3.1酚课下30分钟演练(人教选修5)一、选择题(本题包括7小题，每小题3分，共21分)1．往下列溶液中加入FeCl3溶液，无明显现象的是()解析：B、C项中分别为邻甲基苯酚和苯酚，均与FeCl3溶液发生显色反应。D项中HI被FeCl3溶液氧化成I2，I2溶于水，呈褐色。答案：A2．下列说法正确的是()A．苯与苯酚都能与溴水发生取代反应B．苯酚与苯甲醇()分子组成相差一个CH2原子团，因而它们互为同系物C．在苯酚溶液中，滴入几滴FeCl3溶液，溶液立...
(时间60分钟，满分80分)一、选择题(共6个小题，每小题5分，满分30分)1．已知函数f(x)＝()x，a，b∈R＋，A＝f()，B＝f()，C＝f()，则A、B、C的大小关系为()A．A≤B≤CB．A≤C≤BC．B≤C≤AD．C≤B≤A解析：≥≥，又f(x)＝()x在R上是单调减函数，∴f()≤f()≤f()．答案：A2．用反证法证明：若整系数一元二次方程ax2＋bx＋c＝0(a≠0)有有理数根，那么a、b、c中至少有一个偶数．用反证法证明时，下列假设正确的是()A．假设a、b、c都...
Unit2课下能力提升(八)Ⅰ.阅读理解Todayjustastechnologychangedthefaceofindustry,farmshaveundergonean“agriculturalrevolution”.Onthefarmoftoday,machinesprovidealmostallthepower.Oneofthemostimportantbenefitswillbethefarmcomputer.Afewforward-lookingfarmersarealreadyusingcomputerstohelpthemruntheirfarmsmoreefficiently.Thecomputershelpthemkeepmorecorrectrecordssotheycanmakebetterdecisionsonwhatcropst...
Unit2课下能力提升(五)阅读理解ALONDON(Reuters)—Organic(有机的)fruit,deliveredrighttothedoorstep.ThatiswhatGabrielGoldprefers,andheiswillingtopayforit.Ifthisisnotpossible,the26yearoldcomputertechnicianwillspendtheextramoneyatthesupermarketbuyingorganicfood.“Organicproduceisalwaysbetter，”Goldsaid.“Thefoodisfreeofpesticides(农药),andyouaregenerallysupportingfamilyfarmsinsteadoflargefarms.Andmo...
Unit5课下能力提升(十八)Ⅰ.根据提示写出单词的正确形式1．Hisheroic________(行为)werecelebratedineverycornerofIndia.2．Youwontwanttomissamomentofthe________(虚幻)magicanddrama.3．We________(想知道)ifCarlwouldbejoiningus.4．He________(摇动)theswordtwicearoundhishead.5．Eyesightshouldbecarefully________(保护).6．Thestudentscomplainedthe________(long)oftheexampaper.7．Climbingandfishingareamongmy____...
Unit1课下能力提升(四)Ⅰ.阅读理解Thepenismorepowerfulthanthesword.Therehavebeenmanywriterswhousetheirpenstowritethingsthatwerewrong.MrsHarrietBeecherStowewasoneofthem.ShewasbornintheU．S.A.in1811.Oneofherbooksnotonlymadeherfamousbuthasbeendescribedasonethatexcitedtheworld,andwashelpfulincausingacivilwarandfreeingtheenslavedrace.ThecivilwarwastheAmericanCivilWarof1861,inwhichtheNorthernStatesfoug...
Unit1课下能力提升(三)Ⅰ.根据提示写出单词的正确形式1．The________(听众)wasnolessthanfivethousand.2．I________(计划；打算)toorganizesomeactivitiesatschoollikelectures,Englishpartiesandsoon.3．Thereisa________(一代)gapbetweenmyparentsandme.4．NowImgoingto________(发表)aspeechontheimportanceofinterpersonalrelationshipstoSeniorHighstudents.5．Mostpeoplewalkatanaverage________(速度)of5kilometersanhou...
