课时跟踪检测(二十六) Art
课时跟踪检测(二十六) 正弦定理和余弦定理

课时跟踪检测(二十六) 正弦定理和余弦定理[达标综合练]1.在△ABC 中,若A =60°,C =45°,c =3,则a =( ) A .1 B.322 C.233D .2解析:选B 由正弦定理得,a =c sin A sin C =322.2.△ABC 中,已知面积4S =a 2+b 2-c 2,则角C 的度数为( ) A. 135° B. 45° C. 60°D. 120° 解析:选B 由4S =a 2+b 2-c 2,得4×12ab sin C =2ab cos C ,解得tan C =1,又角C为△ABC 的内角,所以C =45°.3.在△ABC 中,如果A =60°,c =4,23<a <4,则此三角形有( ) A .无解 B .一解 C .两解D .无穷多解解析:选C 根据正弦定理,可得a sin A =csin C ,所以sin C =c ·sin A a =23a , 因为23<a <4,所以sin C ∈⎝⎛⎭⎫32,1, 又由c >a ,则60°<C <120°,有两个C 满足条件,所以此三角形有两解. 4.在△ABC 中, cos 2B 2=a +c2c ,则△ABC 的形状为( )A .正三角形B .直角三角形C .等腰或直角三角形D .等腰直角三角形解析:选B 因为cos 2B 2=1+cos B 2,所以1+cos B 2=a +c 2c ,有cos B =ac =a 2+c 2-b 22ac ,整理得a 2+b 2=c 2,故C =π2, △ABC 的形状为直角三角形.5.已知锐角三角形的三边长分别为1, 2, a ,则a 的取值范围是( ) A .(3,5) B .(3,5) C .(3,5)D .(5,3)解析:选A 要使锐角三角形的三边长分别为1, 2,a ,则保证2所对应的角和a 所对应的角均为锐角即可,即⎩⎪⎨⎪⎧1+a 2-42a>0,1+4-a24>0,a >0,解得3<a < 5.6.在△ABC 中,角A ,B ,C 的对边分别为a ,b ,c ,若a cos B +b cos A =4sin C ,则△ABC 的外接圆面积为( )A .16πB .8πC .4πD .2π解析:选C 设△ABC 的外接圆半径为R ,∵a cos B +b cos A =4sin C ,∴由余弦定理可得a ×a 2+c 2-b 22ac +b ×b 2+c 2-a 22bc =2c 22c =c =4sin C ,∴2R =csin C =4,解得R =2,故△ABC 的外接圆面积为S =πR 2=4π.7.如图,点D 是△ABC 的边BC 上一点,AB =7,AD =2,BD =1,∠ACB =45°,AC =________.解析:∵AB =7,AD =2,BD =1,∠ACB =45°, ∴由余弦定理可得cos ∠ADB =AD 2+BD 2-AB 22AD ·BD =4+1-72×2×1=-12,∵∠ADB ∈(0,π),∴∠ADB =120°, ∴∠ADC =180°-∠ADB =60°,∴由正弦定理可得AC =AD ·sin ∠ADC sin ∠ACB=2×3222= 6.答案: 68.在△ABC 中,给出下列5个命题:①若A <B ,则sin A <sin B ;②若sin A <sin B ,则A <B ;③若A >B ,则1tan 2A >1tan 2B ;④若A <B ,则cos 2A >cos 2B ;⑤若A <B ,则tan A 2<tan B 2.其中正确命题的序号是__________.解析:在△ABC 中,A <B ⇔a <b ⇔sin A <sin B ⇔sin 2A <sin 2B ⇔cos 2A >cos 2B ,故①②④正确;若A =75°,B =30°,则1tan 150°<1tan 60°,∴③错误;∵0<A <B <π,∴0<A 2<B 2<π2,∴tan A 2<tan B2,故⑤正确.答案:①②④⑤9.(2019·浙江高考)在△ABC 中,∠ABC =90°,AB =4,BC =3,点D 在线段AC 上.若∠BDC =45°,则BD =________,cos ∠ABD =________.解析:如图,易知sin C =45,sin A =35,cos A =45.在△BDC 中,由正弦定理可得BD sin C =BC sin ∠BDC ,∴BD =BC ·sin Csin ∠BDC=3×4522=1225. ∴cos ∠ABD =cos(45°-A )=cos 45°cos A +sin 45°sin A =22×45+22×35=7210. 答案:1225 721010.已知△ABC 中,角A ,B ,C 的对边分别为a ,b ,c ,且2cos C (a cos C +c cos A )+b =0.(1)求角C 的大小;(2)若b =2,c =23,求△ABC 的面积. 解:(1)∵2cos C (a cos C +c cos A )+b =0,∴由正弦定理可得2cos C (sin A cos C +sin C cos A )+sin B =0, ∴2cos C sin(A +C )+sin B =0,即2cos C sin B +sin B =0, 又0°<B <180°,∴sin B ≠0,∴cos C =-12,又0°<C <180°,∴C =120°.(2)由余弦定理可得(23)2=a 2+22-2×2a cos 120°=a 2+2a +4,又a >0,∴解得a =2,∴S △ABC =12ab sin C =3,∴△ABC 的面积为 3.11.△ABC 的内角A ,B ,C 的对边分别为a ,b ,c .已知△ABC 的面积为a 23sin A .(1)求sin B sin C ;(2)若6cos B cos C =1,a =3,求△ABC 的周长. 解:(1)由题设得12ac sin B =a 23sin A ,即12c sin B =a 3sin A. 由正弦定理得12sin C sin B =sin A 3sin A ,故sin B sin C =23.(2)由题设及(1)得cos B cos C -sin B sin C =-12,即cos(B +C )=-12.所以B +C =2π3,故A =π3.由题设得12bc sin A =a 23sin A,即bc =8.由余弦定理得b 2+c 2-bc =9,即(b +c )2-3bc =9, 解得b +c =33.故△ABC 的周长为3+33.12.(2019·全国卷Ⅲ)△ABC 的内角A ,B ,C 的对边分别为a ,b ,c .已知a sin A +C2=b sin A .(1)求B ;(2)若△ABC 为锐角三角形,且c =1,求△ABC 面积的取值范围. 解:(1)由题设及正弦定理得sin A sin A +C2=sin B sin A .因为sin A ≠0,所以sin A +C2=sin B .由A +B +C =180°, 可得sin A +C 2=cos B 2,故cos B 2=2sin B 2cos B2.因为cos B 2≠0,所以sin B 2=12,所以B =60°.(2)由题设及(1)知△ABC 的面积S △ABC =34a . 由(1)知A +C =120°,由正弦定理得a =c sin A sin C =sin (120°-C )sin C =32tan C +12.由于△ABC 为锐角三角形, 故0°<A <90°,0°<C <90°.结合A +C =120°,得30°<C <90°, 所以12<a <2,从而38<S △ABC < 32.因此△ABC 面积的取值范围是⎝⎛⎭⎫38,32. [素养强化练]1.[数学运算]已知在△ABC 中,角A ,B ,C 所对的边分别为a ,b ,c ,b cos ∠BCA =a ,点M 在线段AB 上,且∠ACM =∠BCM .若b =6CM =6,则cos ∠BCM =( )A.104B.34C.74D.64解析:选B 设∠ACM =∠BCM =θ,则∠BCA =2θ. 又a =b cos ∠BCA ,b =6CM =6, ∴a =6cos 2θ,CM =1.则由面积关系S △ACM +S △BCM =S △ABC , 得12×6×1×sin θ+12×1×6cos 2θ×sin θ =12×6×6cos 2θ×sin 2θ,∴sin θcos θ(4cos θ-3)(3cos θ+2)=0. ∵0<θ<π2,∴cos θ=34,故选B.2.[数学建模]线段的黄金分割点定义:若点C 在线段AB 上,且满足AC 2=BC ·AB ,则称点C 为线段AB 的黄金分割点.在△ABC 中,AB =AC ,A =36°,若角B 的平分线交边AC 于点D ,则点D 为边AC 的黄金分割点.利用上述结论,可以求出cos 36°=( )A.5-14B.5+14C.5-12 D.5+12解析:选B 设AB =2,AD =x , 又AB =AC ,所以CD =2-x .由黄金分割点的定义可得AD 2=AC ·CD , 即x 2=2·(2-x ),解得AD =5-1. 在△ABD 中,由余弦定理得cos 36°=AD 2+AB 2-BD 22·AD ·AB =(5-1)2+22-(5-1)22×(5-1)×2=5+14.故选B. 3.[数学运算]已知a ,b ,c 分别是△ABC 三个内角A ,B ,C 所对的边,且a cos C +12c=b .(1)求A ;(2)若a =1,求△ABC 的周长l 的取值范围. 解:(1)∵a cos C +12c =b ,由正弦定理得sin A cos C +12sin C =sin B .又∵sin B =sin(A +C )=sin A cos C +cos A sin C , ∴12sin C =cos A sin C , ∵sin C ≠0,∴cos A =12.又∵0<A <π,∴A =π3.(2)由正弦定理得b =a sin B sin A =2sin B 3,c =2sin C3,∴l =a +b +c =1+23(sin B +sin C ) =1+23[sin B +sin(A +B )] =1+2⎝⎛⎭⎫32sin B +12cos B =1+2sin ⎝⎛⎭⎫B +π6.∵A =π3,∴B ∈⎝⎛⎭⎫0,2π3,∴B +π6∈⎝⎛⎭⎫π6,5π6, ∴sin ⎝⎛⎭⎫B +π6∈⎝⎛⎦⎤12,1. 故△ABC 的周长l 的取值范围为(2,3].。
(江苏物理总复习)课时跟踪检测(二十六) 电源 闭合电路的欧姆定律

课时跟踪检测(二十六)电源闭合电路的欧姆定律一、立足主干知识,注重基础性和综合性1.某无线充电器的输出额定电压为5 V,输出额定电流为2 A。
某款手机的电池容量为4 000 mAh,额定工作电压为4 V。
则()A.无线充电器的内阻为2.5 ΩB.无线充电器以额定电流工作时,发热功率为10 W×104 J×104 J解析:选C充电器内阻和充电器发热功率无法用题中信息求出,故A、B错误;电池充满电后电荷量q=4 000 mAh=4×3 600 C×104C,电池可释放的化学能E=qU×104××104×104 J,选项D错误。
2.(2020·盐城三模)电热水器金属内胆出水口加接一段曲长管道,在电热水器漏电且接地线失效时,能形成“防电墙”,保障人的安全。
如图所示,当热水器漏电且接地线失效时,其金属内胆与大地间电压为220 V,由于曲长管道中水具有电阻(简称“隔电电阻”),因而人体两端的电压不高于12 V,下列说法正确的是()A.曲长管道应选用导电性能好的材料制成B.曲长管道应选用不易导电的材料制成C.“隔电电阻”大于“人体电阻”,且两者并联D.热水器漏电且接地线失效时,“防电墙”使人体内无电流通过解析:选B要使人体两端的电压不高于12 V,漏电电流通过曲长管道时损失的电压要足够大,所以曲长管道应选用不易导电的材料制成,选项A错误,B正确;“隔电电阻”大于“人体电阻”,且两者串联,选项C错误;热水器漏电且接地线失效时,“防电墙”可使人体内有很微弱的电流通过,不会造成人体触电,保障人的安全,选项D错误。
3.(2021·武汉模拟)如图所示,电源电动势为4 V,内阻为1 Ω,电阻R1=3 Ω,R2=R3=4 Ω,R4=8 Ω,电容器C=6.0 μF,闭合S电路达稳定状态后,电容器极板所带电荷量为()×10-5 C×10-5 C ×10-5 C ×10-5 C 解析:选A 由电路结构可知,电路中的总电阻为R 总=R 1+r +R 4(R 2+R 3)R 2+R 3+R 4=8 Ω,电路中的总电流为I =E R 总=0.5 A ,电容器两极板间的电势差为U C =U R 1+U R 2=IR 1+I 2R 2=2.5 V ,电容器极板所带电荷量为Q =CU C ×10-5 C ,故A 正确,B 、C 、D 错误。
高考物理复习高三一轮复习:课时跟踪检测26电流 电阻 电功 电功率

高考物理复习课时跟踪检测(二十六) 电流电阻电功电功率高考常考题型:选择题+计算题1.如图1所示,a、b分别表示由相同材料制成的两条长度相同、粗细均匀电阻丝的伏安特性曲线,下列判断中正确的是( )A.a代表的电阻丝较粗B.b代表的电阻丝较粗C.a电阻丝的阻值小于b电阻丝的阻值图1D.图线表示的电阻丝的阻值与电压成正比2.(2012·浙江高考)功率为10 W的发光二极管(LED灯)的亮度与功率为60 W的白炽灯相当。
根据国家节能战略,2016年前普通白炽灯应被淘汰。
假设每户家庭有2只60 W的白炽灯,均用10 W的LED灯替代。
估算出全国一年节省的电能最接近( )A.8×108 kW·h B.8×1010 kW·hC.8×1011 kW·h D.8×1013 kW·h3.(2012·北京东城模拟)如图2甲所示,在材质均匀的圆形薄电阻片上,挖出一个偏心小圆孔。
在彼此垂直的直径AB和CD两端引出四个电极A、B、C、D。
先后分别将A、B或C、D接在电压恒为U的电路上,如图乙和图丙所示。
比较两种接法中电阻片的热功率大小,应有( )图2A.两种接法电阻片热功率一样大B.接在AB两端电阻片热功率大C.接在CD两端电阻片热功率大D.无法比较4.铜的摩尔质量为m,密度为ρ,每摩尔铜原子中有n个自由电子,今有一根横截面积为S的铜导线,当通过的电流为I时,电子平均定向移动的速率为( )A.光速c B.I neSC.ρIneSmD.mIneSρ[5.(2013·大同模拟)一台国产封闭型贮水式电热水器的铭牌上所列的主要技术参数如下表所示。
根据表( )A.6.8 A B.0.15 AC.4.4 A D.0.23 A6. (2012·北京西城期末)如图3所示电路中,电源电动势为E,内阻为r,电动机内阻为R1。
高考英语 Art课时跟踪检测

闪堕市安歇阳光实验学校课时跟踪检测(二十六) ArtⅠ.单项填空1.(2014·枣庄模拟)—Which city do you like best, Paris, London or Rome?—________. There're good points and bad points about all the three cities.A.Not necessarily B.It's hard to sayC.Not really D.No, I don't2.(2013·名校第四次诊断性测试)One reason for her ________ for city life is that she can have easy access to places like shops and restaurants. A.reference B.preferenceC.performance D.consequence3.A great deal of talking that ________ under casual circumstances may seem to be aimless.A.is occurred B.are occurredC.occurs D.occur4.(2014·哈考前模拟)Would you be kind enough to help the boy ________ Chinese is really hard to learn?A.who B.whoseC.for whom D.which5.(2014·四川省绵阳市第二次诊断)—Did the speaker say anything that ________ you especially?—Not really. Actually I slept through his speech.A.adapted to B.took upC.broke down D.appealed to6.(2014·湖北孝感一模)Shelly had prepared carefully for her biology examination so that she could be sure of passing it at her first ________. A.intention B.effortC.attempt D.sight7.(2014·宿州模拟)—Look!What a mistake!Why?—Sorry, I ________ on it.A.don't concentrateB.hadn't concentratedC.haven't been concentratingD.wasn't concentrating8.Many college students will find ________ jobs to gain enough working experience during their holidays.A.temporary B.permanentC.steady D.important9.(2013·江苏三校4月阶段性考试)Out of the train ________, whose determined daughter died of cancer after being accepted by Guizhou University.A.a woman stepped B.stepped a womanC.did a woman step D.a woman did step10.(2014·高三质检)What worries her most is that her son, who is twenty years old, is not interested in anything and doesn't have a(n) ________ aim of life.A.specific B.ridiculousC.negative D.allergic11.(2014·山师大附中模拟)Despite the fact that all three teams ________ different approaches to the problem, they were all immediate successes. A.acquired B.adaptedC.achieved D.adopted12.John is now working as an interpreter because he ________ an unusual ability to learn languages quickly.A.performs B.possessesC.observes D.supports13.“I believe any ________ young man can go far in our firm. Congratulations!” the manager ended.A.aggressive B.effectiveC.attractive D.sensitive14.All her energies are ________ upon children and she seems to have little time for anything else.A.guided B.aimedC.directed D.focused15.(2014·青岛高三质检)________ is known to us all that the world weather is getting warmer and warmer.A.It B.WhatC.As D.WhichⅡ.完形填空(2014·高三第三次模拟测试)Mother used to ask me what the most important part of the body is. Through the years I would __1__ a guess at what I thought was the correct __2__. When I was younger, I thought sound was very important to us human s, __3__ I said, “My ears, Mommy.” She said, “No. Many people are __4__.”Since making my first attempt, I had considered the correct answer carefully. So several __5__ later, I told her, “Mommy, __6__ is very important to everybody, so it must be our __7__.” She looked at me and told me, “You are learning fast, but the answer is not correct because there are many people who are blind.”1.A.make B.replyC.think D.contribute2.A.guess B.answerC.part D.choice3.A.anyhow B.otherwiseC.therefore D.however4.A.deaf B.blindC.dumb D.disabled5.A.days B.minutesC.months D.years6.A.hearing B.touchingC.sight D.taste7.A.eyes B.earsC.hands D.legsOver the years, Mother asked me a couple more times and always her answer was __8__. Then last year, my grandpa died. Everybody was __9__. When it was our turn to say our final __10__ to Grandpa, my Mom asked me, “Have you found the answer to my usual question — what is the most important body part __11__, my son?”I was __12__ when she asked me this now. I always thought this was a game between her and me. She saw the __13__ on my face and told me, “This question is very important. It shows that you have really lived your life. For every body part you gave me __14__, I have told you were wrong and I have given you an example __15__. But today is the day you need to learn this important lesson.” She looked down at me as only a mother can. I saw her eyes well up with tears. She said, “Son, the most important body part is your __16__.” I asked, “Is it because it holds up my head?”She replied, “No, it is because it can hold the head of a friend or a loved one when they cry. Everybody needs a shoulder to __17__ on sometime in life, my son. I only hope that you have enough love and friends that you will always have a shoulder to cry on when you __18__ it.”Then and there I knew the most important body part is not a selfish one — it is sympathetic to the __19__ of others. People will forget what you said. People will forget what you did. But people will __20__ forget how you made them feel.8.A.right B.wrongC.the same D.different9.A.injured B.hurtC.wounded D.damaged10.A.sorry B.helloC.goodbye D.yes11.A.already B.stillC.though D.yet12.A.pleased B.shockedC.disappointed D.satisfied13.A.confusion B.smileC.question D.excitement14.A.in the future B.at presentC.in the past D.for the moment15.A.how B.whyC.what D.where16.A.back B.headC.neck D.shoulder17.A.cry B.restC.put D.carry18.A.accept B.getC.need D.have19.A.embarrassment B.painC.anger D.awareness20.A.never B.everC.completely D.foreverⅢ.阅读理解(2014·沈阳四校高三联考)We're so well educated — but we're useless students who have lost the ability to do anything practical.The only thing we've mastered is consumption.Large numbers of students have entered higher education in the past 10 years, but despite being the most educated generation in history, it seems that we've grown increasingly ignorant when it comes to basic life skills.Looking back on my first couple of weeks of living in student halls, I consider myself lucky to still be alive.Unfamiliar to freshers, there are many hidden dangers in the dirty corners of student accommodation.I have survived a couple of serious boiling egg incidents and lots of cases of foodpoisoning, probably from dirty kitchen counters.Although some of my clothes have fallen victim to ironing experimentation, I think I have now finally acquired all the domestic skills I missed out in my modern education.In 2006 and 2010, the charming educationist Sir Ken Robinson gave two very amusing talks in which he discussed the importance of creativity in education.Robinson's main viewpoint is that our current education system dislocates people from their natural talents.I would like to go a step further and propose that besides our talents, the system takes away what used to be passed from generation to generation — a working knowledge of basic life skills.Today's graduates may have earned themselves honor in history, law or economies, but when it comes to simple things like putting up a shelf to hold all their academic books, or fixing a hole in their ontrend clothes, they have to call for help from a professional handyman or tailor.Since the invention of the Internet, it has never been easier for people to access information, but our highly specialized education has made us more onesided than ever.I suggest that we start with the immediate reintroduction of some of the most vital aspects of “domestic science” education, before the current lack leads to serious accidents in student halls.1.People call us useless students for the reason that ________.A.what we've learned is beyond consumptionB.we are educated generationC.we've entered higher educationD.our living skills are so poor2.According to Robinson's opinion, our current education ________. A.focuses on the importance of creativityB.dislocates people from their natural talentsC.has equipped students with basic life skillsD.has followed the tradition properly3.Why are the graduates poor at basic life skills?A.Because they are not interested in them.B.Because they have little relevant practice.C.Because they are affected by the Internet.D.Because they are easy to be onesided.4.The main purpose of writing the passage is that ________.A.there is no need to introduce “domestic science”B.it's time we did something to current educationC.more attention should be paid to natural scienceD.accidents should be prevented in student halls答案Ⅰ.1.选B A项意为“不必要”;B项意为“很难说”;C项意为“不是真的”;D项意为“不,我不会”。
高三英语一轮复习课时作业26:Unit 1《Art》(新人教版选修6)

Ⅰ.多项选择1.The idea of working abroad really ________ me, and I'm trying to apply for a job abroad.A.adapts to B.relates toC.responds to D.appeals to[解析]句意:去国外工作的想法吸引着我,我正试图在国外找到一份工作。
appeal to 意为“有吸引力”,符合句意。
adapt to 适应(新环境等);relate to sb./sth.理解或同情某人(某事物);respond to 回应,反应。
[答案]D2.John applied for the post of Eliot's secretary.Does he______ the necessary patience and ability to do the job well?A.perform B.possessC.observe D.support[解析]句意:John 申请做Eliot 的秘书。
他有做好这项工作必备的耐性和能力吗?possess 具有,拥有,符合句意。
perform 表演,演奏;observe 观察,观测;support 支持,支撑。
[答案]B3.(2012·蚌埠二中期中考试)Rivera Street is dark ________ the light from 14-year-old Lona Zhao's upstairs bedroom.A.instead of B.in spite ofC.except for D.but for[解析]except for 除了,用来对前面的情况进行校正说明。
[答案]C4.He's one of those early birds.It's ________ of him to get up early.A.practical B.humorousC.rude D.typical[解析]It is typical of sb.to do sth.某人做……是他的特征。
正弦定理和余弦定理26

课时跟踪检测(二十六)正弦定理和余弦定理[高考基础题型得分练]1.在△ABC中,若AB=13,BC=3,∠C=120°,则AC=() A.1 B.2 C.3 D.4答案:A解析:设△ABC中,角A,B,C的对边分别为a,b,c,则a=3,c=13,∠C=120°,由余弦定理,得13=9+b2+3b,解得b=1,即AC=1.2.两座灯塔A和B与海岸观察站C的距离相等,灯塔A在观察站南偏西40°,灯塔B在观察站南偏东60°,则灯塔A在灯塔B的()A.北偏东10°B.北偏西10°C.南偏东80°D.南偏西80°答案:D解析:由条件及题图可知,∠A=∠CBA=40°,又∠BCD=60°,所以∠CBD=30°,所以∠DBA=10°,因此灯塔A在灯塔B南偏西80°.3.[2018·山西临汾五校联考]在△ABC中,角A,B,C所对的边分别为a,b,c,若b cos A+a cos B=c2,a=b=2,则△ABC的周长为()A.5 B.6 C.7 D.7.5答案:A解析:由正弦定理,得 sin B cos A +sin A cos B =c sin C , 即sin(A +B )=sin C =c sin C , 又sin C >0,∴c =1,故周长为a +b +c =2+2+1=5,故选A.4.[2018·东北三省哈尔滨、长春、沈阳、大连四市联考]已知△ABC 中,内角A ,B ,C 的对边分别为a ,b ,c ,a 2=b 2+c 2-bc ,bc =4,则△ABC 的面积为( )A.12 B .1 C.3 D .2 答案:C解析:∵a 2=b 2+c 2-bc ,∴cos A =12,∴A =π3,又bc =4,∴△ABC 的面积为12bc sin A =3,故选C.5.在△ABC 中,已知b =40,c =20,C =60°,则此三角形的解的情况是( )A .有一解B .有两解C .无解D .有解但解的个数不确定 答案:C解析:由正弦定理,得b sin B =csin C ,∴sin B =b sin Cc =40×3220=3>1.∴角B 不存在,即满足条件的三角形不存在.6.[2018·东北三省三校联考]△ABC 的内角A ,B ,C 的对边分别为a ,b ,c ,则“a >b ”是“cos 2A <cos 2B ”的( )A .充分不必要条件B .必要不充分条件C .充要条件D .既不充分也不必要条件 答案:C解析:因为在△ABC 中,a >b ⇔sin A >sin B ⇔sin 2A >sin 2B ⇔2sin 2A >2sin 2B ⇔1-2sin 2A <1-2sin 2B ⇔cos 2A <cos 2B .所以“a >b ”是“cos 2A <cos 2B ”的充分必要条件.7.[2017·安徽淮北二模]在△ABC 中,角A ,B ,C 的对边分别为a ,b ,c ,若a 2=3b 2+3c 2-23bc sin A ,则C =________.答案:π6解析:由余弦定理,得a 2=b 2+c 2-2bc cos A ,所以b 2+c 2-2bc cosA =3b 2+3c 2-23bc sin A ,整理得3sin A -cos A =b 2+c2bc ,即2sin ⎝ ⎛⎭⎪⎫A -π6=b 2+c 2bc ≥2,因此b =c ,A -π6=π2,得A =2π3,所以C =π-2π32=π6.8.[2018·江西南昌二中模拟]在△ABC 中,如果cos(B +A )+2sin A sin B =1,那么△ABC 的形状是________.答案:等腰三角形解析:∵cos(B +A )+2sin A sin B =1, ∴cos A cos B +sin A sin B =1, ∴cos(A -B )=1,在△ABC 中,A -B =0⇒A =B , ∴△ABC 是等腰三角形.9.[2018·陕西八校联考]设△ABC 的三边长分别为a ,b ,c ,面积为S ,且满足S =a 2-(b -c )2,b +c =8,则S 的最大值为________.答案:6417解析:∵S =a 2-(b -c )2,b +c =8, ∴12bc sin A =2bc -(b 2+c 2-a 2) =2bc -2bc cos A , 即sin A +4cos A =4.联立⎩⎨⎧sin A +4cos A =4,sin 2A +cos 2A =1,解得sin A =817,∴S =12bc sin A =417bc ≤417×⎝ ⎛⎭⎪⎪⎫b +c 22=6417, 当且仅当b =c =4时等号成立.10.如图,为测得河岸塔AB 的高,先在河岸上选一点C ,使C 在塔底B 的正东方向上,测得点C 到点A 的仰角为60°,再由点C 沿北偏东15°方向走10米到位置D ,测得∠BDC =45°,则塔AB 的高是________米.答案:106解析:在△BCD 中,CD =10,∠BDC =45°, ∠BCD =15°+90°=105°,∠DBC =30°, 由正弦定理得BC sin 45°=CDsin 30°, 所以BC =CD sin 45°sin 30°=10 2. 在Rt △ABC 中,tan 60°=ABBC , AB =BC tan 60°=106(米).[冲刺名校能力提升练]1.在△ABC 中,内角A ,B ,C 所对的边分别是a ,b ,c ,若c 2 =(a -b )2+6,C =π3,则△ABC 的面积是( )A .3 B.932 C.332 D .3 3 答案:C解析:∵c 2=(a -b )2+6,∴c 2=a 2+b 2-2ab +6.① ∵C =π3,∴c 2=a 2+b 2-2ab cos π3=a 2+b 2-ab .② 由①②,得-ab +6=0,即ab =6. ∴S △ABC =12ab sin C =12×6×32=332.2.[2018·江西南昌一模]在△ABC 中,角A ,B ,C 所对的边分别是a ,b ,c ,若c =1,B =45°,cos A =35,则b =( )A.53B.107C.57D.5214 答案:C解析:因为cos A =35, 所以sin A =1-cos 2A =1-⎝ ⎛⎭⎪⎫352=45, 所以sin C =sin[180°-(A +B )] =sin(A +B )=sin A cos B +cos A sin B =45cos 45°+35sin 45°=7210.由正弦定理b sin B =csin C ,得 b =17210×sin 45°=57. 3.[2017·河北武邑三模]在△ABC 中,B =π4,角A 的平分线AD 交BC 于点D ,设∠BAD =α,sin α=55.(1)求sin C ;(2)若BA →·BC →=28,求AC 的长. 解:(1)因为α∈⎝ ⎛⎭⎪⎫0,π2,sin α=55, 所以cos α=1-sin 2α=255,则sin ∠BAC =sin 2α=2sin αcos α=2×55×255=45, 所以cos ∠BAC =cos 2α=2cos 2α-1=2×45-1=35,sin C =sin ⎣⎢⎡⎦⎥⎤π-⎝ ⎛⎭⎪⎫π4+2α=sin ⎝ ⎛⎭⎪⎫π4+2α=22cos 2α+22sin 2α=22×35+22×45=7210.(2)由正弦定理,得AB sin C =BC sin ∠BAC ,即AB 7210=BC45,所以AB =728BC .因为BA →·BC →=28,所以AB ×BC ×22=28, 由以上两式解得BC =42,由AC sin B =BC sin ∠BAC ,AC 22=BC 45,所以AC =5.4.如图所示,摄影爱好者S 在某公园A 处,发现正前方B 处有一立柱,测得立柱顶端O 的仰角和立柱底部B 的俯角均为π6.设S的眼睛到地面的距离为3米.(1)求摄影爱好者到立柱的水平距离和立柱的高度;(2)立柱的顶端有一长2米的彩杆MN 绕其中点O 在S 与立柱所在的平面内旋转.摄影爱好者有一视角范围为π3的镜头,在彩杆转动的任意时刻,摄影爱好者是否都可以将彩杆全部摄入画面?请说明理由.解:(1)作SC 垂直OB 于C ,则∠CSB =π6,∠ASB =π3.又SA =3,故在Rt △SAB 中,可求得BA =3, 即摄影爱好者到立柱的水平距离为3米. 由SC =3,∠CSO =π6,在Rt △SCO 中,可求得OC = 3. 因为BC =SA =3,故OB =23, 即立柱高为23米.(2)连接SM ,SN ,设SN =a ,SM =b . 由(1)知SO =23, 在△SOM 和△SON 中, cos ∠SOM =-cos ∠SON ,即(23)2+1-b 22×23×1=-(23)2+1-a 22×23×1,可得a 2+b 2=26.在△MSN 中,cos ∠MSN =a 2+b 2-222ab =11ab ≥22a 2+b 2=1113>12,当且仅当a =b 时等号成立.又∠MSN ∈(0,π),则0<∠MSN <π3. 故摄影爱好者S 可以将彩杆全部摄入画面.。
课时跟踪检测(二十六) Art

课时跟踪检测(二十六)ArtⅠ.单项填空1.—Do you think I should join the singing group, Mary?—________ If I were in your shoes, I certainly would.A.None of your business.B.It depends.C.Why not? D.I don't think so.2.Tom wasn't good at physics at first, but his physics has improved ________ since the new teacher began teaching him.A.a great deal B.scores ofC.plenty of D.a great many3.(2013·西安八校三联)—What do you think of she Spring Festival Gala of the Snake Year?—To be frank, it didn't ________ me much.A.appeal to B.belong toC.occur to D.refer to4.(2013·高新一中模拟)It's ________ of him to set his aim high but do little, so he is always leaving things undone.A.controversial B.typicalC.conventional D.evident5.(2013·邯郸市高三质检)What worries her most is that her son, who is twenty years old, is not interested in anything and doesn't have a(n) ________ aim of life.A.specific B.ridiculousC.negative D.allergic6.It is known to all that ________ you exercise regularly, you won't stay healthy.A.because B.unlessC.now that D.in case7.(2013·榆林一中第一次诊断)After decades of effort, the city is still trying to ________ how to ban smoking in public places.A.look through B.get throughC.figure out D.take out8.John is now working as an interpreter because he ________ an unusual ability to learn languages quickly.A.performs B.possessesC.observes D.supports9.(2013·浙大附中高三质检)Despite the short stay in this foreign country, he has soon________ himself to the new environment.A.attended B.adoptedC.adapted D.admitted10.(2013·银川二中高三模拟)The noise outside is nearly driving me mad. I wish they ________ that music down.A.had turned B.have turnedC.will turn D.would turn11.Having practiced for months, Bob Beamon broke the world long jump record at his first ________ in the 1968 Olympic final in Mexico.A.attempt B.desireC.intention D.sight12.(2013·宁波高三质检)—You need to start exercising again, I guess.—Well, I ________ to eat less recently.But as you know, my mother is such a good cook.A.have been attempting B.had attemptedC.was attempting D.have attempted13.All her energies are ________ upon children and she seems to have little time for anything else.A.guided B.aimedC.directed D.focused14.(2013·安康高三质检)________ is known to us all that the world weather is getting warmer and warmer.A.It B.WhatC.As D.Which15.The young teacher wants to help his students as much as he can, but ________,he'd better help them learn on their own.A.for one thing B.as usualC.in other words D.on the other handⅡ.完形填空(2013·西安六所重点中学高三联考)Long long ago, there was a small village. This village had a __1__ tradition. At the beginning of every year, any boy who had reached the age of majority (成年) was given land and money to build a home. The boy had to __2__ his home before winter. If his home failed to endure the cold weather in winter, the villagers could not __3__ him in any way.One __4__,Paul and Marc reached their majority. They __5__ their land and money and decided to search nearby villages for ideas on building their homes. In each village, they found the nicest __6__ and talked to the owners. Each owner gladly offered __7__.After Marc saw several homes, he __8__ the best ideas and went back to his own land. Paul, __9__,continued collecting more ideas. Soon he had so many great ideas that he began to __10__ some of them. But he always believed he could find even better ideas in the next village.Marc began building his home. He had several false starts, __11__ his home gradually rose from his land. By fall, Marc had finished his home. It wasn't perfect, but it was strong and he could __12__ it later.Paul enjoyed all the beautiful homes and __13__ with home owners. The first snow came and Paul, realizing he was running out of time, __14__ back to his land. He built the best home he could in the time he had, but it was __15__. The first winter storm destroyed his home and he froze to __16__. The villagers mourned for him.Marc __17__ the winter. Each year, Marc searched for other good ideas he could use to make his own home look better. He became a leader in the village, __18__a family, and lived a happy, content life.We all build and improve our own mental homes. It's __19__ and fun for us to search for ideas from other mental home owners, but we only improve our own mental home if we actually __20__ the best ideas.,1.A.strange B.hopefulC.literary D.cultural2.A.find B.makeC.complete D.buy3.A.help B.encourageC.scold D.persuade4.A.winter B.summerC.autumn D.spring5.A.exchanged B.receivedC.recognized D.accepted6.A.girls B.jobsC.houses D.presents7.A.rooms B.drinksC.attention D.advice8.A.expected B.gatheredC.created D.understood9.A.similarly B.finallyC.however D.furthermore10.A.forget B.believeC.replace D.doubt11.A.because B.althoughC.but D.so12.A.repair B.rebuildC.sell D.improve13.A.conversations B.achievementsC.struggles D.arguments14.A.drove B.rushedC.flew D.moved15.A.weak B.funnyC.small D.amazing16.A.blindness B.deathC.sadness D.illness17.A.experienced B.lovedC.survived D.spent18.A.brought B.earnedC.contacted D.raised19.A.slow B.easyC.dangerous D.special20.A.realize B.bringC.collect D.applyⅢ.阅读理解(2013·沈阳二中高三模拟)In eighteen seventy-seven, the American government decided to move the Nez Perce Indians from their land. The government had set up a reservation for them in Idaho. Chief Joseph did not want to leave the land. It was holy ground. It contained the bones of his father and mother.But, like his father in earlier times, Chief Joseph knew it would be hopeless to stay and defend the land. There were too few Indians to win a war against the white men.And so in June of eighteen seventy-seven, the Nez Perce left their home in the Wallowa Valley. They left quickly. They were able to take only a small part of what they owned, and just a few cattle and Appaloosa horses.When the Indians reached the Snake River, the water was very deep and ran very fast with melted snow from the mountains. Chief Joseph and his people made boats from sticks and dried animal skins to cross the river. While the Indians were busy, a group of white men came and stole some of the cattle waiting at the edge of the river.The other chiefs demanded that Joseph call a meeting. Two of the chiefs, White Bird and Toohoolhoolzote, spoke for War, but Joseph held different opinion.Some of the young men in White Bird's group were very angry. That night, they rode into thecountryside and killed eleven white persons.During all his years as chief, Joseph had tried to keep the peace. Now he saw there was no hope. Although he and his young men had taken no part in the killings, he knew that the white men would blame all of the Indians. Chief Joseph said, “I would have given my own li fe if I could have undone the killing of the white men.”Many Nez Perce fled. Chief Joseph remained, because his wife was about to have a baby. After she gave birth, he and his family joined the others in White Bird Canyon to the south.Joseph wanted to lead the people to safety in the flat lands of Montana. But the United States army quickly sent horse soldiers to follow them.They were extremely tired when they reached White Bird Canyon. An Indian — carrying a white flag — walked forward to meet them. A soldier shot him.With that shot, war between the Nez Perce and the United States began.1.Why didn't Chief Joseph want to leave the land?A.He thought the reservation in Idaho wasn't satisfying.B.He didn't want to be separated from his parents.C.He had special feeling for the land where he was living.D.He didn't want to live with the white men.2.Which of the following is TRUE?A.Before they left their home, the Nez Perce had only a few cattle and Appaloosa horses.B.Chief Joseph and his people were unwilling to cross the deep river.C.When the Indians reached the Snake River, it was very hard for them to cross it.D.While the Indians were waiting by the river, a group of white men stole some of the cattle.3.From the passage we can infer that ________.A.Chief Joseph knew it would be hopeless to defend the landB.white men often killed some IndiansC.Chief Joseph was afraid of white menD.conflicts often happened between the Indians and the white4.What might be the title of the passage?A.The story of Chief JosephB.The American Civil WarC.Chief Joseph and his childrenD.The Nez Perce Indians答案课时跟踪检测(二十六)Ⅰ.1.选C句意:“玛丽,你认为我应该去参加合唱团吗?”“为什么不呢,如果我是你的话,我肯定会参加的。
2020版高考英语一轮复习课时提能练26Art含解析新人教版

课时提能练(二十六)Ⅰ.阅读理解A(2019·日照检测)Along with the standard pigments(颜料) and paintbrushes,artist Sean Yoro(known as Hula),requires an unconventional piece of equipment for his particular brand of mural(壁画) making:a paddleboard.The Hawaiian muralist,balanced on the top of the floating platform,describes women from various sites across the world,whose homelands are often threatened by the effects of global warming.For his most recent project,titled“What If You Fly”,Hula traveled to Baffin Island,off the coast of Nunavut,Canada,to paint a portrait of local Inuit woman Jesse Mike,who lives there with her daughter.In a short film telling of the artist's process,Mike explains her frustrating previous experiences working with filmmakers who reported on the terrible circumstances troubling her endangered landscape.“For most people,it's about the polar bears,it's not about the people,”she said.“Well,let's make it about the people.”Hula and his team spent 14 hours searching for the perfect iceberg canvas(油画布),knowing all the while that the ice itself,and any image created on the top of it,would soon melt away into nothing.“It's a little ambitious t o do this largerthanlife ice mural in the Arctic,and somehow,at the same time,make a connection to the human culture,”climber and filmmaker Renan Ozturk said of the project.When Hula found his proper ice,he painted a portrait of Jesse he took earlier on his camera.Working against the power of time and Mother Nature,the artist aimed to finish as much of Jesse's portrait as he could before the iceberg disappeared.The massive image,Hula's most remote and technically challenging piece yet,communicates a memorable reality—the consequences of climate change,first and foremost,affect people.【语篇解读】本文主要叙述了壁画大师Hula去往Baffin Island,通过在冰上画一位因纽特女性的肖像来提醒人们气候变化的后果正在影响人类这一现实。
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课时跟踪检测(二十六)ArtⅠ.单项填空1.(2015·盐城市高三第三次模拟考试)—Well, Jane, what did you want to say when you came in?—Nothing, just________.A.take it easy B.in caseC.forget it D.out of question2.(2015·金丽衢十二校高三第一次联考)Many houses in Ningbo were destroyed by Typhoon Fitow.________,the victims had to live in the temporary shelters.A.To be exact B.As a consequenceC.On the other hand D.In the meantime3.(2015·淮北二模)“I believe any ________ young man can go far in our firm. Congratulations!” the manager ended.A.aggressive B.effectiveC.attractive D.sensitive4.(2015·杭州高级中学高三第六次月考)The palace is heavily guarded, because inside its walls________.A.where sit the European leadersB.the European leaders there sitC.sit the European leadersD.that the European leaders sit5.(2015·金丽衢十二校高三第一次联考)He gave so________a description of the problem that his colleagues thought he was professional.A.central B.casualC.special D.specific6.(2014·嘉兴市高三第一学期期末测试)Father gave me 600 yuan last weekend.Then I spent 500 yuan on clothes and dinner, but I can’t________where another 100 yuan has gone.A.pick out B.figure outC.give out D.leave out7.(2015·扬州市高三第四次调研考试)Heavy smog has returned to the skies of Beijing after a two-month break, with authorities________the pollution will remain due to unfavorable conditions.A.predicting B.predictedC.being predicted D.to predict8.All her energies are ________ upon children and she seems to have little time for anythingelse.A.guided B.aimedC.directed D.focused9.(2014·枣庄模拟)A great deal of talking that ________ under casual circumstances may seem to be aimless.A.is occurred B.are occurredC.occurs D.occur10.(2015·浙大附中考前模拟)Would you be kind enough to help the boy ________ Chinese is really hard to learn?A.who B.whoseC.for whom D.which11.(2015·四川省绵阳市第二次诊断)—Did the speaker say anything that ________ you especially?—Not really. Actually I slept through his speech.A.adapted to B.took upC.broke down D.appealed to12.(2015·湖北孝感一模)Shelly had prepared carefully for her biology examination so that she could be sure of passing it at her first ________.A.intention B.effortC.attempt D.sight13.(2015·丽水一模)—Look!What a mistake!Why?—Sorry, I ________ on it.A.don’t concentrate B.hadn’t concentratedC.haven’t been concentrating D.wasn’t concentrating14.(2015·杭州第二次质量检测)Despite the fact that all three teams ________ different approaches to the problem, they were all immediate successes.A.acquired B.adaptedC.achieved D.adopted15.John is now working as an interpreter because he ________ an unusual ability to learn languages quickly.A.performs B.possessesC.observes D.supportsⅡ.完形填空(2015·宁波十校联考)Optimism and pessimism are both powerful forces.Each of us must choose which we want to __1__our future and our expectations.We can choose to laugh or cry,bless or __2__.It’s our decision: From which perspective do we want to view life?Will we look up in __3__or down in desperation?I believe in the upward look.I choose to __4__the positive and skip right over the negative.An optimistic attitude is not a luxury; it’s a(n)__5__.The way you look at life will determine how you feel, how you perform, and how well you will get along with other people.__6__,negative thoughts,attitudes,and expectations __7__themselves; they become a self-fulfilling prophecy (预言).Pessimism creates a dark place where no one wants to live.Years ago, I drove into a service station to get some gas.It was a beautiful day, and I was feeling great.As I walked into the station to pay for the gas, the attendant said to me,“How do you feel?” That seemed like a(n)__8__question, but I felt fine and told him so.“You don’t look well,” he replied.This __9__me completely by surprise.A little __10__confidently, I told him that I had __11__felt better.Without hesitation, he continued to tell me how bad I looked and that my skin appeared yellow.By the time I left the service station, I was feeling a little __12__.About a block away, I __13__over to the side of the road to look at my face in the mirror.How did I feel?Was I affected with jaundice (黄疸)?Was everything all right?By the time I got home, I was beginning to feel a little nauseous (恶心).Did I have a bad liver?Had I __14__some rare disease?On another beautiful day, when I went into that gas station, feeling __15__again, I figured out what had happened.The place had recently been painted a bright, distasteful __16__,and the light reflecting __17__the walls made everyone inside look as though they had hepatitis (肝炎)!I wondered how many other folks had __18__the way I did.I had let one short conversation with a total __19__change my attitude for an entire day.He told me I looked sick, and before long, I was actually feeling sick.That single __20__observation had a great effect on the way I felt and acted.The only thing more powerful than negativism is a word of optimism and hope.When a whole culture adopts an upward look, incredible things can be accomplished.,1.A.shape B.decideC.preview D.transform2.A.forgive B.curseC.praise D.regret3.A.vain B.angerC.action D.hope4.A.highlight B.analyzeC.evaluate D.introduce5.A.necessity B.opportunityC.quality D.identity6.A.Actually B.ConsequentlyC.Accordingly D.Contrarily7.A.rely on B.feed onC.go on D.take on8.A.familiar B.ordinaryC.odd D.easy9.A.got B.tookC.stopped D.made10.A.more B.lessC.quite D.too11.A.never B.everC.once D.always12.A.uneasy B.unconcernedC.unsatisfied D.unaffected13.A.got B.cameC.took D.pulled14.e up B.brought upC.picked up D.put up15.A.fine B.upsetC.sick D.calm16.A.gray B.blueC.yellow D.red17.A.in B.overC.off D.through18.A.quit B.adaptedC.answered D.reacted19.A.liar B.onlookerC.attendant D.stranger20.A.positive B.negativeC.careful D.rigidⅢ.阅读理解(2015·金华十校高考模拟考试)For years I fought with the bird’s nest that sat on top of my head — my Medusa (神话中的蛇发女妖) hair. No matter what I did and how hard I tried, in no way could I make my unruly (乱蓬蓬) hair to my satisfaction.Growing up in a Russian-Jewish home with parents who thought North American styling products were something illegal such as drugs, I was never allowed to put them in my hair. “Why buy hair gel? Your hair is so beautiful naturally,” my mother would say. The teens at school did not agree. From boys not wanting to kiss me when we played spin the bottle in Grade 7 to being called “the mop”,I suffered from my hair.When I got to university, I believed my hair was a wall that stood between me and everything — finding a part-time job, getting a boyfriend, etc.If only I could find a way to manage the curls and put it behind bars, I told myself, I would feel secure and sexy. I tried everything: rollers, hairspray, gels and, at one point, an iron. Then, in my second year, a miracle happened. I was asked to be a hair model for Japanese hair straightening, a process by which the molecules (分子) of my curls would be broken and reset in a bone-straight position. I was the perfect candidate, the hairdresser told me. Although they said how hair relaxing could damage the scalp (头皮), for the next five years I didn’t find them to be true. All of the hairdresser’s promises were fulfilled: With my hair straight and smooth, I was no longer the “mop”.However, there was extreme damage done to my wallet. To keep up the straightening cost$700 every six months, and that was considered cheap. While some people thought I was crazy, I was willing to do anything to never again feel like that anxious, curly-headed girl in Grade 7. But when I moved out of my parents’house at age 26 and rented an apartment, the upkeep of my new image became too costly.I couldn’t hide from my inner Medusa any longer. It was time to hug her and let her fly. Seeking a choice, I turned to the Internet, Google. After hours of searching, I hit upon a “curly haired”salon, a place designed for girls like me. I doubted these so-called “Curl Ambassadors”could do anything without using machine of some sort, and though I bought the service called the “Curly-Doo”,I suspected I’d have the same unruly mop at the end of the appointment.I dragged my feet so hard getting there that I arrived 45 minutes late. I secretly hoped they would turn me away. Instead, my stylist simply said:“You are very late. Let me see your hair.” At that moment, my world and beliefs about myself were turned upside down along with my hair. As my head was in a basin full of freezing-cold water, then covered with a jelly-like jam, I wondered what I had got myself into.“Do you really think this will work?”I asked the stylist, Jones.“My curls are a disaster.”“No curly hair is hopeless,”she replied.“They just haven’t found a way to work with it, that’s all.”After the hour was over, Jones had completed her work. She had styled my hair using only her hands, water and a mixture of organic jam. I couldn’t believe what I was seeing in the mirror: a naturally curly, Medusa-free me. You could argue that hair is just hair. Yet, it is just such physicalfeatures that have such a large influence on how we view ourselves.According to Jones, 75 percent of the population have a wave or curl in their hair and don’t know what to do with it. Men cut theirs short. Women flat-iron theirs to death. When I read through a beauty magazine or take the subway to work, it makes me sad to see so many people repressing their natural beauty.Since then, my world has changed. I have always been outgoing, but these days I seem to be more outspoken and confident than ever. On top of that, friends and co-workers tell me I am looking better than ever, but they don’t know the source of the change.I don’t need to tell them. My Medusa hair speaks for herself.1. What can we learn about the writer’s hair in the first place?A.Her parents considered it was bird’s nest.B.Teens at school laughed at it as Medusa hair.C.She hated it because it couldn’t be straightened.D.North American styling products harmed her hair.2. Japanese hair straightening caused a problem for the writer that________.A.her wish to feel secure and sexy didn’t come trueB.her hair was seriously damaged after the straighteningC.the cost to keep her hair straight was too high for herD.she was called “the mop” with her hair straight and smooth3.The writer was________when she went to the“curly haired” salon.A.hesitated B.excitedC.disappointed D.determined4.What was the reaction of the stylist in the salon when she saw the writer?A.She was very angry because the writer was late.B.She thought totally the writer’s hair was a disaster.C.She was calm and sure of her work.D.She thought there was no way to fix the writer’s hair.5.The writer’s world has changed because she________.A.has removed her inner MedusaB.has removed her curls on her headC.has found a way to straighten her hair in the stylish salonD.has found the admiration for her from her friends and co-workers6. The best title of the passage can be________.A.A Successful Stylist B.My Medusa HairC.Road to Beauty D.Accept the Way We Are答案Ⅰ.1.选C考查交际用语。