinourstudylostmassatthesamerateasfree﹣rangingbearsthathadaccesstoland﹣basedfood. Researchersalsoestimatedstarvationtimelinesforadultmalesandsubadultsandfoundthatsubadultsweremorelikelytostarvebeforetheiradultcounterparts.SubadultpolarbearshavelowerfatstoresandtheaddedenergydemandsassociatedwithgrowthsaidPilfoldFuturereductionstoon﹣icehuntingopportunitiesduetoseaicelosswillaffecttheyoungerpolarbearsfirst﹣﹣especiallygiventhatthesebearsareless﹣experiencedhunters. 63.Whatisthefindingofthisnewly﹣releasedstudy A.Wildpolarbearsarefacingthedangerofstarvationandextinction. B.Land﹣basedfoodcan'tmeetthenutritionalneedsofwildpolarears. C.Wildpolarbearscanavoidweightlossinaproperlydesignedfacility. D.Traditionalwaystomeasurepolarbeardietandweightlossarenotaccurate. 64.WhichofthefollowingisTRUEaboutthestudy A.ItwasactuallypartofthePolarBearAlertProgram. B.Itaimedtopreventthepolarwildlifefromextinction. C.Itcomparedtheweightlossbetweenunfedandfree﹣rangingpolarbears. D.ltmeasuredtheweightofpolarbearsduringon﹣icehuntingseasons. 65.Theunderlinedwordinthefourthparagraphmeans. A.takeover B.takeup C.makeinto D.makeupfor 66.Thereasonswhysubadultsaremorelikelytosufferduringopen﹣waterseasoninclude. Theyhavelessfatstorage. Theyneedmoreenergyforgrowth. Theylackhuntingopportunities. Theyareslowerinadaptingtoiceloss. A.①②B.③④C.①②③D.②③④
下列相关的量之间的关系符合如图所示图线的是
如图圆柱形盛水容器横截面积为S1．重力为G的柱形金属块横截面积为S2已知S1＞S2金属块用细线悬挂并使之底面恰好与水面齐平．现将金属块缓慢下降浸入水中设水均不溢出且金属块不浸没水的密度为ρ则 1金属块底面在水中深度为h时金属块所受浮力为多少 2金属块相对容器底部下降高度为H时盛水容器底部增大的压强是多少
教室内的日光灯一般都是由两条竖直平行的吊链吊在天花板上的图甲所示两条吊链竖直平行除了美观外还蕴含着科学道理． 1甲图中ab是挂日光灯的吊链．若以吊链a的固定点O作为支点F甲作为拉力时可将灯视作杠杆．选填“省力”“费力”或“等臂”． 2比较甲图乙图两种悬挂方式甲图吊链受到的拉力大小为F甲乙图吊链受到的拉力大小为F乙则F甲F乙选填“＞”“＝”或“＜”． 3若甲图中b吊链突然断开后日光灯将绕O点转动此时日光灯的重力势能将．选填“增大”“减小”或“不变”．
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随着物联网技术的发展智能家居已悄然走向前台．下图为智能家居中的安防系统和饮用水净化系统请回答问题 1安防系统 门禁系统智能家居的门禁系统倾向于利用生物识别如指纹锁等．不同的人指纹不同指纹是人的一种性状由决定．烟雾报警图1是烟雾报警器的简化原理图其中电源电压恒定不变R0为定值电阻R为光敏电阻当有烟雾遮挡射向光敏电阻的激光时电路中的电流减小到某一数值时报警器开始报警．则光敏电阻的阻值随光照强度的减弱而选填“增大”“减小”或“不变”此时电压表示数较未报警前选填 “增大”“减小”或“不变”． 2饮用水净化系统 如图2所示在饮用水净化系统中设备①②③的作用分别是．
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假定你是李华你的美国交换生同学Amber想去参加市博物馆的外籍志愿讲解员选拔活动发邮件向你征求意见.请你回复邮件内容包括 1.表示支持并说明理由 2.参选前需要做的准备. 注意 1.词数100左右 2.可以适当增加细节以使行文连贯. 参考词汇讲解员docent
在科学实验中常用到斜面这一简单机械请回答问题 1利用斜面研究阻力对物体运动的影响如图甲所示．小车从同一斜面的同一高度由静止开始滑下在毛巾木板平板玻璃等不同的表面上前进不同的距离后停止此过程中小车克服阻力做功．假设在毛巾木板平板玻璃表面上小车克服阻力做的功分别为W1W2W3请比较并写出它们的大小关系式． 2利用斜面探究动能大小与哪些因素有关如图乙所示．在这个实验中通过观察比较来判断小球动能的大小．要探究动能大小与物体的运动速度应该如何操作．
如图所示用10N的力F沿水平方向拉滑轮可使物体A以0.2m/s的速度在水平面上匀速运动．弹簧测力计的示数恒为2N不计滑轮测力计绳子的重力滑轮的转轴光滑．下列说法正确的是
Agrouptripismuchmoredifferentthanwhatonemightexpectwithanorganizedtourorasoloholiday.1Thusitiscertainlyanexperiencetoenjoy. Goingonholidaywithagroupoffriendsisallabouthavingfuncreatingmemoriesandtryinganewexperiencewithasharedinteresttotravel.2Italsohelpsyoulearnmoreabouthowtotravel.Whetheryoudecidetogoinalargegroupofupto10peopleormoreorgoinamuchsmallergroupof4grouptripsareagreatwaytobondandreconnectwithoneanother.3Itcanhappenperiodicallyperhapsonceortwiceayear. Planningagrouptripmaybedifficultbuttheresultwillbesatisfying.Chooseapopularlyknowndestinationoranunknowndestination.Thisdecisioncanactuallysetthefoundationforthemoodofthetrip.4Thiswillgivegroupmembersanideaofwhattheycanexpectforthenextgrouptrip. Thepurposeofthegrouptripforsomemaybetoescapefromthecityortheircurrentbusyschedules.5Whethertheywillbepositiveornegativememoriesthemainideaisthatasagrouptheywillbeabletolinktheirtriptothememoriescreated. A.Besidesitdoesn'thavetobeaconstantactivity. B.Youwillonlyenjoysuchatriponceinalifetime. C.Itmeansbeinginsidejokesgreatstoriesandplentyoflaughs. D.It'sspecialbothinitsformandtheuniqueexperienceitoffers. E.Forothersitmaybetocatchupwithfriendsoveraperiodoftime. F.Theyhavebeenalonefortoolongatimeandthusbadlyneedatrip. G.Youwillexperienceneworfamiliardestimationswithcloseacquaintances.
下列食物中富含蛋白质的是
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Onetrendinappdevelopmentispositivityprogramsdesignedspecificallytohelpretrainourbraintothinkpositively.Hereareourtoprecommendationsforappstoimproveyourpositivemood. ThinkUp Havinga4.7starratingthisappisaheavyhitterintheworldofpositivityapps. Peoplearefindingthattheycanlearntobepositiveandsavetheirlivesfromtheconvenienceoftheirhandhelddevices设备.Wenolongerhavetogotothelibraryandcheckoutbooks.Justdownloadthisfreeappandstartthinkingpositivelyandwatchhowyourlifechanges. Shine Thisappisrecognizedasthebestof2018andithelpsyouwithdailymotivationandpersonalcare.Thisapp'sgoalistohelpreduceyourstresssodon'tworryaboutaddingonemorethingtoyourto﹣dolist.Theysendmotivationaltextsincludingagratitudejournal.Thisisanincrediblewaytechnologyjoinsgreatmindssowecanallimprovetogether! Happler Holdingastrong3.9starevaluationgradethisisonewelove.Itcanhelpyoukeepajournalhasincrediblecoursesandletsyouexchangeideaswithawholecommunityofpeopleworkingtobecomemorepositive.Welovethecreativitythatwentintomakingthisappandthinkithasalottooffer. Motivate Thisappgainsa4.8starratingafterover2622ratingswhichhashandpickedmotivationvideosandmusicplaylistsforanymoodyou'dliketogetinto.Ifyouneedtorelaxorgetenergizedorinspiredtogrowinspecificareasofyourlifethisuniqueappwillhelpyouchooseyourcategoryandgetyouthinkingpositivelyaboutitthroughtheuseofimagesandmusic. 1Whichcanhelpyouwithpersonalcare? A.ThinkUp. B.Shine. C.Happier. D.Motivate. 2Whatdothefourappshaveincommon? A.Theyofferinteractiveteaching. B.Theyenableuserstobemorepositive. C.Theyareallstar﹣rated. D.Theyhelppeoplereachtheirgoals. 3What'sspecialabouttheappMotivate? A.Itgainsthehighestrating. B.Ithelpspeoplekeepajournal. C.Itprovidesvideosandmusic. D.Itsendsmotivationaltexts.
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InanewstudypublishedinjournalJAMAPaediatricsresearchersfoundtheamountoftimethatchildrenundertheageoftwospendlookingatscreensondigitaldeviceshasmorethandoubledovera17﹣yearperiod. Theteamtookalookbackatatimewhenmobilephoneusewasfarlesscommonthanitistodayassessingchildren'sscreentimein1997andthencomparingitto2014. TheresearchersusedstatisticspreviouslygatheredbytheChildDevelopmentSupplementPanelStudyofIncomeDynamicsattheUniversityofMichigananalysingdataregarding1327childrenin1997and443childrenin2014. AccordingtotheirfindingschildrenundertheageoftwointheUSwouldspendanaverageof1.32hoursinfrontofascreenonadailybasisin1997.By2014thisaveragehadincreasedto3.05hoursmorethandoublingover17years.Incomparisonchildrenagedbetweenthreeandfivespentanaverageoftwoandahalfhoursinfrontofscreensonadailybasisin1997.Thishadincreasedslightlytothreehoursadayby2014. ThereisgrowingconcernovertheamountoftimethatchildrenparticularlyveryyoungchildrenspendwatchingshowsandinfrontofscreenssaidWeiweiChenassistantprofessorintheDepartmentofHealthPolicyandManagement.Ourfindingsweresurprisingasitfeelslikemobiledevicesareeverywherebuttelevisionsarestillthemostcommonwayforyoungchildrentoconsumemedia.Furtherresearchisneededtoassesschangesinmediaconsumptionanddeviceuseinmorerecentyears. Expertswarnedthatvulnerablechildrencouldfacebecominglostindigitalspaceasthey'regrowingupwithoutenoughInternetsafetyeducation. 1Whatcanweknowaboutthenewstudy? A.Ittook17yearstoconduct. B.Itincludedchildrenbornin1997. C.Itcomparedstatisticsfromtwodifferentperiods. D.Itwasdonebytwoorganizationsworkingtogether. 2Howdidthedailyscreentimeofchildrenbetween3and5change? A.Italmostdoubled. B.Itreducedslightly. C.Itreached2.5hours. D.Itsawasmallchange. 3Whatsurprisedtheresearchers? A.ChildrenspentmoretimeonTVthanonmobiledevices. B.Digitaldevicesgainedmorepopularityamongchildren. C.Childrenstaredatscreensformuchlongerthanbefore. D.Digitaldevicesfailedtoattractyoungchildren. 4Whatisthebesttitleforthetext? A.ScreenTimeDamagesChildren'sHealth B.NewMethodsFoundtoReduceScreenTime C.ParentsInstructedtoLimitChildren'sScreenTime D.ChildrenunderTwoSpendTwiceLongeronScreens
学校举行运动会小明同学在跳远运动的几个阶段如图所示则他
Chinesedragons龙arefictionalcreaturesarootofChinesepeoplewhoconsideredthemselvesasthedescendants后代ofdragons.SincetheircreationChinesedragons1winthedeeplovefromChinesepeoplebecauseof2theystrongpowerandsymbolicmeanings.Theyplayed3importantroleinthehistoryofChinesenationpoliticsreligioncultureandChineselanguageandbecameasymbolofChinaandChinesepeople. DragonisabeliefofChinesenationanda4goldChineseelement元素.WhenapersonhearsthenameofdragonChina5cometohisorhermind.Asthestrongestanimal6selectbyChinesepeopledragonhasthestrongestpower7helpsitgototheHeavenandtheHellandmakecloudandrains.Inancienttimesasabeliefdragongavestrongsupportstotherulingofabignationandtopeople'sfragilespiritsandhardlifebecausepeoplesufferedfromextremenaturaldisastersandlack8thesupportsfromscience.The9importantofdragontoChinesepeopleislikewatertocreaturesandit10reflectinpeople'sspiritbeliefsandideology.
下列是生活中一些常见物质的近似pH其中酸性最强的是
小乐利用长宽和厚度均相同的锌片铁片与铜片完成了以下实验 利用锌片和铜片制作电池 1小乐从课本中得知将一块锌片和一块铜片插入稀硫酸就可以组成一个电池铜片和锌片是电池的两个电极且溶液中部分离子移动的方向和电极上电子移动的方向如图乙所示．此电池的能量转化是若要用电压表测此电池的电压则电压表的负接线柱应与相连选填“铜片”或“锌片” 2小乐从课本中还知道若在水果中插入锌片和铜片可以制得水果电池于是她完成了 如下实验 通过上述实验可知水果电池电压大小的影响因素有．
易拉罐拉环拉断后就很难打开若将A4纸对折几次后用纸的硬尖角摩擦原拉环边缘如图所示一会儿罐口就会自动冲开并看到一团“白汽”．出现这团“白汽”是因为水蒸气发生了选填“液化”或“汽化”现象．摩擦后罐口会自动冲开是因为罐内气体对罐口拉片压力增大使罐口打开．
A.changingB.availableC.exposureD.worsenE.sensitive F.densityG.restH.shadedI.refleciionsJ.interruptedK.fighting Areyoureyesdrywateryseeingdoubleor31tolightanddoyourbackandneckacheIfsoyouarelikelyoneofmanypeopletodaywhosufferfromdigitaleyestrain视疲劳alsocalledcomputer﹣visionsyndrome. Eyestrainisoftenrelatedtotheamountof32toscreensthedistancefromeyestoscreensandtheuseofmultiplescreensatthesametime.Howeverstudies havealsoshownthatthebluelightproducedbydigitaldevicesreachesfurtherintotheeyesthanotherkindsoflight.Thislightactuallyassisisattentionduringthedaybutcanresultin33sleeppatternsatnight. Scientistshavestatedthateyestrainisnotanecessaryevileveninamodernworldthatcirclesaroundtechnology.Sometimes34somesimpledetailsaboutyourrelativepositiontoscreenssuchasslayingabout60centimetersawaywillhelp.Alsoavoidoverheadandotherdirectsourcesoflightanduse35lampsandwindowblindswhilelookingatdigitaldevicesinstead. Beyondthewaysthatyourelatetodigitalscreenstherearealsowaystochangehowyouviewscreensthatarehelpfulin36eyestrain.Tobeginwithyourcomputerscreenshouldbehigh﹣resolution高分辨率andmayrequireascreentodecrease37.Alsobeawarethat''computerglasseswhichcutdownglare刺眼的光}andbluelightare38onthemarkect. Finallymanyofusfallintobadhabitswhileusiugdigitalscreensthatonly39theeffectsofeyestrain.Whenviewingdigitalscreensmanypeopleblink眨眼onethirdlessoftenthantheyusuallydo.Placeareminderonyourcomputertoblink!sothatyoureyesdon'tdryout.Also40youreyes'focusingmusclesbyusingthe20﹣20﹣20ruleevery20minutesfocusonsomething20feetawayfor20seconds. Therearemanyothermethodsusedtohelprelieveeyestrainsofindwhatworksforyouratherthangivingintotiredvision.
WiththeaveragenumberofchildreninaBritishfamilyfallingunderanaverageof2.0comparedwiththetraditional2.4childrenthepopulationoftheUKhasbeenfallingforquiteafewyears. Whyaren'tBritishpeoplehavingasmanychildrenastheyusedtoWelltherearemanyreasons.OneofthemisthatBritishpeoplearenowhavingtheirchildrenatamucholderagethanpreviouslymeaningtheyhavefeweryearsinwhichtheycanhavechildren.Mostyoungpeopletodaywantawell﹣paidjobsotheyoftengotouniversityafterhighschoolafteryearsofstudyatuniversitytheythenneedafewyearsofworkexperiencebeforetheycangetthejobtheywant.Soit'snotuntiltheyareabout30yearsoldthattheycanstarttothinkaboutsettlingdownandhavingchildren. AnotherreasonisthatitisrelativelyexpensivetobringupachildintheUK.Usuallybothparentsneedtoworktopayfortheirhomeandlivingexpenses.Theyneedtopaysomeonetolookaftertheirchildduringthedaywhichisexpensive. InadditionproblemsintheglobaleconomyoftenaffectBritishfamilies.Forexamplewhentimesaretoughandthereisaneconomicdownturnitbecomesdifficulttofindajoborkeeptheexistingone.Thiskindofuncertaintydiscouragespeoplefromhavinglargerfamilies. SowhatisBritaindoingtotryandsaveBritishfamiliesFirstofallthegovermmentistryingtomakeitcheapertohavechildren.Forexampletherehavebeenincreasesinmoneyfamiliescangainfromthestateeachmonth.Alsothereisanincreasingamountofmoneyfornurseryschoolssothatparentsdon'tneedtopaysomuchforchildcare.Inadditiontherearenowlawsallowingparentstotakemoretimeoffworksothattheycanlookaftertheirchildrenthemselvesratherthanhavingtopayotherstodoit. .
空气中含量较多且性质活泼的气体是
小金用图示装置探究平面镜成像特点．实验探究的步骤如下 A．在水平桌面上铺一张白纸将一块玻璃板竖立在纸上在纸上记下玻璃板的位置． B．选取两支大小相同的蜡烛把一支蜡烛点燃放在玻璃板的前面看到玻璃板后面有蜡烛的像时在纸上记下蜡烛的位置A． C．拿另一支没有点燃的蜡烛竖立着在玻璃板后面移动直到它与前面的蜡烛的像完全重合在纸上记下该蜡烛的位置A′． D．移动点燃的蜡烛到另一位置重做上面的实验在纸上记录物与像的位置BB′CC′． 1刚开始小金在做步骤C时无论怎么移动蜡烛都无法使它与前面的蜡烛的像完全重合．请分析产生这一现象的可能原因．经过改正后小金重新实验． 2步骤D的实验目的是 3图乙是物像的位置实验记录请你利用测量工具对乙图的实验记录作出处理并得到相应规律．
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