课时作业2
2020-2021学年语文人教版必修2课时作业：第2课 故都的秋
课时作业2故都的秋第一课时基础巩固一、积累运用1．下列加点字的读音完全正确的一项是(C)A．一椽．(yuán)廿．四(niàn)扫．帚(sào)B．潭柘．寺(zhé)房檩．(lǐn)普陀．山(tuó)C．平仄．(zè)譬．如(pì)厦．门(Xià)D．椭．圆(tuǒ)落蕊．(ruǐ)橄．榄(gān)解析：A项，“椽”应读“chuán”；B项，“柘”应读“zhè”；D项，“橄”应读“gǎn”。
2．下列句子中加点的成语使用错误的一项是(C)A．我的不远千里．．．．，要从杭州赶上青岛，更要从青岛赶上北平来的理由，也不过想饱尝一尝这“秋”，这故都的秋味。
B．在华语乐坛上占有特殊一席的女歌手齐豫即将在北京举办演唱会，然而在发布会上，齐豫却不能自已．．．．地泣不成声，因为她宣称这将是自己最后一次举办演唱会。
C．显然，打造“信用政府”和发展“民营经济”这两个热点，在民众的关怀下不期而遇．．．．。
D．一个明智的人应当具有一叶知秋．．．．、举一反三的能力。
解析：A项，不远千里：不以千里为远。
形容不怕路途遥远。
使用正确。
B项，不能自已：无法控制自己，使激动的情绪平静下来。
使用正确。
C项，不期而遇：没有约定而意外地相遇，适用于人。
此处用错对象，此处是指“信用政府”和“民营经济”惠及民众。
D项，一叶知秋：从一片树叶的凋落，知道秋天的到来。
比喻通过个别的细微的迹象，可以看到整个形势的发展趋向与结果。
使用正确。
3．下列句子中加点虚词使用不正确的一项是(B)A．我虽．则外国诗文念得不多，也不想开出账来，做一篇秋的诗歌散文钞。
B．若．你去一翻英德法意等诗人的集子，或各国的诗文的Anthology来，总能够看到许多关于秋的歌颂与悲啼。
C．南国之秋，当然是也有它的特异的地方的，譬如．．廿四桥的明月，钱塘江的秋潮，普陀山的凉雾，荔枝湾的残荷等等，可是色彩不浓，回味不永。
人教版七年级数学上册教师用书配套课件 课时作业 (2)
自主解答：B
名师点津：有关线段的计算注意问题 1．线段的长度和有理数一样，可以进行加减等运算． 2．如果题目中没有图形，一定要先画出图形，数形结合思想 是数学学习的一种重要方法，应特别注意对线段的中点的灵活运 用．
知识点 3 线段性质的应用 【例 3】平面上有 A，B，C，D 四个村庄，为解决当地缺水 问题，政府准备投资修建一个蓄水池，不考虑其他因素，请你画 图确定蓄水池 H 的位置，使它与四个村庄的距离之和最小(A，B， C，D 四个村庄的地理位置如图所示)，你能说明理由吗？
自主解答：解：(1)3； (2)当 PA＝PB 时，点 P 的位置有两种情况： ①P 为 AB 的中点，此时 PA＋PB＝AB；②P 不在 AB 上，此 时 PA＋PB＞AB. 规律总结：比较线段长短的方法 1．度量法：用刻度尺量出两条线段的长度，再比较长短． 2．叠合法：利用直尺和圆规把线段放在同一条直线上，使其 中一个端点重合，另一个端点位于重合端点同侧，根据另一端点 与重合端点的远近来比较长短．
知识点 1 线段的比较与画法 【例 1】已知线段 AB＝8，平面上有一点 P. (1)若 AP＝5，PB 等于多少时，点 P 在 AB 上？ (2)当 PA＝PB 时，确定点 P 的位置；并比较 PA＋PB 与 AB 的大小．
思路点拨：(1)只有 AP＋PB＝8 时，点 P 在 AB 上； (2)要分类讨论，点 P 的位置有两种情况．
A．3 cm C．11 cm
B．6 cm D．14 cm
解析：∵D 是 AC 的中点，∴AC＝2DC，∵CB＝4 cm，DB ＝7 cm，∴CD＝BD－CB＝3 cm，∴AC＝6 cm，故选 B.
2．已知线段 AB＝8，延长 AB 到点 C，使 BC＝12AB，若 D 为 AC 的中点，则 BD 等于( B )
2023版新教材高中英语Unit2TravellingAround课时作业二Di新人教版必修第一册
课时作业(二) Discovering Useful Structures &Listening and T alking必备知识基础练进阶训练第一层Ⅰ.单词拼写1．The ________ (景色) from the top of the tower was wonderful.2．The little boy opened two ________ (包裹) of cookies.3．The newly built school library will be a useful________(来源)of information for us.4．Please supply the following ________ (细节): name, age and sex while filling in the form.5．China's efforts in the ________ (经济的) growth and poverty alleviation (扶贫) fight set a good example for other countries in the world.6．The peak (高峰) of train ________ (交通运输系统) is expected to appear on Wednesday, Oct.1—the first day of the National Day holiday.Ⅱ.单句语法填空1．It is reported that a 3% ________ (economy) growth is the government's aim.2．Provide the doctor with your ________ (detail) medical history so that you can get a better treatment.3．It was ________ (believable) that the fans waited outside the gym for three hours to have a look at Y ao Ming.4．Jane saw her sister off at the railway station, waving until the train was out ________ sight.5．Lucy made a speech in the English class, and the teacher asked us tomake some comments ________ her performance.6．They had an accident on the road, so they didn't check ________ at their hotel until midnight.7．In Britain, women today make ________ 44% of the workers and nearly half the mothers with children are in paid work.8．In middle schools of that country, boys are requested not ________ (wear) long hair.9．My parents ________ (take) me to Beijing to visit T singhua University next weekend.10．Varieties of waste flew into the water in the past, ________ (kill) river and sea life.Ⅲ.单元语法练习1．When our guest ________ (arrive), I will pick him up at the airport.2．Sophia ________ (go) to the airport because she has to pick up her grandma tonight.3．Ladies and gentlemen, please turn off your cellphones or laptops. The plane ________ (take) off.4．If you ________ (come) to my hometown next month, I'll treat you to a big dinner.5．We ________ (fly) to Shanghai tomorrow so we'd better get our package packed now.6．Please call the station to make sure when the earliest train ________ (leave).7．Close the door of fear behind you, and you ________ (see) the door of faith open before you.8．Mary ________ (leave) for Shenyang by plane at 3：00 this afternoon.Ⅳ.完成句子1．他两小时后将赴伦敦和经理会面。
课时作业2：Unit 4 第二课时
Why don’t you talk to your parents?Section A (3a-4c)一．用词的适当形式填空：1. Last year he usually felt bored with his study and his grades ____________(drop).2. Do you mind __________(open) the window?3. I want to do it in a p_________way. But I don’t know how to do it.4. Alice ________ (厌恶)to do the dishes, but she likes sweeping the floor.5. Playing computer games too much is a ________(浪费) of your time.6. My bike is broken. Could you ________ (借给)me yours, please?7. His parents are very busy. They have little time to c ________with their children.8. He is ready to help others, and he always o money to the people in the poor villages.9. If you borrow books from the library, you should r ___them on time.10. I feel really n _____(紧张的)before the final examination.11. P ______(也许)he will come for afternoon tea,but I’m not sure.12.When I came in, I found him _________(write) something on his seat..13.A Malaysia airplane was missing on March 8th, can you i what happened to thisplane? Was it exploded （爆炸）or being hijacked (劫持了)?14. We should tell them ____________(not wear) the unusual clothes.15. We must study hard and be a ______________(success)person.16. There parents aren’t here,so they look after ________________(they).17. This is a _______________(type) farmer family.18. China is improving(改善)___________(关系)with other countries.19. I don’t know when he will come tomorrow. I will call you as soon as he _______(arrive)20. W_________I said, he didn’t agree with me.二．单项选择：1. I had a hard time with math and I wasn’t ______ to get the bad report from my math teacher.A. sureB. surprisedC. excitedD. interested2. I’m going to take a vacation. Could you please _____me _____some information aboutinteresting places to travel?A. offer, toB. offer, forC. provide, withD. provide, for3. Few people think about what they can do _______others.A. helpB. to helpC. helpingD. helped4---Do you mind _________your room?---No, I’l l do that after finishing _________this article.A. clean, writeB. clean, writingC. cleaning, writeD. cleaning, writing5. Mr. Black asks the kids ________ in the river, because it’s too dangerous.A. swimB. to swimC. not to swimD. swims6. Mr.Li asks us to remember that ____careful we are,_____mistakes we will make.A. the more,the lessB.the more, the moreC. the more, the fewerD. the less, the fewer7. Mary’s grandpa is always ______ in the mountain village.He tells her he feels very______. So she’s going to visit him next week.A. alone; aloneB. lonely; lonelyC. lonely; aloneD. alone; lonely8. Thank you for your help, Linda. You made ________ possible for us to finish the work in time.A. thisB. itC. themD. that9. My sister ______ go to bed _______ my mother came back last night.A. not untilB. doesn't; untilC. didn't; untilD. aren't; until10. Can you _______ me your bike?---With pl easure. But you mustn’t ____ it to others.A. lend, borrowB. borrow, lendC. lend, lendD. borrow, borrow11. ---I am not going swimming tomorrow afternoon.----_____. I have to clean up my bedroom.A. So am IB. Neither am IC. neither I amD. so I am12. Could you please_____ the piano so loudly? Your brother is having a rest now.A. not to playB. not playC. don’t playD. to not play13. This math question is too difficult. Can you help me ?A.work on itB.work out itC.work it outD.work for it14.—What’s wrong?—I can’t do my homework now. I my homework in the classroom this morning.A.leaveB.forgetC.forgotD.left15. He is very angry with his mother, because his mother always him with the best student.paresplainsC.tellsD.makes16. He should the teacher.A.explainB.explain toC.explainedD.explained to17. —— Hurry up. The bus is coming!——Oh, no, we mustn’t cross the street ______ the traffic lights are green.A. afterB. sinceC. whenD. before18. ---Could I watch TV? ---No, you ___. You ____finish your homework first.A. can’t, mustB. can’t, canC. couldn’t, mustD. couldn’t, can19. ---Could I _____your bicycle? ---Sure, and you can ______for a week.A. borrow, borrowB. borrow, keepC. lend, lendD. lend, borrow20. Mary will make a plan as soon as she ____________her homework.A. finishesB. finishC. will finishD. finished参考答案一. 1dropped, 2 open 3. proper 4. hates 5waste 6. lend 7. communicate8. offers 9. return 10. nervous 11. perhaps 12. writing 13. imagine 14. not to wear 15. successful 16. themselves 17. typical 18. relations 19. arrives 20. whatever二．单项选择：1---5. BCBDC 6---10. CDBCC 11---15. BBCDA 16---20. BDABA。
人教版高中数学高二选修2-2课时作业1-2导数的计算
课时作业2 导数的计算一、选择题1．若对任意x 属于R ，f ′(x )＝4x 3，f (1)＝－1，则f (x )是( )A ．f (x )＝x 4B ．f (x )＝x 4－2C ．f (x )＝4x 3－5D ．f (x )＝x 4＋2设f (x )＝x 4＋b ，∵f (1)＝－1，∴b ＝－2，∴f (x )＝x 4－2.故应选B.B2．函数y ＝12(e x ＋e －x )的导数是( ) A.12(e x －e －x ) B.12(e x ＋e －x ) C ．e x －e －x D ．e x ＋e －xy ′＝⎣⎢⎡⎦⎥⎤12(e x ＋e －x )′＝12(e x －e －x )． 故应选A.A3．若函数y ＝x 2＋a 2x (a ＞0)的导数为0，则实数x 是( )A ．aB ．±aC ．－aD ．a 2y ′＝⎝ ⎛⎭⎪⎪⎫x 2＋a 2x ′＝2x ·x －(x 2＋a 2)x 2＝x 2－a 2x 2，由x 2－a 2＝0得x ＝±a .故应选B.B4．函数f (x )＝2a 3＋5a 2x 2－x 6的导数为( )A ．6a 2＋10ax 2－x 6B ．2a 3＋10a 2x －6x 5C ．10a 2x －6x 5D ．5a 2x －6x 5f ′(x )＝(2a 3＋5a 2x 2－x 6)′＝10a 2x －6x 5.故应选C.C5．下列函数在x ＝0处没有切线的是( )A ．y ＝3x 2＋cos xB ．y ＝x sin xC ．y ＝1x ＋2xD ．y ＝1cos x∵y ′＝⎝ ⎛⎭⎪⎫1x ＋2x ′＝⎝ ⎛⎭⎪⎫1x ′＋(2x )′＝－1x 2＋2， ∴当x ＝0时，函数无定义，且y ′不存在，故该函数在x ＝0处没有切线．故应选C.C6．若曲线y ＝x n 在x ＝2处的导数为12，则n ＝( )A ．1B ．2C ．3D ．4y ′＝(x n )′＝n ·x n －1.由n ·2n －1＝12得n ＝3.故应选C.C7．已知函数f (x )在x ＝1处的导数为3，则f (x )的解析式可能为( )A ．f (x )＝(x －1)3＋3(x －1)B ．f (x )＝2(x －1)C ．f (x )＝2(x －1)2D ．f (x )＝x －1f (x )＝(x －1)3＋3(x －1)，∵f ′(x )＝3(x －1)2＋3，∴f ′(1)＝3.故应选A.A8．设函数y ＝f (x )是线性函数，已知f (0)＝1，f (1)＝－3，则f ′(x )＝( )A ．4xB ．－4C ．－2D ．6由f (x )是线性函数，可设f (x )＝ax ＋b (a ，b 为常数，且a ≠0)，由f (0)＝1，f (1)＝－3，解得a ＝－4，b ＝1，∴f (x )＝－4x ＋1，∴f ′(x )＝－4.故应选B.B二、填空题9．曲线y ＝4x 3在点Q (16,8)处的切线的斜率是________．∵y ＝x 34 ，∴y ′＝34x 34 -1 ＝34x -14 ， ∴y ′| x =16＝38.3810．曲线y ＝x 3＋x ＋1在点(1,3)处的切线方程是________．令f (x )＝x 3＋x ＋1，由导数的几何意义知在点(1,3)处的切线斜率k ＝f ′(1)＝3×12＋1＝4.所以由点斜式得切线方程为y －3＝4(x －1)，即4x －y －1＝0.4x －y －1＝1011．曲线y ＝x 3在点(1,1)处的切线与x 轴、直线x ＝2所围成的三角形的面积为________．y ′＝3x 2，所以k ＝y ′⎪⎪x ＝1＝3，所以切线方程为y －1＝3(x －1)，即y ＝3x －2.由⎩⎨⎧ y ＝3x －2x ＝2，解得⎩⎨⎧ x ＝2y ＝4，所以S ＝12×43×4＝83. 83 12．曲线y ＝x 3在点(a ，a 3)(a ≠0)处的切线与x 轴、直线x ＝a 所围成的三角形的面积为16，则a ＝________. y ′＝3x 2，所以切线方程为y －a 3＝3a 2(x －a )，即y ＝3a 2x －2a 3.可求得切线与x 轴的交点为⎝ ⎛⎭⎪⎫23a ，0，与直线x ＝a 的交点为(a ，a 3)，所以三角形面积为S ＝12×a 3×a 3＝16，解得a ＝±1. ±1三、解答题13．已知抛物线y ＝ax 2＋bx ＋c 通过点P (1,1)，且在点Q (2，－1)处与直线y ＝x －3相切，求实数a ，b ，c 的值．∵曲线y ＝ax 2＋bx ＋c 过点P (1,1)，∴a ＋b ＋c ＝1. ① ∵y ′＝2ax ＋b ，∴y ′|x =2＝4a ＋b ，∴4a ＋b ＝1. ②又曲线过点Q (2，－1)，∴4a ＋2b ＋c ＝－1. ③ 联立①②③解得a ＝3，b ＝－11，c ＝9.14．(1)求曲线y ＝2x x 2＋1在点(1,1)处的切线方程； (2)运动曲线方程为S ＝t －1t 2＋2t 2，求t ＝3时的速度． (1)∵y ′＝2(x 2＋1)－2x ·2x (x 2＋1)2 ＝2－2x 2(x 2＋1)2，y ′| x =1＝2－24＝0， 即曲线在点(1,1)处的切线斜率k ＝0，因此曲线y ＝2x x 2＋1在(1,1)处的切线方程为y ＝1.(2)S ′＝⎝ ⎛⎭⎪⎪⎫t －1t 2′＋(2t 2)′ ＝t 2－2t (t －1)t 4＋4t＝－1t 2＋2t 3＋4t . S ′| t =3＝－19＋227＋12＝112627. 15．已知函数f (x )＝ax 4＋bx 3＋cx 2＋dx ＋e 为偶函数，它的图象过点A (0，－1)，且在x ＝1处的切线方程为2x ＋y －2＝0，求函数y ＝f (x )的表达式．∵f (x )是偶函数，f (－x )＝f (x )，∴b ＝d ＝0，f (x )＝ax 4＋cx 2＋e ，又∵图象过点A (0，－1)，∴e ＝－1，∴f (x )＝ax 4＋cx 2－1，f ′(x )＝4ax 3＋2cx ，当x ＝1时，f ′(1)＝4a ＋2c ＝－2， ①对于2x ＋y －2＝0，当x ＝1时，y ＝0.∴点(1,0)在f (x )图象上，∴a ＋c －1＝0. ②由①②解得a ＝－2，c ＝3，因此f (x )＝－2x 4＋3x 2－1.16．已知曲线C 1：y ＝x 2与C 2：y ＝－(x －2)2，直线l 与C 1，C 2都相切，求直线l 的方程．设l 与C 1相切于点P (x 1，x 21)，与C 2相切于点Q (x 2，－(x 2－2)2)．对C 1：y ′＝2x ，则与C 1相切于点P 的切线方程为y －x 21＝2x 1(x－x 1)，即y ＝2x 1x －x 21. ①对C 2：y ′＝－2(x －2)，则与C 2相切于点Q 的切线方程为y ＋(x 2－2)2＝－2(x 2－2)(x －x 2)，即y ＝－2(x 2－2)x ＋x 22－4.② ∵两切线重合，∴⎩⎨⎧ 2x 1＝－2(x 2－2)－x 21＝x 22－4，解得⎩⎨⎧ x 1＝0x 2＝2或⎩⎨⎧ x 1＝2x 2＝0，∴直线方程为y ＝0或y ＝4x －4.。
人教版数学高二-课时作业 2-1第1课时 数列的概念与通项公式
第2章 2.1 第1课时(本栏目内容，在学生用书中以活页形式分册装订！)一、选择题(每小题5分，共20分)1．已知数列的通项公式：a n ＝⎩⎪⎨⎪⎧3n ＋1n 为奇数，2n －2n 为偶数，则a 2·a 3等于( )A ．70B ．28C ．20D ．8解析： a 2＝2 2－2＝2a 3＝3 3＋1＝10 a 2·a 3＝20.故选C.答案： C2．已知a n ＝n 2＋n ，那么( ) A ．0是数列中的项 B ．20是数列中的项 C ．3是数列中的项D ．930不是数列中的项解析： 令n 2＋n ＝0，得n ＝0或n ＝－1，∵n ∉N *，故A 错． 令n 2＋n ＝20，即n 2＋n －20＝0，∴n ＝4或n ＝－5(舍)， ∴a 4＝20.故B 正确． 令n 2＋n ＝3，即n 2＋n －3＝0.∴Δ＝1－4 (－3)＝13，故无有理根，C 错． 令n 2＋n ＝930，即(n ＋31)(n －30)＝0， ∴n ＝30或n ＝－31(舍)，∴a 30＝930，故D 错． 答案： B3．设数列2，5，22，11，⑤则25是这个数列的( ) A ．第6项 B ．第7项 C ．第8项D ．第9项解析： 该数列通项公式为a n ＝3n －1. 令3n －1＝25，得n ＝7. 答案： B4．数列－1，43，－95，167，⑤的一个通项公式是( )A ．a n ＝(－1)nn 22n －1B ．a n ＝(－1)nn n ＋12n －1C ．a n ＝(－1)nn 22n ＋1D ．a n ＝(－1)nn 3－2n2n －1解析： 分子为1、4、9、16、⑤、n 2.分母为1、3、5、7、⑤、(2n －1)，又奇数项为负，偶数项为正，故选A.答案： A二、填空题(每小题5分，共10分)5．数列35，12，511，37，⑤的一个通项公式是________．解析： 数列可写为：35，48，511，614，⑤，分子满足：3＝1＋2,4＝2＋2,5＝3＋2,6＝4＋2，⑤，分母满足：5＝3 1＋2,8＝3 2＋2,11＝3 3＋2,14＝3 4＋2，⑤，故通项公式为a n ＝n ＋23n ＋2.答案：n ＋23n ＋26．在数列－1,0，19，18，⑤，n －2n2，⑤中，0.08是它的第______项．解析： 令n －2n2＝0.08，得2n 2－25n ＋50＝0， 即(2n －5)(n －10)＝0. 解得n ＝10或n ＝52(舍)．∴a 10＝0.08. 答案： 10三、解答题(每小题10分，共20分)7．已知有限数列45，910，1617，2526，⑤，m 2m 2＋1(m ♏7)．(1)指出这个数列的一个通项公式；(2)判断0.98是不是这个数列中的项？若是，是第几项？ 解析： (1)由观察知数列的通项公式不是m 2m 2＋1.又∵数列的分子依次为4,9,16,25，⑤可看成与项数n 的关系式为(n ＋1)2，而每一项的分母恰好比分子大1，∴通项公式的分母可以为(n ＋1)2＋1. ∴数列的一个通项公式为a n ＝n ＋12n ＋12＋1(n ＝1,2，⑤，m －1)．(2)由(1)知数列的通项公式a n ＝n ＋12n ＋12＋1，不妨设0.98是这个数列的第n 项，即n ＋12n ＋12＋1＝0.98，解得n ＝6∈N *， ∴0.98是数列中的第6项．8．已知数列{a n }的通项公式为a n ＝n 2－5n ＋4. (1)数列中有多少项是负数？(2)n 为何值时，a n 有最小值？并求出最小值． 解析： (1)由n 2－5n ＋4<0，解得1<n <4. ∵n ∈N *，∴n ＝2,3. ∴数列有两项是负数．(2)方法一：∵a n ＝n 2－5n ＋4＝⎝ ⎛⎭⎪⎫n －522－94，可知对称轴方程为n ＝52＝2.5.又因n ∈N *，故n ＝2或3时，a n 有最小值，其最小值为 22－5 2＋4＝－2. 方法二：设第n 项最小，由⎩⎪⎨⎪⎧a n ♎a n ＋1，a n ♎a n －1，得⎩⎪⎨⎪⎧n 2－5n ＋4♎n ＋12－5n ＋1＋4，n 2－5n ＋4♎n －12－5n －1＋4.解这个不等式组得2♎n ♎3， ∴n ＝2,3， ∴a 2＝a 3且最小，∴a 2＝a 3＝22－5 2＋4＝－2. 尖子生题库☆☆☆9．(10分)如图所示，有n (n ♏2)行(n ＋1)列的士兵方阵：(1)写出一个数列，用它表示当n分别为2,3,4,5,6，⑤时方阵中的士兵人数；(2)说出(1)中数列的第5,6项，用a5，a6表示；(3)若把(1)中的数列记为{a n}，求该数列的通项公式a n；(4)求a10，并说明a10所表示的实际意义．解析：(1)当n＝2时，表示士兵的人数为2行3列，人数为6；当n＝3时，表示3行4列，人数为12，依此类推，故所求数列为6,12,20,30，⑤.(2)方阵的行数比数列的序号大1，因此第5项表示的是6行7列，第6项表示的是7行8列，故a5＝42，a6＝56.(3)根据对数列的前几项的观察，归纳、猜想数列的通项公式．项：6＝2 3,12＝3 4,20＝4 5,30＝5 6❽❽❽❽序号： 1 23 4因此a n＝(n＋1)(n＋2)．(4)由(3)知a10＝11 12＝132，a10表示11行12列的士兵方阵中士兵的人数．。
2021-2022学年新教材人教A版数学必修第一册课时作业：2
课时作业(十二) 基本不等式[练基础]1．不等式a 2＋1≥2a 中等号成立的条件是( ) A ．a ＝±1 B ．a ＝1 C ．a ＝－1 D ．a ＝0 2．若a ≥0，b ≥0且a ＋b ＝2，则( )A ．ab ≤12B ．ab ≥12C ．a 2＋b 2≥2D ．a 2＋b 2≤33．“a ，b 为正数”是“a ＋b >2ab ”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4．设x >0，则y ＝3－3x －1x的最大值是( )A ．3B ．3－22C ．3－23D ．－15．已知x >0，y >0，且2x ＋y ＝1，则xy 的最大值是( ) A.14B ．4C.18D ．8 6．(多选)设a ，b ∈R ，则下列不等式一定成立的是( )A ．a 2＋b 2≥2abB ．a ＋1a ≥2C ．b 2＋1≥2b D.⎪⎪⎪⎪b a ＋⎪⎪⎪⎪a b ≥27．若a ＜1，则a ＋1a －1与－1的大小关系是________．8．已知正数x ，y 满足x ＋2y ＝2，则1y ＋8x 的最小值为________．9．已知a >b >c ，你能比较出4与⎝⎛⎭⎫1a －b ＋1b －c (a －c )的大小吗？10．(1)若x ＜3，求y ＝2x ＋1＋1x －3的最大值；(2)已知x ＞0，求y ＝2xx 2＋1的最大值．[提能力]11．(多选)下列命题中正确的是( )A ．y ＝x ＋1x ()x <0的最大值是－2B ．y ＝x 2＋3x 2＋2的最小值是2C ．y ＝2－3x －4x ()x >0的最大值是2－4 3D ．y ＝x ＋4x －1()x >1最小值是5 12．(多选)下列结论正确的是( )A ．若x <0，则y ＝x ＋1x的最大值为－2B ．若a >0，b >0，则ab ≤⎝⎛⎭⎫a ＋b 22C ．若a >0，b >0，且a ＋4b ＝1，则1a ＋1b的最大值为9D ．若x ∈[]0，2，则y ＝x 4－x 2的最大值为213．已知x >0，y >0，且x ＋2y ＝3，则xy 的最大值为________，3x ＋yxy的最小值为________．14．已知5x 2y 2＋y 4＝1()x ，y ∈R ，则x 2＋2y 2的最小值是________．15．已知正常数a ，b 和正变数x ，y 满足a ＋b ＝10，a x ＋by＝1，x ＋y 的最小值为18，求a ，b 的值．[培优生]16．《几何原本》中的几何代数法(以几何方法研究代数问题)成了后世数学家处理问题的重要依据．通过这一原理，很多的代数的公理或定理都能够通过图形实现证明，也称之为无字证明．如图，在AB 上取一点C ，使得AC ＝a ，BC ＝b ，过点C 作CD ⊥AB 交半圆周于点D ，连接OD .作CE ⊥OD 交OD 于点E .由CD ≥DE 可以直接证明的不等式为( )A.ab ≥2aba ＋b(a >0，b >0)B.a ＋b 2≥ab (a >0，b >0)C.a 2＋b 22≥a ＋b 2(a >0，b >0)D ．a 2＋b 2≥2ab (a >0，b >0)课时作业(十二) 基本不等式1．解析：当a 2＋1＝2a ，即(a －1)2＝0， 即a ＝1时，等号成立．故选B. 答案：B2．解析：因为a 2＋b 2≥2ab ，所以(a 2＋b 2)＋(a 2＋b 2)≥(a 2＋b 2)＋2ab ， 即2(a 2＋b 2)≥(a ＋b )2＝4，所以a 2＋b 2≥2.故选C. 答案：C3．解析：若a ，b 为正数，取a ＝1，b ＝1，则a ＋b ＝2ab ，则“a ，b 为正数”不是“a ＋b >2ab ”的充分条件；若a ＋b >2ab ，取a ＝1，b ＝0，则b 不是正数，则“a ，b 为正数”不是“a ＋b >2ab ”的必要条件．故“a ，b 为正数”是“a ＋b >2ab ”的既不充分也不必要条件．故选D.答案：D4．解析：y ＝3－3x －1x ＝3－⎝⎛⎭⎫3x ＋1x ≤3－23x ·1x ＝3－23，当且仅当3x ＝1x ，即x ＝33时取等号．故选C.答案：C5．解析：由题意得，xy ＝12×2xy ≤12×⎝⎛⎭⎫2x ＋y 22＝12×⎝⎛⎭⎫122＝18，当且仅当x ＝14，y ＝12时等号成立，所以xy 的最大值是18.故选C.答案：C6．解析：当a ，b ∈R 时，a 2＋b 2≥2ab 成立，故A 正确；当a ＞0时，a ＋1a≥2，等号成立的条件是a ＝1，当a ＜0时，a ＋1a≤－2，等号成立的条件是a ＝－1，故B 不正确；当b ∈R 时，b 2＋1－2b ＝(b －1)2≥0，所以b 2＋1≥2b ，故C 正确；⎪⎪⎪⎪b a ＞0，⎪⎪⎪⎪a b ＞0，所以⎪⎪⎪⎪b a ＋⎪⎪⎪⎪a b ≥2⎪⎪⎪⎪b a ×⎪⎪⎪⎪a b ＝2，等号成立的条件是当且仅当⎪⎪⎪⎪b a ＝⎪⎪⎪⎪a b ，即a 2＝b 2时，故D 正确．故选ACD.答案：ACD7．解析：因为a ＜1，即1－a >0，所以－⎝⎛⎭⎫a －1＋1a －1＝(1－a )＋11－a ≥2(1－a )·11－a＝2.即a ＋1a －1≤－1. 答案：a ＋1a －1≤－18．解析：因为x >0，y >0且x ＋2y ＝2，所以1y ＋8x ＝x ＋2y 2y ＋4x ＋8yx＝5＋x 2y ＋8y x ≥5＋2x 2y ·8y x ＝9(当且仅当x 2y ＝8y x ，即x ＝4y ＝43时取等号)，即1y ＋8x的最小值为9.答案：99．解析：⎝⎛⎭⎫1a －b ＋1b －c (a －c )≥4，理由如下：因为a －c ＝(a －b )＋(b －c )，所以⎝⎛⎭⎫1a －b ＋1b －c [(a －b )＋(b －c )]＝2＋b －c a －b ＋a －b b －c，又a >b >c ，所以b －c a －b ＋a －bb －c≥2，故⎝⎛⎭⎫1a －b ＋1b －c (a －c )≥4， 当且仅当b －c a －b ＝a －bb －c时，取“＝”．10．解析：(1)因为x ＜3，所以3－x ＞0.又因为y ＝2(x －3)＋1x －3＋7＝－⎣⎡⎦⎤2(3－x )＋13－x ＋7，由基本不等式可得2(3－x )＋13－x ≥22(3－x )·13－x ＝22，当且仅当2(3－x )＝13－x，即x ＝3－22时，等号成立，于是－⎣⎡⎦⎤2(3－x )＋13－x ≤－22，－⎣⎡⎦⎤2(3－x )＋13－x ＋7≤7－22，故y 的最大值是7－2 2.(2)y ＝2x x 2＋1＝2x ＋1x.因为x ＞0，所以x ＋1x ≥2x ·1x ＝2，所以0＜y ≤22＝1，当且仅当x＝1x，即x ＝1时，等号成立．故y 的最大值为1. 11．解析：对于A ，y ＝x ＋1x ＝－⎝⎛⎭⎫－x －1x ≤－2－x ·⎝⎛⎭⎫－1x ＝－2，当且仅当－x ＝－1x，即x ＝－1时，等号成立，所以y ＝x ＋1x ()x <0的最大值是－2，故A 正确；对于B ，y ＝x 2＋3x 2＋2＝x 2＋2＋1x 2＋2>2，因为x 2＋2＝1x 2＋2，即x 2＋2＝1无解，即等号不成立，所以y ＝x 2＋3x 2＋2取不到最小值2，故B 错误；对于C ，y ＝2－3x －4x (x >0)＝2－(3x ＋4x )≤2－23x ·4x ＝2－43，当且仅当3x ＝4x ，即x ＝233时，等号成立，所以y ＝2－3x －4x(x >0)的最大值是2－43，故C 正确；对于D ，y ＝x ＋4x －1＝x －1＋4x －1＋1≥2()x －1·4x －1＋1＝5，当且仅当x －1＝4x －1，即x ＝3时，等号成立，所以y ＝x ＋4x －1()x >1最小值是5，故D 正确；故选ACD.答案：ACD12．解析：A 选项，由x <0可得y ＝x ＋1x ＝－⎣⎡⎦⎤()－x ＋⎝⎛⎭⎫－1x ≤－2()－x ·⎝⎛⎭⎫－1x ＝－2，当且仅当－x ＝－1x，即x ＝－1时，等号成立；即y ＝x ＋1x 的最大值为－2；A 正确；B 选项，由a >0，b >0，可得⎝⎛⎭⎫a ＋b 22－ab ＝a 2＋b 2－2ab 4＝⎝⎛⎭⎫a －b 22≥0，即ab ≤⎝⎛⎭⎫a ＋b 22，故B 正确；C 选项，若a >0，b >0，且a ＋4b ＝1，则1a ＋1b ＝⎝⎛⎭⎫1a ＋1b ()a ＋4b ＝1＋4b a ＋a b ＋4≥5＋24b a ·a b ＝9，当且仅当4b a ＝a b ，即⎩⎨⎧a ＝13b ＝16时，等号成立；即1a ＋1b 的最小值为9，故C 错；D 选项，因为0≤x ≤2，所以y ＝x4－x 2≤x 2＋()4－x 22＝2，当且仅当x ＝4－x 2，即x ＝2时，等号成立，故D 正确．故选ABD.答案：ABD13．解析：∵x >0，y >0∴x ＋2y ＝3≥22xy ，解之得：xy ≤98.当且仅当x ＝2y ，即x ＝32，y ＝34时，等号成立．∴xy 的最大值为98.3x ＋y xy ＝3y ＋1x ＝13()x ＋2y ⎝⎛⎭⎫3y ＋1x ＝73＋13⎝⎛⎭⎫3x y ＋2y x ≥73＋233x y ·2y x ＝7＋263.当且仅当3x y ＝2yx ，即x ＝36－35，y ＝18－3610时，等号成立．∴3x ＋y xy 的最小值为7＋263.另解：∵x >0，y >0，且x ＋2y ＝3∴x ＝3－2y >0，∴0<y <32.∴xy ＝y ()3－2y ＝－2y 2＋3y ＝－2⎝⎛⎭⎫y －342＋98. ∵0<y <32，∴当y ＝34时，()xy max ＝98，此时x ＝32.答案：98 7＋26314．解析：∵5x 2y 2＋y 4＝1∴y ≠0且x 2＝1－y 45y 2∴x 2＋2y 2＝1－y 45y 2＋2y 2＝15y 2＋9y 25≥215y 2·9y 25＝65，当且仅当15y 2＝9y 25，即x 2＝815，y 2＝13时取等号．∴x 2＋y 2的最小值为65.答案：6515．解析：因为x ＋y ＝(x ＋y )·1＝(x ＋y )·⎝⎛⎭⎫a x ＋b y ＝a ＋b ＋ay x ＋bxy ≥a ＋b ＋2ab ＝(a ＋b )2，当且仅当ay x ＝bxy，即y x ＝b a时，等号成立， 所以x ＋y 的最小值为(a ＋b )2＝18， 又a ＋b ＝10，所以ab ＝16.所以a ，b 是方程x 2－10x ＋16＝0的两根， 所以a ＝2，b ＝8或a ＝8，b ＝2. 16．解析：由三角形相似，知CD 2＝DE ·OD ＝AC ·BC ，即DE ＝DC 2OD ＝ab a ＋b 2＝2aba ＋b，由CD ≥DE ，得ab ≥2aba ＋b，故选A.答案：A。
2019_2020学年新教材高中英语Unit4FriendsforeverPeriod2课时作业(二)外研版必修第一册
Period 2 Understanding ideas课时作业(二)[基础训练]Ⅰ单词拼写1．I am going to buy a ________ (数字的) camera for my friend who likes taking photos.答案：digital2．Leaflets have been ________ (递送) to every household.答案：delivered3．I would ________ (更喜欢) it if you didn't tell anyone.答案：prefer4．My old friend Jack and I have always ________ (保持，维持) close relations.答案：maintained5．I have a good command of oral English, which ________ (使能够) me to hold the position.答案：enablesⅡ单句语法填空1．It's cheaper if you book the tickets ________ advance.答案：in in advance固定短语，意为“提前，预先”。
2．It must be kept ________ mind that there is no secret of success but hard work.答案：in keep ... in mind固定短语，意为“牢记”。
3．The number of local people now supporting him has increased ________ (significant)．答案：significantly 所填词修饰句子的谓语动词has increased，应用副词，故填significantly。
湘教版数学九年级上册_课时作业：第2课时_图形面积和动点问题
2.5第2课时图形面积和动点问题一、选择题1．王叔叔从市场上买了一块长80 cm、宽70 cm的矩形铁皮，准备制作一个工具箱．如图，他将矩形铁皮的四个角各剪掉一个边长为x cm的正方形后，剩余的部分刚好能围成一个底面积为3000 cm2的无盖长方体工具箱，根据题意可列方程为()A．(80－x)(70－x)＝3000B．80×70－4x2＝3000C．(80－2x)(70－2x)＝3000D．80×70－4x2－(70＋80)x＝30002．如图，在宽为20米，长为30米的矩形地面上修建两条同样宽的道路，余下部分作为耕地．若耕地面积需要551平方米，则修建的路宽应为()A．1米B．1.5米C．2米D．2.5米3．如图，将边长为2 cm的正方形ABCD沿其对角线AC剪开，再把△ABC沿着AD方向平移，得到△A′B′C′.若两个三角形重叠部分的面积为 1 cm2，则它移动的距离AA′的值为()A．0.5 cm B．1 cm C．1.5 cm D．2 cm4．如图，在△ABC中，AC＝50 cm，BC＝40 cm，∠C＝90°，点P从点A开始沿AC边向点C以2 cm/s的速度匀速移动，同时另一点Q由点C开始以3 cm/s的速度沿着射线CB 匀速移动，当△PCQ的面积等于300 cm2时，运动时间为()A．5 s B．20 s C．5 s或20 s D．不确定二、填空题5．如图，用长度为32米的篱笆，一面利用墙(墙的最大可用长度为16米)，围成一个面积为120平方米的长方形花圃．若设BC的长为x米，则根据条件能得到一个关于x的一元二次方程，该方程的一般形式为______________．(不用写出x的取值范围)6．如图所示，在Rt△ABC中，∠BAC＝90°，AB＝AC＝16 cm，AD为BC边上的高，动点P从点A出发，沿AD方向以 2 cm/s的速度向点D运动．E为AC边上一点．设△ABP 的面积为S1，矩形PDFE的面积为S2，运动时间为t s，则t＝________时，S1＝2S2.三、解答题7．如图①，要设计一幅宽20 cm、长30 cm的矩形图案，其中有两横两竖的彩条，横、竖彩条的宽度比为2∶3.如果要使所有彩条所占面积为原矩形图案面积的三分之一，应如何设计每个彩条的宽度？分析：由横、竖彩条的宽度比为2∶3，可设每个横彩条的宽为2x cm，则每个竖彩条的宽为3x cm.为更好地寻找题目中的等量关系，将横、竖彩条分别集中，原问题转化为如图②的情况，得到矩形ABCD.(1)如图②，用含x的代数式表示：AB＝________cm，AD＝________cm，矩形ABCD的面积为_______________cm2；(2)列出方程并完成本题解答．8.图是一幅长20 cm 、宽12 cm 的图案，其中有一横两竖的彩条，横、竖彩条的宽度比为3∶2.设竖彩条的宽度为x cm ，图案中三条彩条所占面积为y cm 2.(1)试用含有x 的代数式表示y ，并确定x 的取值范围；(2)若图案中三条彩条所占面积是图案面积的25，求横、竖彩条的宽度．9．如图，在△ABC 中，∠B ＝90°，AB ＝6 cm ，BC ＝3 cm ，点P 从点A 开始沿AB 边向点B 以2 cm/s 的速度移动，点Q 从点B 开始沿BC 边向点C 以1 cm/s 的速度移动，如果P ，Q 两点同时出发，点P 运动到C 时，P ，Q 两点同时停止运动．(1)几秒钟后，△APQ 是等腰三角形？(2)几秒钟后，△BPQ 的面积是四边形CQP A 的面积的1310．李明准备进行如下试验操作：把一根长40 cm 的铁丝剪成两段，并把每段首尾相连各围成一个正方形．(1)要使这两个正方形的面积之和等于58 cm 2，李明应该怎么剪这根铁丝？(2)李明认为这两个正方形的面积之和不可能等于48 cm 2，你觉得他的想法正确吗？请说明理由．方案设计某小区计划在一块长100 m 、宽60 m 的矩形荒地上修建一个配绿化带的活动区，要求整体布局既是轴对称图形，又是中心对称图形，且绿化率不低于35%(绿化率＝绿化面积总面积×100%)．(1)甲方案：如图①所示，设计两条互相垂直且宽度都为a m 的十字活动区域，周边四块为绿化带(图中阴影部分)，若绿化面积为2100 m 2，求a 的值；(2)乙方案：如图K －16－10②所示(单位：m)，场地正中央设计菱形绿化带(图中阴影部分)，周边为活动区域，请通过计算说明该方案是否符合要求．详解详析[课堂达标] 1．[答案] C2．[解析] A 设修建的路宽为x m ．依题意，得(30－x)(20－x)＝551， 解得x 1＝1，x 2＝49(不合题意，舍去)．3．[解析] B 设AC 交A′B′于点H.∵∠A ＝45°，∠AA′H ＝90°，∴△A′HA 是等腰直角三角形．设AA′＝x cm ，则阴影部分的底A′H 的长为x cm ，高A′D ＝(2－x)cm ，∴x·(2－x)＝1，∴x 1＝x 2＝1，即AA′＝1 cm .4．[解析] C 设运动时间为t s ，则AP ＝2t ，CQ ＝3t ，∴PC ＝50－2t.∵12·PC·CQ ＝300，∴12·(50－2t)·3t ＝300，解得t ＝20或t ＝5，∴运动时间为20 s 或5 s 时，△PCQ 的面积等于300 cm 2.故选C .5．[答案] x 2－32x ＋240＝0[解析] 依题意得12(32－x)x ＝120.整理，得x 2－32x ＋240＝0.6．[答案] 6[解析] ∵在Rt △ABC 中，∠BAC ＝90°，AB ＝AC ＝16 cm ，AD 为BC 边上的高， ∴AD ＝BD ＝CD ＝8 2 cm .又∵AP ＝2t cm ，则S 1＝12AP·BD ＝12×2×8 2t ＝8t ，PD ＝(8 2－2t)cm .∵PE ∥BC ，∴∠AEP ＝∠C ＝45°，∠APE ＝∠ADC ＝90°， ∴∠PAE ＝∠AEP ＝45°，∴PE ＝AP ＝2t cm ，∴S 2＝PD·PE ＝(8 2－2t)·2t.∵S 1＝2S 2，∴8t ＝2(8 2－2t)·2t ，解得t ＝6或t ＝0(舍去)．故答案是6.7．[解析] 读懂题中的分析，利用已有的数量关系与面积公式列方程． 解：(1)(20－6x)(30－4x) (20－6x)(30－4x) (2)根据题意，得(20－6x)(30－4x)＝(1－13)×20×30.整理，得6x 2－65x ＋50＝0，解得x 1＝56，x 2＝10(不合题意，舍去)，则2x ＝53，3x ＝52.答：每个横、竖彩条的宽度分别为53 cm ，52 cm .8．解：(1)根据题意可知，横彩条的宽度为32x cm ，∴⎩⎪⎨⎪⎧x>0，20－2x>0，12－32x>0，解得0＜x ＜8.y ＝20×32x ＋2×12·x －2×32x·x ＝－3x 2＋54x ，即y ＝－3x 2＋54x(0＜x ＜8)．(2)根据题意，得－3x 2＋54x ＝25×20×12，整理，得x 2－18x ＋32＝0， 解得x 1＝2，x 2＝16(舍去)，∴32x ＝3.答：横彩条的宽度为3 cm ，竖彩条的宽度为2 cm . 9．解：设运动时间为t s ，则AP ＝2t ，BP ＝6－2t ，BQ ＝t. (1)∵∠B ＝90°，∴∠APQ ＞90°. ∵△APQ 是等腰三角形，∴AP ＝PQ ，即2t ＝（6－2t ）2＋t 2，解得t 1＝12－6 3，t 2＝12＋6 3＞3(不合题意，舍去)．答：(12－6 3)s 后，△APQ 是等腰三角形．(2)△BPQ 的面积是四边形CQPA 的面积的13，即△BPQ 的面积等于△ABC 面积的14.∵S △BPQ ＝12BP·BQ ＝12(6－2t)t ＝3t －t 2，S △ABC ＝12AB·BC ＝9，∴3t －t 2＝94，即t 2－3t ＋94＝0，解得t 1＝t 2＝32.答：32s 后，△BPQ 的面积是四边形CQPA 的面积的13.11．解：(1)设剪成的较短的铁丝长为x cm ，则较长的铁丝长为(40－x)cm . 由题意，得⎝⎛⎭⎫x 42＋⎝⎛⎭⎫40－x 42＝58， 解得x 1＝12，x 2＝28， 当x ＝12时，40－12＝28(cm )，当x ＝28时，40－28＝12(cm )＜28 cm (舍去)．答：李明应该把铁丝剪成12 cm 和28 cm 的两段．(2)正确．理由：设剪成的较短的铁丝长为m cm ，则较长的铁丝长为(40－m)cm ， 由题意，得⎝⎛⎭⎫m 42＋⎝⎛⎭⎫40－m 42＝48. 整理，得m 2－40m ＋416＝0. ∵Δ＝(－40)2－4×416＝－64＜0， ∴原方程无实数根，∴这两个正方形的面积之和不可能等于48 cm 2，即李明的想法正确． [素养提升]解：(1)依题意有(100－a)(60－a)＝2100， 解得a 1＝30，a 2＝130(不合题意，舍去)． 答：a 的值是30.(2)100－5×2＝100－10＝90(m )， 60－5×2＝60－10＝50(m )， 90×50÷2＝2250(m 2)， 100×60＝6000(m 2)， 22506000×100%＝37.5%. ∵37.5%＞35%， ∴该方案符合要求．。
高中英语课时作业二Unit1ANewStartSectionⅡUsinglangua外研版必修第一册
课时作业(二) Unit 1 Section Ⅱ Using language 语言知识训练Ⅰ.单词拼写1．I've heard that you are a talented young woman, and I have found you charming and i________ (聪明的) as well.2．T o get the most out of reading these plays, try to picture the play on s________ (舞台), with you, the reader, in the audience.3．Y ou can be the one who directs the conversation to fun t________ (话题) that are ripe for others to add humor.4．If you take the trouble to s________ (安排) a visit, you can be more or less guaranteed of a response.5．The musician along with his b________ (乐队) members has given ten performances in the last three months.6．Unlike traditional gyms, appbacked g________ (健身房) offer people flexible options to exercise.7．Being very interested in your English drama club when I saw your p________ (海报), I would like to join the big family.8．I am so glad to have the chance to join the d________ (讨论). Now I want to say something about garbage classification.9．I'm more than glad to have been invited to attend the p________ (钢琴) concert with you.10．When he heard these words, my father felt his i________ (内心的) doubts melt away.Ⅱ.请选用所给短语的适当形式填空look after, play a part in, argue about, come along, care about, such as, twice a month, take part in1.For 10 years she ____________ her three children with her career very much on the back burner.2．He and his sister always ____________ politics.3．I'm so stupid. I shouldn't have ____________ with you to this place.4．He goes backwards and forwards between Dalian and Shanghai ____________．5．His toes are hurt and he is unable to ____________ today's basketball game.6．He bought a lot of fruit ____________ apples and peaches.7．The famous writer neither worried nor ____________ public opinion.8．The agriculture during the19th century____________the early industrialization of the United States.Ⅲ.单句语法填空1．The street was crowded with reporters, ________ (photograph), cameras and microphones.2．It's ________ (argue) whether the plan is actually worthwhile.3．The pencil case contains pencils, a pencil ________ (sharp) and an eraser.4．A workman must ________ (sharp) his tools if he is to do his work well.5．I believe that the science of artificial ________ (intelligent) is waiting for humanity to explore it step by step.6．Reading books is learning; ________ (apply) is also learning and the more important form of learning.7．It's not right to make a decision without ________ (investigate) and study.8．With the development of industry,people's material wealth and lifestyle changed ________ (drama) .9．In the UK and US, senior high school students take part in ________ (vary) afterschool activities.10．In the mid1990s，T om Bissell taught English as ________ volunteer in Uzbekistan.Ⅳ.写出下列句子的句型结构1．James is an exchange student.________________________________________________________________________ 2．Y ou should register before Friday.________________________________________________________________________ 3．The traffic light is flashing.________________________________________________________________________ 4．His words gave me more confidence.________________________________________________________________________ 5．I found her an outgoing and kind girl.________________________________________________________________________ 6．The boy was reading a story in a loud voice.________________________________________________________________________ 7．The designer designed a beautiful dress.________________________________________________________________________ 8．They argued fiercely.________________________________________________________________________ 9．The new student looks anxious and frightened.________________________________________________________________________ 10．Planting trees is important especially in mountainous areas.________________________________________________________________________ 语言能力训练Ⅰ.阅读理解Although toys'packaging says it's educational,it doesn't make it so. That's the finding from a new study in JAMA Pediatrics that found some toys being marketed as language promoters got in the way of learning.Research shows that for kids to understand, speak and eventually read or write a language, they need to hear it—lots of it. And it's never too early for parents and caregivers to get talking. That explains the fast industry in talking electronic toys that claim to help kids learn language.“We had a talking on farmanimal names and things，”Professor Anna Sosa says of the electronic toys. “We had a baby cell phone. And we had a baby laptop. So you open the cover and start pushing buttons, and it tells you things. The parentchild couples were asked to play separately with each type of toy over the course of three days.”“When there's something else that's doing some talking,the parents seem to be sitting on the sidelines and letting the toy talk for them and respond for them，” Sosa says. “That's bad because the best way a toy can promote language in babies and kids is by exciting interaction between parent and child. There's simply no evidence that a young child can learn language directly from a toy. It isn't responsive enough. It isn't social.”As for the other toys, traditional blocks and puzzles stimulated more conversation than the electronic toys,and books outscored them all. But don't underestimate the humble block. “While traditional toys fell short of books in interaction quantity，”Sosa notes, “they kept pace in terms of quality.”1．What is the finding of the research led by Professor Anna Sosa?A．The toy industry is facing new challenges in marketing.B．Kids should be taught to learn with toys as early as possible.C．People might be misled by the statements of some toy makers.D．Parents need to be cautious when choosing toys for their kids.2．According to the passage, why are talking electronic toys so popular?A．Because they represent the latest creations.B.Because they arouse the interest in learning.C.Because they are used as an educational tool.D.Because they are easy for the kids to control.3．What can we infer from the fourth paragraph?A.It is necessary for the parents to share their experiences of reading with their kids.B. It is necessary for the parents to spare more time to stay with their kidsat home.C．It is necessary for the parents to encourage their kids to attend social activities.D．It is necessary for the parents to get involved in the conversations with their kids.4．What is the author's attitude to electronic toys as language promoters?A．Critical. B．Doubtful.C．Supportive. D．Objective.Ⅱ.七选五How to Be a Good Listener in ClassBeing a good student means being a good listener.Whether you're a young student or entering college, it's important to learn to pay attention in class and take good notes, which will help you succeed.__1__.Be prepared for classWhen it's time to go to class, make sure you've got everything that you need ready to go,so you won't have to miss anything because you're struggling to catch up.__2__. In general, you want to make sure you have, for each class:notebooks,pencils already sharpened or pens that work well, books needed for class.Look at the teacher__3__.When your teacher is talking, your eyes should be to the front. Don't look out the window, or at the kids next to you, or at the phone you're trying to hide under your desk. Look at your teacher and what is being presented.__4__Concentrate on understanding the broad concepts, and don't try to catch every single word.Listen for key words and concepts that your teacher mentions, and pay attention to what's written on the board. Anything that the teacher takes the time to write down on the board is extremely important. Also, anything that is repeated several times is very important.T ake good notesHave a different notebook for each class, and have some pencils or pens ready to go when you want to take notes.__5__. It's not necessary to have a total record of everything your teacher says. As long as you try to keep up and write down important ideas, taking notes is a good way of paying attention in class.A．Listen to important ideasB．Remember what you hearC．Only write down key wordsD．Good listening starts with good watchingE．Have good notetaking materials ready to go while in classF．Learn to listen well and set yourself up for success by staying focused G．Y ou'll miss part of a lecture if you're trying to finish your homework before class starts课时作业(二)层级一 语言知识训练Ⅰ.单词拼写1．intelligent 2.stage 3.topics 4.schedule 5.band6．gyms 7.poster 8.debate 9.piano 10.innerⅡ.请选用所给短语的适当形式填空1．has looked after 2.argue about e along 4.twice a month 5.take part in 6.such as 7.cared about 8.played a part inⅢ.单句语法填空1．photographers 2.arguable 3.sharpener 4.sharpen 5.intelligence 6.application 7.investigation 8.dramatically 9.various 10.aⅣ.写出下列句子的句型结构1．JamesS __is__V an__exchange__student.P2．Y ouS should__registerV before__Friday.A3．The__traffic__lightS is__flashing.V4．His__wordsS gaveV me__IO more__confidence.DO5．IS foundV herO an__outgoing__and__kind__girl.OC6．The__boyS was__readingV a__storyO in__a__loud__voice.A7．The__designerS designedV a__beautiful__dress.O8．TheyS arguedV fiercely.A9．The__new__studentS looksV anxious__and__frightened.P10．Planting__treesS is__V importantP especially__in__mountainous__areas.A层级二 语言能力训练Ⅰ.阅读理解【语篇解读】 本文是一篇议论文。
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(必修一·Unit 2)Ⅰ.单项填空1．I wouldn't marry Pat even if she ________ the last woman on earth.A．is B．wasC．had been D．were答案：D2．You can't do ________ your friends ask you to do.You'd better think first.A．everything B．anythingC．something D．nothing答案与解析：A考查不定代词辨析。
句意为：你不能做朋友让你做的每一件事件，你最好首先考虑一下。
not...everything表示部分否定。
3．It's so nice to hear from her again.________，we last met more than fifteen years ago.A．What's more B．That's to sayC．In other words D．Believe it or not答案：D4．It is requested that the reporter ________ to blame for the wrong report.A．referring to B．referring to asC．referred to be D．referred to being答案与解析：C当在复合句中出现表示“建议、主张或命令”的动词时，该从句应该使用虚拟语气，should常可省略；refer red to为过去分词短语作定语。
5．Whoever has ridden on a railway train knows how rapidly another train flashes by when it is traveling ________ the opposite direction.A．in B．underC．to D．with答案与解析：A direction常与in搭配，意为“朝……方向”。
6．You type almost anything，however unclear，into the space provided on Google and in a second it ________ with thousands of references.A catches up B．comes upC．ends up D．puts up答案与解析：B come up“出现”，相当于appear，与题意相符。
catch up“追上；赶上”；end up“结束”；put up“举起”。
7．When I began working ten years ago，I just earned too little to cover my living ________.A．bills B．pricesC．change D．expense答案与解析：D expense侧重指日常开支所需的“开支；费用”。
bill“账单”；price“价格”；change“零钱”。
8．Many students make great progress in listening ________ the large amount of time devoted to it.A．because of B．instead ofC．in case of D．in spite of答案与解析：A because of“因为，由于”，后接名词短语在句中作原因状语，此处表示“在听力方面取得巨大进步的原因”。
9．—Jim has his wife do all the housework！Isn't he wise?—Not really.He is ________.A．more wise than lazy B．wiser than lazyC．more lazy than wise D．laziest than wise答案与解析：C more...than...常用来对不同的人或事情的同一性质或方面的比较，后接两个对等成分，more后的形容词词尾不变，意为“与其说……不如说……”。
10．Some languages，________ Russian and German，are not easy to learn.A．for example B．such asC．namely D．that is答案与解析：B such as列举同类事物中的一部分，意为“例如”。
for example也用来举例说明，但其前后常用逗号隔开；namely相当于that is，意为“即”。
11．We can see monuments here and there.Those who have made great ________ to human beings and society will never be forgotten.A．advance B．progressC．contribution D．achievement答案与解析：C make contribution to为固定短语，意为“对……做出贡献”。
12．—Oh，it's you！I didn't ________ you.—I've just had my hair cut，and I'm wearing new glasses.A．recognize B．realizeC．know D．organize答案与解析：A由两人对话可知彼此是认识的，故用recognize，本题用一般过去式表示在说话之前没有认出来。
13．This habit is hard to form________，but in the long run，it will do you good.A．in future B．at presentC．in present D．in the future答案与解析：B句意：这种习惯目前很难养成，但是从长远来看，它对你有好处。
at present 目前，与下文的in the long run 相对应。
14．The professor can hardly find sufficient grounds ________ his argument in favor of the theory.A．which to base on B．on which to baseC．to base on which D．which to be based答案与解析：B考查“介词＋which＋to do”结构。
句意：教授几乎不能找到足够的理由支持他的理论。
base...on 意为“基于，作为……的基础”。
15．He commanded that all the gates ________ to search for the spy.A．should shut B．would be shutC．shut D．be shut答案与解析：D考查command后跟虚拟语气。
command后跟that从句，从句要用虚拟语气，即should＋动词原形，其中should可以省略。
Ⅱ.阅读理解An 11-month-old baby helped raise the alarm that her mother had fallen down unconscious by using a mobile phone.Amelia Boyle，known as Millie，picked up the ringing mobile and answered the call when her mother Elizabeth,20，fainted in the hall of their home.Linda Wright，Millie's grandmother，was on the other end of the line and heard the baby say “Who's that？”and “Mama”．The girl is not allowed to play with the mobile so Mrs.Wright knew something was wrong with Millie's mother，who has a history of fainting and fitting，and dialed 999.Miss Boyle，whose phone it was，woke up in her home in Braintree，Essex，to find police and ambulance crews at her door.She became confused and told them she had not called them.A few minutes later three paramedics arrived and examined her.She did not need hospital treatment.Miss Boyle said，“I went upstairs to get Millie some clothes.I came downstairs again and I was going to get her dressed up as normal.”“She was moving around playing with some toys when I suddenly fainted between the passage and the living room blocking the stairs.”“My mum phoned me back on the home phone and when she didn't get through，she tried on the mobile，then the home phone again.”She added，“I am so lucky to have Millie.”“Millie does not seem to be disturbed by it.She must have watched me open the phone—sheis not usually allowed to play with it because she tends to stick it in her mouth.”“She is a very clever little girl.I was proud of her anyway but now she is even more special.”Mrs.Wright said，“If Millie hadn't answered the phone，I wouldn't have known what had happened.”1．Miss Boyle fell down ill while her baby was________.A．answering Mrs.Wright's phone callB．following her mother up and downC．having fun with her toysD．playing with her mother's mobile phone答案与解析：C细节理解题。