重庆八中2018-2019学年度(下)初三年级月考(word版 无听力部分 含答案)
重庆八中2019级初三第一次月考
重庆八中2018—2019学年度(上)初三年级第一次月考英语试题(本卷共九大题,满分150分,考试时间120分钟)第I卷(共100分)I. 听力测试。
(共30分)第一节(每小题1.5分,共9分)听一遍。
根据你所听到的句子,从A、B、C三个选项中选出最恰当的答语,并把答题卡上对应题目的答案标号涂黑。
1. A. It’s 8:00. B. It’s Sunday. C. It’s May 1st.2. A. It doesn’t matter. B. All right. C. I’m sorry, too.3. A. Sure. B. Thank you. C.That’s all right.4. A. You’re right. B. The same to you. C.Have a good time.5. A. Yes, I do. B. Yes, I have. C. Yes, I did.6. A. Don’t say that. B. Thank you. C. Yes, it is.第二节(每小题1.5分,共9分)听一遍。
根据你所听到的对话和问题,从A、B、C三个选项中选出正确答案,并把答题卡上对应题目的答案标号涂黑。
7. A. In the classroom. B. In a shop. C. In the library.8. A. A scarf. B. Nothing. C. A CD player.9. A. Cloudy. B. Rainy. C. Sunny.10. A. 4:30. B. At 5:30. C. At 5:00.11. A. By bike. B. On foot. C. By bus.12. A. Rosa. B. The boy. C. Rosa’s parents.第三节(每小题1.5分,共6分)听两遍。
根据你所听到的长对话,从A、B、C三个选项中选出正确答案,并把答题卡上对应题目的答案标号涂黑。
重庆八中 2018-2019学年 九年级上 半期测试卷
1 重庆市第八中学初2019级2018-2019学年(上)半期测试一、选择题(本大题12个小题,每小题4分,共48分) 1. 单项式2a 的系数是( )A.3B.2C.1D.0 2. 在下列四个图形中,属于轴对称图形的是( )3. 下列计算,结果等于a 3的是( )A.a+a 2B.a 4-aC.2a ·aD.a 5÷a 2 4. 下列说法正确的是( )A.一组数据的方差越小,则这组数据的波动也越小B.了解我国中学生的课外阅读情况适宜采用全面调查C.了解一批电视机的使用寿命适宜采用全面调查D.旅客上飞机前的安检适宜采用抽样调查 5. 下列几何体中,主视图为三角形的是( )6. 使x -2有意义的x 的取值范围是( )A.x ≥2B.x>2C.x ≤ 2D.x<2 7. 下列命题错误的是( )A.平行四边形有两条对称轴B.对顶角相等C.角平分线上的点到角两边的距离相等D.菱形的对角线互相垂直平分 8.如图,CD 为圆O 的直径,弦AB ⊥CD ,垂足为E ,CE=1,半径为25,则弦AB 的长为( )A.24B.14C.10D.7 9.如图,在平行四边形ABCD 中,E 是DC 上的点,DE:EC=2:1,连接AE 交BD 于点F,则△DEF 与△BAF 的面积之比为( )A.3:2B.2:3C.9:4D.4:9第8图 第9图10. 某班的同学想测量一教楼AB 的高度.如图,大楼前有一段斜坡BC,已知BC 的长为16米,2 它的坡度i=1:3.在离C 点45米的D 处,测得一教楼顶端A 的仰角为37°,则一教楼AB 的高度约为( )米(结果精确到0.1米)(参考数据:sin37°≈0.60,cos37°≈0.80,tan37°≈0.75,3≈1.73)A.44.1B.39.8C.36.1D.25.911. 如图,抛物线y=ax 2+bx+c(a ≠0)与x 轴交于A(-1,0),B(3,0)两点,与y 轴 交于点C,顶点为D.下列结论正确的是( ) A.abc<0 B.3a+c=0C.4a-2b+c<0D.方程ax 2+bx+c=-2(a ≠0)有两个不相等的实数根 12. 如图,反比例函数y=xk(k>0)的图象与矩形AOBC 的边AC 、BC 分别相交于点E 、F,点C 的坐标为(8,6).将△CEF 沿EF 翻折,C 点好落在OB 上的点D 处,则k 的值为( ) A.421 B.6 C.12 D.221二、填空题:(每小题4分,共24分) 13. 计算:|-3|-(-2)0=_______.14. 若正多边形的一个外角是72°,则该正多边形的边数为_______.15. 小李老师为了了解学生的数学周考成绩,在班级随机抽查了10名学生的成绩,其统计数据如下表:3则这10名学生的数学周考成绩的中位数是_______分.16.把两块同样大小的含45°角的三角尺按如图所示的方式放置,其中一块三角尺的锐角顶点与另一块的直角顶点重合于点A,且另三个锐角顶点B,C,D 在同一直线上,若AB=23,则CD=_______.17.一辆快车从甲地出发到乙地,一辆慢车从乙地出发到甲地,两车同时出发,匀速行驶,慢车到甲地后停止行驶,快车到乙地后休息半小时,然后以另一速度返回甲地两车之间的距离y(千米)与快车行驶的时间x(小时)之间的函数关系如图所示,当慢车到达甲地时,快车与乙地的距离为_______千米18. 一间手工作坊,分成了两块区域,第一块区域里摆了一张四方桌(四条腿)和若干圆凳(三 脚凳),第二块区域里摆了一张圆形桌(六条腿)和若干方凳(四脚凳)。
重庆八中2018-2019学年度(下)初三年级月考(word版 无听力部分 含答案)
重庆市八中2018-2019 学年度(下)初三年级月考I听力测试。
II单项选择。
21.--I hurt my leg by accident. Should I take X-ray? –Of course, you should. The doctor will usually check _X-ray you take first.A.an, \B.a, aC.an, theD.a, the22.--You’re playing the violin so beautifully! –Thank you! I practice it very hard every day so that I can bea one day.A.pianistB.dentistC.scientistD.musician23. —Uncle Lee, did you see my father? –Yes, I happened him at Yonghui supermarket half an hour ago.A.meetB.meetingC.metD.to meet24. My teacher Amy is a beautiful lady and looks much than her age because she does exercise a lot.A.niceB.energeticC.youngerD.older25. —What do you think of the science fiction movie ”The wondering Earth” made in China? –I found a great success for Chinese to make such a wonderful film like that.A.itB.it’sC.thatD.that’s26. visitors come to Chongqing to take cable cars(缆车)during the vacation because Chongqing has become a popular destination on the Internet(网红城市)now.A.ThousandB.ThousandsC.Thousand ofD.Thousands of27. —Haven’t you seen the sign” No Smoking In The Ronn” here? –Sorry, when I came in. I’ll put out the cigarette right away.A.I didn’t see it.B.I haven’t seen it.C.I will see it.D.I was seeing it.28. Remember not to go across the street the traffic light turns green.A.becauseB.afterC.whenD.until29.One of my family rules is that I can’t watch TV unless my homework.A.was finishedB.is finishedC.will be finishedD.finishes30. —I’m so excited about Huawei’s new fold able(可折叠的)smartphone. Do you know?–Very soon. We’ll see.A.how can I get oneB.how I can get oneC.when will it come outD.when it will come outIII.完型填空。
重庆市第八中学校2018届九年级下学期第一次全真模拟英语试题(无答案)
重庆八中 2017~2018 学年度(下)初三年级第一次全真模拟考试英语试题第 I 卷(共 95 分)I.听力测试。
(共 30 分)第一节(每小题 1.5 分,共 9 分)听一遍。
根据你所听到的句子,从 A、B、C 三个选项中选出最恰当的答语,并把答题卡上对应题目的答案标号涂黑。
1. A. Nice to meet you, too. B. Many thanks. C. The same to you.2. A. Yes, please. B. I like it. C. Tea, please.3. A. Never mind. B. Good luck! C. No problem.4. A. Hold on, please. B. Yes. Who are you? C. Why not?5. A. It doesn’t matter. B. You are welcome. C. I’m sorry.6. A. Yes, I can. B. Good idea. C. No, it isn’t.第二节(每小题 1.5 分,共 9 分)听一遍。
根据你所听到的对话和问题,从 A、B、C 三个选项中选出正确答案,并把答题卡上对应题目的答案标号涂黑。
7. A. Go shopping. B. Go bike-riding. C. Go swimming.8. A. To the supermarket. B. To the restaurant. C. To the bank.9. A. Jane. B. Jane’s father. C. Jane’s friend.10. A. Apples. B. Milk. C. Mild shake.11. A. A day. B. Six days. C. Seven days.12. A. Sunny. B. Rainy. C. Snowy.第三节(每小题 1.5 分,共 6 分)听两遍。
重庆八中初2018级初三(上)第一次月考英语(无听力无答案)
重庆⼋中初2018级初三(上)第⼀次⽉考英语(⽆听⼒⽆答案)重庆⼋中初2018级初三(上)第⼀次⽉考英语试题第I 卷I 听⼒测试。
II 单项选择。
(每⼩题1分,共15分)从A、B、C、D四个选项中选出可以填⼊空⽩处的最佳答案,并把答题卡上对应题⽬的答案涂⿊。
21.---There’s _______ useful word in this sentence. Do you know its meaning?---Sorry, I don’t. But I can _______ in the dictionary soon.A.a, look up itB. an, look up itC. an, look it upD. a, look it up22.---Excuse me, is there a _______ near here? I want to buy some books.---Sure, go along Center Street and turn left, then you can find it.A.libraryB. restroomC. restaurantD. bookstore23.If you want to learn a language _______, you should pay more attention to _______ it.A.good, useB. well, usingC. good, usingD. well, use24.It’s no nice _______ you to help me with my _______ Englis h.A.of, spokenB. for, speakingC. of, speakingD. for, spoken25.You’ll remember _______ you have learned _______ it’s a little difficult for you.A.what, becauseB. that, thoughC. what, althoughD. that, if26.---_______ nice weather it is today! Why not _______ out for a walk?---That sounds good.A.What a, goB. What, goC. How a, to goD. How, going27.---One of the drivers _______ in this car accident already.---Sorry to hear that.A.has diedB. have deadC. has been diedD. have been dead28.Because he ate _______ junk food, he _______ three pounds last month.A.too much, put onB. much too, put upC. too many, put offD. many too, put down29.---Look! There’s an old man _______ on the ground.---Let’s go and see what _______./doc/152f0bb577eeaeaad1f34693daef5ef7bb0d1268.html y, happenedB. lying, happenedC. lied, has happenedD. lying, was happened30.---He warned us _______ in the deep river.---Yes. I hear that whoever swims in it will end up _______ his life.A.don’t swim, losingB. not swim, lostC. not to swim, losingD. not to swim, to lose31.---Have you read the novel _______ A Christmas Carol?---Yes, I _______ it a month ago./doc/152f0bb577eeaeaad1f34693daef5ef7bb0d1268.html d, have readB. called, readC. is named, have readD. is calling, read32.---I wonder _______ the man is a businessman?---That’s for sure. He often goes _______ business across the country.A.that, forB. if, onC. whether, toD. that, in33.Asking for help _______ this way sounds more _______.A.by, politelyB. at, politeC. on, politelyD. in, polite34.---Excuse me, could you please tell me _______?---Sure, go along Center Street and turn left, the bank is across from the supermarket.A.how can I get to the bankB. how to get the bankC. which is way to the bankD. where is the bank35.---How about dressing up as ghosts on Halloween?---_______. What should we do to prepare for it?A.Have a good timeB. I don’t think soC. That sounds like funD. That’s too scaryIII 完型填空。
重庆八中初2018级初三下期英语定时训练(三)无听力部分无答案
重庆八中初2018级初三(下)定时训练(三)英语试题第I卷(共95分)I.听力测试(共30分)略II.单项选择(每小题1分,共15分)21.Look! There’s 11-year-old boy students under the tree.A. aB. theC. anD. /22. The two sessions(两会)were held in March in Beijing. If you want to get further about it, you can search the Internet.A. informationB. newsC. messageD. words23. students enjoyed themselves yesterday in Happy Valley, Lijia, Chongqing.A. Two thousandsB. Two thousands ofC. Thousand ofD. Two thousand24.-Who taught the pop song?-Nobody. We learned it by .A. your, usB. yours, usC. you, ourselvesD. you, ourselves25. David is badly hurt, so he can move his legs now.A. hardB. hardlyC. difficultD. nearly26. You should pay attention to the traffic lights when you go the streets.A. pastB. throughC. overD. across27. It’s said that a new bridge in three months over the jialing River.A. was builtB. will buildC. would be buildD. will be built28.-Does the CD belong to Mary?-No, it be hers. Look, there’s name “Mike” on it.A.mustn’tB. mayC. can’tD. need29. The kites by hand are very popular with the foreigners. They sell very well.A.are madeB. to makeC. madeD. making30. After the people the fire, all of them felt tired out.A. put outB. put offC. put awayD. put on31. time you spend with other people, friends you’ll have.A. The more; the lessB. The less; the fewerC. The fewer; the moreD. The less; the less32.-When will the meeting begin?-It start until everybody .A. will; will arriveB. won’t; arrivesC. will; arrivesD. won’t; will arrive33.Study hard, you’ll achieve success in your exam.A. orB. butC. andD. neither34.There many trees in this forest, but now most of them have disappeared.A.are used to beB. used to haveed to beD. is used to35.We all wondered .A. that Tony got to school on time this morning.B. what’s the matter with Tony.C.whether Tony often walked to schoolD.whom was Tony talking withIII. 完型填空。
重庆八中2018-2019学年度(下)初三年级第一次全真模拟考试数学试题答案
重庆八中2018—2019学年度(下)初三年级第一次全真模拟考试数 学 试 题(参考答案)一、选择题DC ACABD BBBBB :1211:106:51---;;二、填空题13:6105.3⨯ 14:π41 15:6 16:12 17:90 18:5750 三、解答题19.(1)解:原式222244=a ab b a b -++- …………………3分2=54a ab - …………………5分(2)解:原式2(2)1=1(2)(2)a a a a a +-⨯--+ …………………3分 22a a +=- …………………5分 20.(1)设B ∠为xAC BC B A x=∠=∠=∵∴ 又44ACB B x ∠=∠=∵在ABC ∆中,180A B ACB ∠+∠+∠=︒4180x x x ∴++=︒,解得=30x ︒∵点D 是AC 边中点且DE AC ⊥AE CE ∴=(三线合一)30,90ECD BCE ∴∠=︒∠=︒…………………5分 (2)设CE 为a在t R EBC ∆中,=30B ∠︒2B E a ∴=由(1)可得,AE EC a ==33AB a AB EC∴=∴=…………………10分 21.(1)4,8,85.5,88a b c d ====…………………4分(2)600人 解:651000+1200=6002020⨯⨯…………………6分 (3)初二 …………………8分理由:①初二的平均数更大,说明学生普遍水平更高②初二的方差更小,说明学生之间水平差异更小③初二中位数更大,中等水平学生水平更高…………………10分22.(1)解:设每千克售价降低x 元100+20=280x …………………2分=9x答:每千克的售价应为21元. …………………4分(2)解:设桃片售价为y 元[](2115)280320(15)1002030)y y -⨯+=-⨯+-()…………………7分2(25)0y -=25y =答:桃片售价应为25元/千克. …………………10分23.(1)2112y x x =+-…………………2分 (2)图象见右…………………6分 (3)①213y y y <<…………………8分②1311,8242k x x <≤≤≤≠且 24.(1)中21a n =+,222b n n =+,2221c n n =++(n 为正整数) ∵()()()2222222222212214421c b n n n n n n n a -=++-+=++=+=, ∴222a b c +=,∴21a n =+,222b n n =+,2221c n n =++(n 为正整数)是一组勾股数. ………………………………………………………………4分(2):5n = 221(5)2a m ∴=-,5b m =,21(25)2c m =+直角三角形的一边长为37 ∴分三种情况讨论,①当37a =时,221(5)372m -= 解得m =±5分 ②当37b =时,537m =, 解得375m =(不合题意舍去);………6分 ③当37c =时,2137(25)2m =+ 解得7m =±,………8分 m n 、为正整数7m ∴=,把7m =代入得,12a =,35b =.综上所述:当5n =时,一边长为37的直角三角形另两边的长分别为12,35.……10分25.(1)解:设BE 为xtan 33316ABE AE BE AE xBC BD DE BE x∠=====+=+∵∴∴∵在AED ∆中,222(3)16(16)x x +=+4x =或0(舍去)20BC ∴=,AB =ABCD C ∴=平行四边形分(2)方法一:连接DF ,过C 作CM DB ⊥四边形ABCD 为平行四边形//,AD BC AO OC ∴=45ADB DBC ∴∠=∠=︒又90AED ∠=︒ AED ∴∆是等腰直角三角形 AE DE ∴=在AOE ∆和MOC 中,(),2AOE MOC AEO OMC OA OC AOE MOC AAS OM OE CM DEME OE AF ∠=∠⎧⎪∠=∠⎨⎪=⎩∴≅∴==∴== A E A F D E M E ∴-=-,即EF DM =在DEF 和DCM 中,(),EF DM FED DMCDE CM DFE DMC SAS DF DC FDE DCM=⎧⎪∠=∠⎨⎪=⎩∴≅∴=∠=∠又+=90MDC DCM ∠∠︒ 90FDE EDF ∴∠+∠=︒且DF DC =DFC ∴为等腰直角三角形CF ∴…………………10分方法二:过C 作CM //OE 交AE 的延长线于M ,连接DM .(下略)四、解答题26. (1)设294P m m ⎛-- ⎝5,4Q m m ⎛- ⎝∴()29222PQMN C QP NP m ⎛=+=+ ⎝矩形∵0<,开口向下,∴m =当 (,3P - ∵最少时间12t RK KT TB =++, ∵R -,作R 关于y 轴对称'R ⎛- ⎝过'R 点作直线:4l y =- 的垂线交于H 点'H R 即为所求. ''''t R K K T TH =++ ∴过''R 作''R H l ⊥ ∴min 9'2t R H =(2)综上()()((21310,6;0,12;0,3;0,3E E E E +-。
初中英语 重庆市第八中学九年级上学期第一次月考试题(解析版 )
重庆八中初2019级初三(上)第一次月考英语试题第I卷(共95分)I.听力测试(共30分)略II.单项选择(每小题1分,共15分)从A、B、C、D四个选项中选出可以填入空白处的最佳答案’并把答题卡上对应题目涂黑。
A.a; theB.an; theC.a; /D.an;/【答案】B【难度】容易【解析】形容词exciting为元音音标发音开头的单词,需用不定冠词an; 第二空特指上文提到的这部电影,需用定冠词“the”。
【易错点】D。
第二空学生易忽视特指。
A.if; whetherB. whether; whetherC.if; ifD.whether; that【答案】C【难度】容易【解析】第一句为宾语从句,可用if/whether,表“是否”。
第二句考查条件状语从句,只能用if引导,因此选C。
【易错点】D.学生误将第二句判断为宾从,实则为条件状从。
yourself?A.ask; writeB. to ask; writeC.ask; writingD.asking; write【答案】C【难度】容易【解析】考查句型和固定搭配。
Why not后跟动词原型;finish doing sth.【易错点】B。
学生容易记错搭配,Why not后面不是跟to do sth, 而是动词原形。
A.louderB. more loudlyC.more aloudD.more loud【答案】A【难度】中等【解析】考查loud/aloud/loudly区别:aloud adv.大声地;loudly adv. 吵闹地;loud adj.&adv. 可与aloud和loudly互唤。
大声朗读可用:read aloud和read in a loud voice表示,此题考查了loud的比较级:louder。
综合以上,选A【易错点】D。
记错loud的比较级。
A. the otherB. the othersC. anotherD. other【答案】C【难度】中等【解析】the other代表两者中的另一个,the others代表其他(剩下)的,another代表另一个,后常跟单数名词,other代表其他的,后常跟复数名词。
重庆初三初中英语月考试卷带答案解析
重庆初三初中英语月考试卷班级:___________ 姓名:___________ 分数:___________一、单项选择1.Is Handan ______ modern city or ______ ancient one?A.a; an B.an; a C.a; a D.an; an2. I have never seen _______________ before. What about you?A.so a film B.so a nice film C.such a nice film D.such nice a film 3.—Is ________ here?—No, Peter and Tony have asked for leave.A.anybody B.somebody C.everybody D.nobody4.Tom is one of the ____________ students in our class.A.tall B.taller C.more taller D.tallest5. ___________ have you ___________ the meat?A.How; do with B.What; do with C.How; done with D.What; done with 6.The old building still looks beautiful. It is about _______________.A.twelve-metre-high B.twelve-metre highC.twelve-metres-high D.twelve metres high7.Mr. Stevenson is great to work for—I really couldn't ask for a ________ boss.A.better B.good C.best D.still better8.We feel our duty to make our country a better place.A.it B.this C.that D.one9.There are few new words in this article, __________ no one can understand it.A.and B.or C.but D.so10.—Do you mind if I turn on the TV?—______________. My father is sleeping.A.Better not B.Not at all C.No, I don’t mind D.That’s all right 11.—Would you like some tea or coffee?— .A.Yes, tea B.No, coffee C.Thanks a lot D.Tea, please 12.The new station being built for the next Asian Games will be ________ the present one.A.as three times big as B.three times as big asC.as big as three times D.as big three times as13. The more you smile, the ________ you will feel.A.happy B.happier C.happily D.more happily14.As it reported, it is 100 years _____________ Tsinghua University was founded.A.when B.before C.after D.since15. I ________ my hometown for a long time. I really miss it!A.left B.went away from C.have left D.have been away from 16.— __________ will the meeting start?—In about ten minutes, I think.A.How long B.How soon C.How often D.How far17. The Spring Festival __________ in January or February.A.celebrates B.is celebrated C.celebrated D.was celebrated18. Johnny ran very fast _________he could catch the early bus.A.so that B.as soon as C.some day D.of course19.Do you know the man who _________on the road just now?A.lied B.lay C.lying D.laid20. Jenny is on holiday now. I wonder ______________________.A.when she will come back B.when she came backC.when will she come back D.when did she come back二、阅读理解1.One day a poor man was traveling on horseback. At noon, he tied his horse to a tree and then to eat something. A few minutes later, a rich man came along and tied his horse to the same tree.“Please tie your horse to another tree,” said the poor man. “My horse is wild. It will kill yours.” the rich man said, “I shall tie my horse as I like!” he tied up his horse and had his lunch nearby. After a moment they heard aterrible , the two horses were fighting. They went up to them, but it was too . The ri ch man’s horse was killed. “See what your horse has done!” cried the rich man. “You will have to it.” And he brought the poor man before Mr. Know.Mr. Know asked the poor man some questions. But he made no. At last Mr. Know said, “This man is dumb. He cann ot speak.”“Oh,” the rich man shouted. “He can! He spoke to me when I met him.”“Are you sure?” asked Mr. Know. “What did he?”“He told me not to tie my horse to the same tree because his horse was wild and would kill my horse.”“Oh,” said Mr. Know. “So he you. Then can you expect to get money him?”The rich man said nothing and left silently.【1】A.put down B.set down C.sat down D.turned down【2】A.So B.But C.And D.Though【3】A.song B.word C.bell D.noise【4】A.late B.slow C.hard D.quick【5】A.pay for B.look for C.wait for D.care for【6】A.idea B.mistake C.money D.answer【7】A.quietly B.angrily C.happily D.heavily【8】A.speak B.tell C.talk D.say【9】A.helped B.thanked C.warned D.ordered【10】A.for B.from C.with D.about2.Reporter: How long have you been a firefighter?Wilson: For eight years.Reporter: How did you get started?Wilson: First, I had to take a lot of tests in two weeks. Then, I went to the firefighter school for four months. 1 learned how to put out fires and how to use equipment. I also had a full-time training every day!Reporter: How do you stay safe on the job?Wilson: I wear special clothing. It helps keep me protected from fire. I also carry an oxygen tank (氧气瓶) and a mask (面具). They help me to breathe in a smoke-filled building.Reporter: Are there any new tools that firefighters use?Wilson: We have a special camera that can see in the dark. It can find heat. That way, we can exactly tell the place of a fire.Reporter: Do you save pets?Wilson: Just three days ago, I helped save some cats. They were hiding under the beds. Pets usually hide duringa fire because they are afraid of danger.Reporter: Do you ever get afraid?Wilson: No. There is no time to be afraid. I just think about what to do to put out the fire safely. Reporter: What do you like best about being a firefighter?Wilson: Helping people!【1】Kate Wilson has done her job for____________.A.2 weeks B.3 days C.4 months D.8 years【2】 To become a firefighter, Kate Wilson ____________at first.A.took a lot of tests B.learned to stay safeC.saved some animals D.used fire equipment【3】58. Kate Wilson says she does not get afraid because_____________.A.she has an oxygen tankB.she knows how to fight firesC.she enjoys finding heatD.she is too busy putting out fires【4】59. As a firefighter, Kate Wilson likes____________ most.A.wearing a mask B.asking questionsC.helping people D.hiding in smoke【5】60. What did the reporter make this interview for?A.To tell people what a firefighter does.B.To teach people how to prevent fires.C.To make people want to be firefighters.D.To show people how a firefighter is trained.boratory work is your chance to learn science firsthand. It can be fun but you must be careful to prevent injury. Listen closely when your teacher reads and explains the rules before your first lab lesson.A.before B.since C.during D.after【2】Before every experiment, you should ___________.A.taste the chemicals firstB.clean all the apparatusC.read all instructions carefullyD.report all the accidents to the teacher【3】When you are not sure how to use all apparatus, ___________.A.try them on your own B.read the rules carefullyC.ask your teacher for help D.put them back【4】 It is clear that you can ___________.A.bring food into the lab B.enter the lab at any timeC.smell chemicals as you like D.learn science directly in the lab【5】 If you get chemicals on the clothing, you can find ways to solve it in the part ___________.A.Before the Experiment B.First AidC.During the Experiment D.After the Experiment4.I am a professor of sports and exercise so I often deal with nervousness in my research with sports people. Actually, most people experience nervousness at some time or another.If you are feeling anxious, my advice is to first find the cause or causes. Make a list of those things that are making you nervous and work out which ones you can do something about. Focus all of your efforts on managing the causes that you can control.Most people cannot tell the difference between controllable(可控制的) and uncontrollable causes, so things they can’t control become a big reason for ner vousness. Dealing with this is very important if people want to keep a healthy mind.Simply try to accept the uncontrollable causes of nervousness. You might be worried about the weather on a big day, an accident or an attack on the train, or perhaps just things that other people are doing at work. The results may be very important but there is still no use worrying because you can’t control any of these things. Accept that you can’t control everything. Once you understand this, it becomes easier not to wor ry.If a situation, such as swimming, is causing you to be anxious, try to face it as often as possible so that you can get used to it.It can often help to think about yourself doing the thing that makes you nervous—then close your eyes and imagine it going well. Imagine how the flight or job interview is going to happen so that you can get used to it. This will help you understand that the thing you fear most is probably not going to happen.【1】Who wrote this passage?A.A reporter.B.A sportsman.C.A patient.D.A professor.【2】The writer thinks there is no use worrying about some causes of nervousness because_____________. A.most are not very importantB.they are not the real causes of the problemC.they cannot be controlled by peopleD.it’s better to deal with one cause at a time【3】 If swimming makes you nervous, what should you do according to the writer?A.Go swimming often to get used to it.B.Avoid going to the swimming pool.C.Find a swimming teacher.D.Imagine watching others swim.【4】What is true about nervousness according to the passage?A.It usually has only one cause.B.It is usually caused by people.C.People can easily manage it.D.Most people suffer from it.【5】What is the main purpose of this passage?A.To introduce the writer’s sports experience.B.To advise on how to deal with nervousness.C.To help people remember their fears.D.To explain the dangers of nervousness.5.Have you ever complained(抱怨)why life is so tiring? Does the sky sometimes seem dark to you? Are your studies sometimes not successful? Well, friends, cheer up and smile all the time. If you see the world with your warm heart, you’ll find that the whole wor ld smiles to you.While in school, sometimes you are tired of your lessons, but have you ever noticed the happy smile on your teacher’s face when you did a good job?One day it is fine. But just before you want to go out, it suddenly starts to rain. Maybe you would feel very sad and start complaining about the weather. But dear friends, why don’t you sit down and listen to the free concert that the nature offers you? And with the rain in time, crops in the fields will grow better and better and farmers will have a good harvest.Although everyone wants to succeed in what he tries to do, sometimes he has to face failure bravely. I think failure is not terrible, and the terrible thing is that we are afraid of it and give up hope. When we face failure, we must be confident in ourselves, draw a useful lesson from it and try our best to finish what we have decided to do. As a popular saying goes, “Failure is the mother of success.”Attitude(态度)decides everything. With an optimistic(乐观)attitude life is easy and pleasant. Let’s smile to whatever we meet and the whole world will smile to us.【1】判断正误(“T”表示正确,“F”表示错误)You will always succeed if you see the world with a warm heart.【2】A student can make his teacher happy by ---------------------___________________________.【3】What can we do if we are stopped by a sudden rain according to the passage?___________________________________________________________________________【4】What is more terrible than failure according to the passage?___________________________________________________________________________【5】Put the underlined sentence in the passage into Chinese.___________________________________________________________________________三、补充句子根据句意及所给提示,补全单词或用单词、固定短语、固定搭配的正确形式填空。
最新-重庆八中2018学年初三年级第一学月考试 精品
重庆八中2018—2018学年初三年级第一学月考试物理试题(满分100分,完卷时间90分钟)一、选择题(以下各题只有一个正确选项,每小题3分,共45分)1、直升飞机在空中匀速下降的过程中,以下说法正确的是()A、直升飞机的动能不变,机械能也不变B、直升飞机的重力势能减小,机械能也减小C、直升飞机的动能转化为重力势能D、直升飞机的重力势能转化为动能2、下列各组物体中,全部是导体的是()A、碳棒、铜丝、陶瓷B、食盐水、铜丝、水银C、铜丝、大地、橡胶D、海水、玻璃、油3、下列事例中,不属于利用做功改变物体内能的是()A、冬天手冷,两手互相搓搓就暖和B、钻木取火C、冬天用热手袋取暖D、从滑梯上滑下时,臀部有灼热的感觉4、下列事例中,不属于势能转化为动能的是()A、弹簧枪将子弹射出去的过程B、推开弹簧门的过程C、木块加速下落的过程D、人造地球卫星从远地点向近地点运动的过程5、以下对分子动理论的理解中正确的是()A、由于压缩液体十分困难,这说明液体分子间没有空隙B、固体很难被拉伸,说明固体分子间只存在引力C、分子间距离增大时,引力增大,斥力减小,最后引力起主要作用D、扩散现象能证明分子间有空隙6、下列物体中一定带负电的是()A、与丝绸摩擦过的玻璃棒B、能与带正电物体相吸引的轻小物体C、与带正电的物体接触的验电器D、与毛皮摩擦过的橡胶棒7、如图1所示,A、B是正在通电的一段金属导体,实心点代表电子,箭头方向为它的运动方向,则下列说法中错误的是()A、导体中的电流方向是从A到BB、导体中的电流方向是从B到AC、导体的A端接的是电源的负极D、导体的电流等效于正电荷从B向A移动的电流8、下列说法中正确的是()A、电路中电池供电时是将电能转化为化学能B、电路中用电器工作时是将其他能转化为电能C、电源出现短路时,将烧坏用电器D、电路中要有持续电流,电路必须是闭合的9、关于温度、热量和内能,下列说法中正确的是()A、物体吸收热量,温度一定升高B、物体温度降低,一定是因为放出了热量C、1 kg 0℃的水的内能比1 kg 0℃的冰块的内能大D、物体内能增加,温度一定升高10、质量相同的甲、乙两个金属块,已知甲的比热容小于乙的比热容,如让它们吸收相等的热量后再相接触,下列说法正确的是()A、温度将由甲传给乙B、热量将由甲传给乙C、热量将由乙传给甲D、它们之间可能不发生热传递11、水是生活中最重要的一种物质,它有许多重要的性质。
重庆初三初中英语月考试卷带答案解析
重庆初三初中英语月考试卷班级:___________ 姓名:___________ 分数:___________一、单项选择1.--Did you enjoy your stay in Beijing , Mrs Black?--Yes, I had __________wonderful time.A.a B.an C.the D./2.--Who teaches you Japanese?--I teach _________.A.me B.my C.myself D.mine3.We all find _________ important to do what the teachers tell us.A.that B.this C.it D.them4.--______is waiting for you . He wants to say hi to you.--Oh! That’s Roy again ! He does it__________.A.Somebody; everyday B.Somebody; every dayC.Anybody; everyday D.Anybody; every day5.--You bought the car about ten years ago?-- Yes ._____it’s old , it still runs well.A. SinceB. BecauseC. Although6.--Shall we go for a ride tomorrow?--Well, it all ______ the weather.A.belongs to B.happens toC.depends on D.concentrates on7.The doctor asked me _______ more fruit and vegetables to keep healthy.A.to eat B.eating C.ate D.eat8.--The meat is _________ delicious. --Yes, but don’t eat _________.A.too much; too much B.much too; too muchC.too much; much too D.much too; much too9.I’ve_____five pounds. I think I need to lose weight.A.put on B.take off C.put away D.take away 10.Don’t__________your dream. I’m sure your dream will come true one day.A.take off B.come up C.take up D.give up 11.The mountain was ________ high _________few people in our city reached the top.A.so;as B.so;that C.as;as D.too;to 12.Jack’s mother wondered_________.A.how much he cost the computerB.how much he paid for the computerC.how much the computer will cost himD.how much did he spend on the computer13.--Would you please tell me________this DV?--Yes.It’s very easy.A.where to use B.how to useC.when to use D.what to use14.Ask your brother to call me if he ______ back tomorrow.A.will come B.is come C.coming D.Comes15.---Do you think people can live on the moon one day?---May be. However, it may take ________ years to make it.A.thousand of B.thousandC.thousands of D.two thousand of16.Don’t ________ your exams. They are very easy.A.worry B.worried about C.worry about D.be worried17.---Are you _______ in sports?---No, I like ________ computer games.A.interested , interesting B.interested, interestedC.interesting, interested D.interesting, interesting18.This kind of soup ________ delicious. I like it a lot.A.sounds B.feels C.tastes D.Looks19.I must stay here _________ better.A.until she feels B.until she will feelC.when she feels D.after she will feel20.Our teacher told me ______ football in the street.A.don’t play B.not playC.not to play D. to not play二、完形填空完型填空(每小题1.5分,共15分)Have you ever had a day when everything goes wrong?Not too long ago, I was having one of those days. In low spirits, I was unhappy and ______. I was thinking about my problems. After all, no one else was ______the same problems as Iwas.I expressed my sad_________to my mother, hoping for some pity. Instead, she said, “I heard Lily was having a difficult day,_______.Why don’t you make her some cookies and we’ll take them to her this afternoon?”I didn’t really want to, but decided that I didn’t want to go bac k to my own problems just yet. I made the______and placed them on a plate. Then I made a card with a sunflower on it and wrote a small warm and sweet note.______, we dropped in at my friend’s house. I went to the door and rang the bell. Soon , Lily came t o the door.She didn’t expect our visit. So she looked at us in surprise. Before she could say________, I rushed, “I heard that you were having a hard day and decided to bring you something. I hope your day goes_______.”The look on Lily’s face was getting bright in that small act, It was as if a dark sky suddenly shone with the golden rays of the sun. Her day was__________.I got back into the car and for some reason, I felt a lot better myself. That day I experienced the truth“Those who bring ________to th e lives of others cannot keep it from themselves.”【1】A.excited B.angry C.pleased D.sad【2】A.experiencing B.expecting C.exercising D.explaining【3】A.plan B.idea C.state D.result【4】A.also B.too C.either D.neither【5】A.hamburgers B.cookies C.cakes D.bread【6】A.That morning B.That evening C.That afternoon D.That night【7】A.anything B.something C.nothing D.everything【8】A.bad B.well C.worse D.better【9】A.cheered up B.waken up C.turned up D.cleaned up【10】A.a cookie B.sunshine C.a present D.help三、阅读理解1.A hare was very popular with the other animals who all said they were her friends. But one day she heard the hounds(猎犬) getting close and hoped to escape them with the help of her many friends. So, she went to the horse, and asked him to carry her away from the hounds on his back. But he refused, because he had important work to do for his master. He felt sure that all her other friends would come to help her.She then came to the bull, and hoped that he would repel the hounds with his horns(角).The bull rep lied,” I am very sorry, but I have an appointment with a lady; but I feel sure that our friend , the goat, will do what you want.” The goat, however, feared that his back might do her some harm if he took her upon it, The sheep, she felt sure,was the proper friend to ask for help.So she went to the sheep and told him the situation. The sheep replied, “Another time , my dear friend. I do not like to have anything to do with it , as hounds have been known for eating sheep as well as hares.”The hare then went, as a last hope, to the calf(小牛),who regretted that be was unable to help her , as did not like to take the responsibility(责任)upon himself. By this time the hounds were quite near, and the hare started to run and luckily escaped.【1】What do we know about the hare?A.She was strong enough to face all the dangers.B.She was friendly and all animals loved to help her.C.She was ready to help the other animals when necessary.D.She got along well with the other animals and had a lot of friends.【2】What happened to the hare one day?A.The horse carried her away on his back.B.Her enemy came near and she was in danger.C.She had an argument with her friend,the bull.D.The goat hurt her when taking her upon his back.【3】What does the underlined word “repel”mean in Chinese?A.击退B.厌恶C.排斥D.拒绝【4】What do you think of the sheep?A.Helpless.B.Brave.C.Friendly.D.Smart.【5】What does the story want to tell us?A.Don’t judge a book by its cover .B.One’s mind works fast in time of danger.C.Sometimes enemies can become good friends.D.Having too many friends means no friends sometimes.2.Betty and I are best friends . Our birthdays are on the same day, so every year we have a birthday party together. But this year ,we had a costume party instead.While we were writing the invitations, my mum came in and asked, “Why not invite John?”John had been in our class for only a few months , but he was always getting better grades in math than anyone else in class. I wrinkled(皱起)my nose and said, “Mum, he wears the same pants to school every day. How could he even afford a costume?”Mum said nothing . The next day, mum gave me an envelope with a shopping certificate(凭证)in it. “I thought it would be nice of you to give this to John ,”mum said. But how? We didn’t want to make John embarrassed. We discussed it for a long time . Finally, Betty and I had a good idea.On the day of our party, kids arrived, dressed differently. John arrived, in an old sheet(床单),but still in the same brown pants as usual. We danced , ate snacks and played games in groups. Before eating the birthday cake, Betty said in la loud voice, “Now it’s time for the great prize game, It’s the following riddle …”It was a math game. None of us was surprised when John came up with the right answer first and walked off with the envelope. Everything went on well as we planned. John wore a new pair of pants and a new shirt the next week. He felt happy . So did we.When we helped others , we need to find a proper way, or we may hurt them in another way.【1】The two girls and John were in the same_________.A.group B.family C.team D.class【2】John’s family may be very______according to the passage.A.far B.poor C.rich D.small【3】How did John get the prize during the party?A.By helping others.B.By asking for help.C.By getting good grades in study.D.By winning the math game.【4】John______with the shopping certificate after the party.A.watched a basketball matchB.saw a movieC.bought something to wearD.made a phone call【5】The two girls felt_________when they found John wearing his new clothes.A.happy B.sorry C.sad D.Angry3.Dubai is a city of big business, expensive hotels , skyscrapers(摩天楼),and shopping malls, In the early 20th century, Dubai was a successful trading port. People from the world stopped in Dubai to do business, But it was still a small city, and most people lived as fishermen and businessmen. Then in 1966, oil was discovered. This brought a lot of money into the area, and soon Dubai began to change.Today Dubai is one of the world’s most important business centers. In fact , each year the city gets its money mainly from business, not oil.Recently Dubai has attracted more and more visitors from abroad, They come to relax on its beaches, and every year, millions visit just to go shopping!Dubai is also one of the world’s fastest growing cities. Many tall buildin gs are built in months. The city also has many man-made islands.One of these, the Palm Jumeirah, is like a palm tree(棕榈树)and is very beautiful. The city is still an amazing mix(混合体)of people from different countries . The people from 150 countries live and work in Dubai , and foreigners now outnumber Dubai natives (本地人)by eight to one!Many people welcome the city’s growth. But an increasing number of Dubai natives worry about the speed of change As a Dubai native says, “We must always remember where we came from. Our kids must know we worked very, very hard to get where we are now, and there’s a lot of more work to do.”【1】Why did people stop in Dubai in the early 20th century?A.To relax.B.To buy oil.C.To go shopping.D.To do business.【2】Which of the following is NOTtrue?A.Dubai has created many man-made islands.B.There are many foreigners working in Dubai.C.Many international visitors come to Dubai every year.D.Dubai now gets money mainly from selling oil.【3】What does the underlined word “outnumber” mean?A.To be smaller in size than another group.B.To be more in number than another group.C.To be bigger in area than another group.D.To be smaller in area than another group.【4】In the last paragraph, what does the underlined part mean?A.We should always visit Dubai.B.We should learn from foreigners.C.We must always remember our past.D.We must only think about the future.【5】What’s the main idea of the passage?A.Dubai is growing very fast .B.Dubai was a big city before 1966.C.Many tall buildings are built in months.D.Many tourists come to relax on Dubai’s beaches.四、补充句子口语运用。
重庆八中2018-2019初三下学期寒假复习新学期入学测试(无听力部分)
重庆八中初2019级寒假复习检测英语试题(满分:150分考试时间:120分钟)第I卷(共95分)I.听力测试(略)30分。
II.单项选择。
(每小题1分,共15分)从A、B、C、D四个选项中选出可以填入空白处的正确答案,并把答题卡上对应题目的答案标号涂黑。
21.The art pieces in the museum made of ________ glass are worth watching. I’d like to buy _______ to add to the beauty of my new house.A. a; itB.\;oneC. a; oneD./;it22.—How old is your grandpa? He looks energetic.—Yeah, it is hard to imagine he is already in his __________.A. seventiesB. seventyC. seventiethD. seventieths23.He was advised to eat ________ hamburgers and drink ________ cola to keep fit.A. fewer; fewerB. less; lessC. fewer; lessD. less; fewer24.—Mom, how should I take the medicine?—oh, dear, I am pretty busy with my work right now. Please read the ________by yourself.A. instructionsB. predictionsC. productionsD. directions25.-—I heard that David was________ boy among all the boys.—Oh, really? You mean he was ________ than the others?A. more creative; more creativeB. the most creative; the most creativeC. more creative; the most creativeD. the most creative; more creative26.I prefer _______ rather than________ when I feel tired and stressed out.A. playing sports, listening to musicB. to play sports, listening to musicC. playing sports, listen to musicD. to play sports, listen to music27.—Did the fact cat notice that there was a mouse running toward the window?—I guess she didn’t. She__________ the fish happily with all her heart and soul.A.is eatingB. has eatenC. was eatingD.ate28.It’s a great pleasure for Peppy and George to help their parents _______their tent in the open fieldand spend a whole night sleeping in it there on the Children’s Day.A.look upB. take upC. put upD. call up29.---The number of old people in China is increasing rapidly.---I believe they _______ better care of in the future with the development of our country.A.can takeB. are takingC. are takenD. can be taken30.-----When do you plan to tell everyone the truth?-----Not ________ anyone finds out something is wrong.A.afterB. whenC. althoughD. until31.The Jaguar(捷豹)cars_______ well in China these years because the brand________ to an Indian company in 2008 that Chinese don’t truth.A.don’t sell; was soldB. aren’t sold; soldB.don’t sell; sold D. aren’t sold; was sold32.All the students_________ from school since the class ended except Jude. He is really hard-working.A.have leftB. has leftC. have been awayD. has been away33.Mr. Green has been coughing these days so his doctor________ him not to smoke.A.warnedB. keptC. suggestedD. had34.----Will Luckin Coffee finally take the place of Starbucks in our neighborhood?----__________.Because it is much cheaper and tastes great as well.A.I’m afraid notB. I’m afraid soC.I hope notD.I expect not35.------I heard many people were talking about the movie “The Wondering Earth”. I really wonder_________.------Probably the creativity of those Chinese who created the first hardcore science fiction.A.why was it so popularB. what it has made so popularB.what has made it so popular D. where it is so popularIII.完型填空。
重庆市第八中学2023-2024学年九年级下学期月考数学试题
重庆市第八中学2023-2024学年九年级下学期月考数学试题一、单选题1.实数5-的相反数是( )A .5B .5-C .15D .15- 2.下列几何体中,其俯视图与主视图完全相同的是( )A .B .C .D . 3.下列各式中,计算结果等于9a 的是( )A .36+a aB .36a a ⋅C .10a a -D .182÷a a 4.如图,把一块含有45︒角的直角三角板的两个顶点分别放在直尺的一组对边上,如果225∠=︒,那么1∠的度数是( )A .30︒B .25︒C .20︒D .15︒5.如图,是由一些小棒搭成的图案,按照这种方式摆下去,摆第9个图案所用小棒的数量为( )A .33B .36C .37D .416.五一假期,小明去游乐园游玩,坐上了他向往已久的摩天轮.摩天轮上,小明离地面的高度h (米)和他坐上摩天轮后旋转的时间t (分钟)之间的部分函数关系如图所示,则下列说法错误的是( )A .摩天轮旋转一周需要6分钟B .小明出发后的第3分钟和第9分钟,离地面的高度相同C .小明离地面的最大高度为42米D .小明出发后经过6分钟,离地面的高度为3米7.如图,以点O 为位似中心,把ABC V 放大2倍得到A B C '''V .下列说法错误的是( )A .ABC ABC '''∽△△B .:1:2AO AA '=C .AB A B ''∥D .直线CC '经过点O8.如图,AB 是O e 的直径,延长AB 至,C CD 切O e 于点D ,过点D 作DE AB ∥交O e 于点E ,连接BE .若12,15AB ABE =∠=︒,则BC 的长为( )A .3B .C .6D .69.如图,E 是正方形ABCD 的边CD 上的一点,连接AE ,点F 为AE 的中点,过点F 作AE的垂线分别交AD ,BC 于点M ,N ,连接AN ,若36AB DE ==,则A M N △的面积为( )A .8B .10C .12D .2010.依次排列的两个整式2a b -+,23a b -将第1个整式乘2再减去第2个整式,称为第1次操作,得到第3个整式65a b -+;将第2个整式乘2再减去第3个整式,称为第2次操作,得到第4个整式1011a b -;将第3个整式乘2再减去第4个整式,称为第3次操作,得到第5个整式2221a b -+;⋯,以此类推,下列4个说法,其中正确的结论有( )个. ①第6个整式为4243a b -+;②第n 个整式中a 系数与b 系数的和为1;③若2024a b ==,则前n 个整式之和为2024n .④第n 次与第1n +次操作后得到的两个整式中a 与b 所有系数的绝对值之和为32n +;A .0B .1C .2D .3二、填空题11.太阳中心的温度可达15500000℃,数据15500000用科学记数法表示为.12.计算1133-⎛⎫= ⎪⎝⎭. 13.现有三张正面分别标有数字1-,0,2的卡片,它们除数字不同外其余完全相同,将卡片背面朝上洗匀后,从中随机抽取一张,将卡片上的数字记为a ,放回洗匀后再随机抽取一张,将卡片上的数字记为b ,则满足0⋅=a b 的概率为.14.如图,点M 是反比例函数()0k y x x=<图像上的一点,过点M 作MN x ⊥轴于点N ,点P 在y 轴上,若MNP △的面积是2,则k =.15.如图,在等腰梯形ABCD 中,AD BC ∥,AB CD =,45A ∠=︒,6AD =,2BC =,以点C 为圆心,CB 长为半径画弧交CD 于点E ,则图中阴影部分面积为.16.如图所示,在ABC V 中,2AC AB =,BAC ∠的平分线交BC 于点D ,若3AB =,5CD =,则在ABC V 的周长为.17.若关于x 的不等式组153613x x x a ++⎧>⎪⎨⎪+≥+⎩的解集为3x >,关于y 的分式方程12233a y y --=--有非负整数解,则符合条件的所有整数a 的和为.18.一个四位正整数M ,各个数位均不为零,如果千位数字与个位数字之和的两倍等于百位数字与十位数字之和的三倍,且各个数位数字之和为20,则称M 为“第二十数”,那么百位数字和十位数字之和为,并规定()F M 等于M 的千位数字与百位数字之和的两倍与十位数字与个位数字之和的和,且()F M 为完全平方数;对于另一个“第二十数”N ,()G N 等于N 的前两个数字组成的两位数与后两个数字所组成的两位数的和,且()5G N 是一个整数,则N M -的最大值是.三、解答题19.计算:(1)()()232x x y x y -+- (2)22411369a a a a -⎛⎫-÷ ⎪+++⎝⎭ 20.如图,在ABCD Y 中,CE BC ⊥分别交AD ,BD 于点E ,F .(1)用尺规完成以下基本作图:过点A 作BC 的垂线,分别交BD ,BC 于点G ,H ,连接AF ,CG ;(保留作图痕迹,不写作法和结论)(2)根据(1)中所作图形,小南发现四边形AGCF 是平行四边形,并给出了证明,请你补全证明过程.证明:∵四边形ABCD 是平行四边形.∴AB CD =,①,∴ABG CDF ∠=∠.∵AH BC ⊥,CE BC ⊥,∴AHB ECB ∠=∠=②度,∴AG CF ∥,∴BGA EFB ∠=∠.又∵③,∴BGA DFC ∠=∠,在△ABG 和△CDF 中,ABG CDE BGA DFC AB CB ∠=∠⎧⎪∠=∠⎨⎪=⎩,∴()ABG CDF AAS ∆∆≌. ∴④,又∵AG CF ∥,∴四边形AGCF 是平行四边形.21.学校开展校本知识竞赛活动,现从八年级和九年级参与竞赛的学生中各随机选出20名同学的成绩进行分析(单位:分,满分100分),将学生竞赛成绩分为,,,A B C D 四个等级,分别是::70A x <,7080809090100Bx C x D x ≤<≤<≤≤∶,∶,∶. 下面给出了部分信息:其中,八年级学生的竞赛成绩为:66,75,76,78,79,81,82,83,84,86,86,86,88,90,91,92,94,95,96,96;九年级等级C的学生成绩为:81,82,83,86,87,88,88.两组数据的平均数、中位数、众数如表所示:根据以上信息,解答下列问题(1)填空:a=______,b=______,m=______;(2)根据以上数据,你认为在此次知识竞赛中,哪个年级的成绩更好?请说明理由(一条理由即可);(3)若八年级有600名学生参赛,九年级有800名学生参赛,请估计两个年级参赛学生中成绩优秀(大于或等于90分)的学生共有多少人?22.某工厂加工生产大,小两种型号的齿轮,每名工人每天只能生产一种型号的齿轮.一名熟练工每天生产的小齿轮数量是大齿轮的43,并且生产240个大齿轮所用的时间比生产同样数量的小齿轮要多用10天(1)求一名熟练工每天可以生产多少个大齿轮;(2)该工厂原有15名熟练工,由于订单激增,工厂需要招聘一批新工人,已知新工人每人每天可以生产3个大齿轮或5个小齿轮,工厂决定派3名熟练工带领一部分新工人一起生产大齿轮,其余工人全部生产小齿轮.已知2个大齿轮与3个小齿轮刚好配套.若一共招聘了28名新工人,问安排多少名新工人生产大齿轮,才能使得该工厂每天生产的大,小齿轮刚好配套?23.如图1,在等腰ABC V 中,10AB AC ==,16BC =,D 为底边BC 的中点,点P 从A 点出发以每秒1个单位长度的速度向终点B 运动,动点Q 从C 点出发,以每秒2个单位长度的速度;沿着C A B →→的路线运动,设运动时间为t ,连接AD ,DP ,DQ ,记ADP △的面积为1y ,记CDQ V的面积为2y ,请解答下列问题:(1)请直接写出1y ,2y 与t 之间的函数关系式以及对应的t 的取值范围;并在如图2所示的平面直角坐标系中分别画出1y ,2y 的函数图象;(2)观察2y 的函数图象,写出函数2y 的一条性质;(3)根据图象,直接写出当12y y ≥时,t 的取值范围.24.如图是体育公园步道示意图.从A 处和得点B 在北偏东45︒,测得点C 在北偏东75︒,在点C 处测得点B 在北偏西45︒,1800AB =米.(1)求步道AC 的长度(结果保留根号);(2)游客中心Q 在点A 的正东方向,步道AC 与步道BQ 交于点P ,测得45APQ ∠=︒,小明和爸爸分别从B 处和A 处同时出发去游客中心,小明跑步的速度是每分钟说明爸爸的速度要达到每分钟多少米,他俩可同时到达游客中心.(结果精确到0.1)(参考1.414≈ 1.732≈2.449)25.如图,抛物线()20y ax bx c a =++≠与x 轴交于点()2,0A -,点()3,0B ,交y 轴于点()0,3C .(1)求抛物线的解析式.(2)如图1,点P 在直线BC 上方抛物线上运动,过点P 作PE BC ⊥,PF x ⊥轴于点F ,求12AF +的最大值,以及此时点P 的坐标. (3)将原抛物线沿x 轴向右平移1个单位长度,新抛物线与y 轴交于点C ',点B 的对应点为B ',点N 是第一象限中新抛物线上一点,且点N 到y 轴的距离等于点A 到y 轴的距离的一半,问在平移后的抛物线上是否存在点M ,使得MNB C B N '''∠=∠,请写出所有符合条件的点M 的横坐标,并写出其中一个的求解过程.26.如图,将ABC V 的边AC 绕点C 逆时针旋转α 0°<α<360°至CD ,直线CD ,AB 交于点E ,连接AD ,直线AD ,BC 交于点F .(1)如图1,当ACB α<∠时,若45F ∠=︒,5AB AC ==,4CE =,求BC 的长;(2)如图2,当A C B α<∠时,若2BEC F ∠=∠,BAF BCD F ∠+∠=∠,猜想线段AD 与BF 之间存在的数量关系,并证明你的猜想;(3)如图3,当180180ACB α︒<<︒+∠时,若60BEC ∠=︒,6AB AC ==,点P 在线段AD 上且满足32AP CF=,G,H分别为线段CP,AP上两点,连接GH,将ACP△沿GH折叠使得点P的对应点P'落在AC上,连接PP',与折痕GH交于点O,请直接写出CP最小时,点O到AC的距离.。
2019年重庆市八中初三语文 第三次月考测试卷PDF版有答案
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也许这辈子它都会长 在 我 心 里 了———这 棵 沧 桑 的 老 树,在 我 懒 惰 的 时 候,在我遇到困难转身想 逃 的 时 候,在 我 祸 事 临 头 生 不 如 死 的 时 候,它 一 定 都会出来警醒我,拯救我,督 促 我 蓄 积 全 身 力 量 直 面 人 生 中 的 惨 淡 风 云、艰 难险阻,竭尽全力地让自己活得灿烂,一如它那样的精彩。 13.文章以“高山顶上一棵树”为线索,分别写了哪些内容?按照作者的行文
2019年重庆市八中初三语文
第三次月考测试卷
(全卷共四大题,满分 150分,120分钟)
一、基础知识积累与运用。(30分)
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人教版初中数学九年级下册第一次月考试卷(重庆八中
2018-2019学年重庆八中九年级(下)开学数学试卷一、选择题:(本大题12个小题,每小题4分,共48分)在每个小题的下面,都给出了A、B、C、D的四个答案,其中只有一个是正确的,请将答题卡上题号右侧正确答案所对应的框涂黑1.(4分)下列实数﹣3、、0、π中,无理数是()A.﹣3B.C.0D.π2.(4分)如图是两个等直径圆柱构成的“T”形管道,其左视图是()A.B.C.D.3.(4分)下列运算正确的是()A.x﹣2x=﹣x B.2x﹣y=﹣xyC.x2+x2=x4D.(x﹣1)2=x2﹣14.(4分)要使代数式有意义,则x的取值范围是()A.x>﹣1B.x≥﹣1C.x≠0D.x>﹣1且x≠0 5.(4分)如图,AB是⊙O的弦,OC⊥AB,交⊙O于点C,连接OA,OB,BC,若∠ABC =20°,则∠AOB的度数是()A.40°B.50°C.70°D.80°6.(4分)已知a为整数,且+2<,则a的值可能为()A.3B.8C.9D.127.(4分)如图,函数y=ax2﹣2x+1和y=ax﹣a(a是常数,且a≠0)在同一平面直角坐标系的图象可能是()A.B.C.D.8.(4分)如图,将△ABC沿BC边上的中线AD平移到△A'B'C'的位置,已知△ABC的面积为9,阴影部分三角形的面积为4.若AA'=1,则A'D等于()A.2B.3C.D.9.(4分)如图,在平面直角坐标系中,正方形ABCD的顶点A的坐标为(﹣1,1),点B 在x轴正半轴上,点D在第三象限的双曲线y=上,过点C作CE∥x轴交双曲线于点E,连接BE,则△BCE的面积为()A.5B.6C.7D.810.(4分)将正整数1至2018按一定规律排列如下表:平移表中带阴影的方框,方框中三个数的和可能是()A.2019B.2018C.2016D.201311.(4分)如图,将含有30°角的直角三角板ABC放入平面直角坐标系,顶点A、B分别落在x、y轴的正半轴上,∠OAB=60°,点A的坐标为(1,0).将三角板ABC沿x轴向右作无滑动的滚动(先绕点A按顺时针方向旋转60°,再绕点C按顺时针方向旋转90°…)当点B第一次落在x轴上时,则点B运动的路径与两坐标轴围成的图形面积是()A.B.+πC.+πD.+π12.(4分)若数a使得关于x的分式方程﹣=5有正数解,且使得关于y的不等式组有解,那么符合条件的所有整数a的个数为()A.1B.2C.3D.4二、填空题:(本大题6个小题,每小题4分一共24分)请将每小题的答案直接填在答题卡中对应的横线上13.(4分)计算:(3﹣π)0﹣(﹣)﹣2﹣tan30°=.14.(4分)已知△ABC与△DEF的相似比为2:3.若△ABC周长为12,则△DEF周长为15.(4分)关于x的方程x2﹣(n+2)x+n2﹣1=0有两个相等的实数根,则n=.16.(4分)如图,在△ABC中,CA=CB,∠ACB=90°,AB=4,点D为AB的中点,以点D为圆心作圆心角为90°的扇形DEF,点C恰在弧EF上,则图中阴影部分的面积为.17.(4分)张同学与王同学分别从A,B两地出发参加往直线往返运动,同时出发匀速相向而行;张同学的速度为120米/分,王同学的速度大于张同学:第一次相遇后,王同学在相遇处休息12分钟后以原速接着向A地运动,此时张同学未到达B地;两人分别到达后以原路原速返回,两人之间的距离y(米)与运动时间x(分)之间的关系如图所示,则第分钟时两人第二次相遇.18.(4分)某体育彩票投注站推出“英超、西甲、意甲”三大足球联赛的竞猜活动;猜对一场英超奖励3元,猜对一场西甲奖励2元,猜对一场意甲奖励1元;若干名球迷看到此活动后,分成三支小分队参与竞猜活动;第一小分队平均每人能猜对7场英超,5场西甲,3场意甲;第二小分队平均每人能猜对4场英超,4场西甲,2场意甲;第三小分队伍平均每人能猜对9场英超,6场西甲;这三支小分队在此活动中共获得奖励578元,其中通过猜对英超获得的奖励为339元,则第二支小分队的球迷人数为.三、解答题(本大题7个小题,每小题8分,共70分)解答时每小题必须给出必要的演算过程或推理步骤,画出必要的图形,请将解答过程书写在答题卡中对应的位置上19.(8分)计算:(1)(2a﹣b)2﹣(a﹣b)(4a﹣b)(2)1+÷(﹣x﹣1)20.(10分)某学校教学楼(甲楼)的顶部E和大门A之间挂了一些彩旗.小孟测得大门A距甲楼的距离AB是31m,在A处测得甲楼顶部E处的仰角是31°.(1)求甲楼的高度EB(精确到0.1m)(2)若小孟在甲楼楼底C处测得学校后面医院楼(乙楼)楼顶G处的仰角为40°,爬到甲楼楼顶F处测得乙楼楼顶G处的仰角为19°,求乙楼的高度GD及甲乙两楼之间的距离CD.(精确到0.1m)(cos31°≈0.86,tan31°≈0.60,cos19°≈0.95,tan19°≈0.34,cos40°≈0.7,tan40°≈0.84)21.(10分)在某次训练活动中,甲乙两位射击运动员的射击成绩(环)如表所示:甲:乙:(1)根据上述数据完成下表:(2)根据前面的统计分析,回答下列问题:平均数能较好地反映乙运动员的射击成绩吗?为什么?22.(10分)如图,P是半圆弧AB上一动点,连接P A、PB,过圆心O作OC∥BP交P A于点C,连接CB.已知AB=6cm,设O,C两点间距离为xcm,B,C两点间的距离为ycm.小东根据学习函数的经验,对函数y随自变量x的变化而变化的规律进行探究,下面是小东的探究过程,请补充完整:(1)通过取点、画图、冽量,得到了x与y的几组值,如表:说明:补全表格时相关数据取了近似值,保留一位小数(2)y与x的函数关系式为.(0≤x≤3,y>0)(3)建立直角坐标系,描出以补全后的表中各对应值为坐标的点,画出该函数的图象:23.(10分)华为手机与苹果手机深受消费者喜爱,某商户每周都用25000元购进250张华为手机壳和150张苹果手机壳.(1)商户在第一周销售时,每张华为手机壳的售价比每张苹果手机壳的售价的2倍少10元,且两种手机壳在一周之内全部售完,总盈利为5000元,商户销售苹果手机壳的价格每张多少元?(2)商户在第二周销售时,受到各种因素的影响,每张华为手机壳的售价比第一周每张华为手机壳的售价增加了a%,但华为手机壳的销售量比第一周华为手机壳的销售量下降了a%;每张苹果手机壳的售价比第一周毎张苹果手机壳的售价下降了a%,但苹果手机壳销售量与第一周苹果手机壳销售量相同,结果第二周的总销售额为30000元,求a (a>0)的值.24.(10分)如图,平行四边形ABCD中,BF⊥DC交DC于点F,且BF=AB,E点是BC 边上一点,连接AE交BF于G;(1)若AE平分∠DAB,∠C=60°,BE=3,求BG的长;(2)若AD=BG+FC,求证:AE平分∠DAB.25.(10分)阅读与应用:同学们:你们已经知道(a﹣b)2≥0,即a2﹣2ab+b2≥0.∴a2+b2≥2ab(当且仅当a=b时取等号).阅读1:若a、b为实数,且a>0,b>0,∵(﹣)2≥0,∴a﹣2+b≥0∴a+b≥2(当且仅当a=b时取等号).阅读2:若函数y=x+(m>0,x>0,m为常数),由阅读1结论可知:x+≥2即x+≥2,∴当x=,即x2=m,∴x=(m>0)时,函数y=x+的最小值为2.阅读理解上述内容,解答下列问题:问题1:若函数y=a﹣1+(a>1),则a=时,函数y=a﹣1+(a>1)的最小值为;问题2:已知一个矩形的面积为4,其中一边长为x,则另一边长为,周长为2(x+),求当x=时,周长的最小值为;问题3:求代数式(m>﹣1)的最小值.四、解答题(本大题1个小题,共8分)解答时每小题必须给出必要的演算过程或推理步骤,画出必要的图形,请将解答过程书写在答题卡中对应的位置上26.(10分)如图1,抛物线y=﹣x2+x+2与x轴交于A,B两点(点A在点B 右侧),与y轴交于点C,点D是抛物线的顶点,连接AD、BD.(1)如图1,连接AC、BC,若点P是直线AC上方抛物线上一动点,过点P作PE∥BC 交AC于点E,作PQ∥y轴交AC于点Q,当△PQE周长最大时,若点M在y轴上,点N在x轴上,求PM+MN﹣AN的最小值;(2)如图2,点G为x轴正半轴上一点,且OG=OC,连接CG,过点G作GH⊥AC于点H,将△CGH统点O顺时针旋转α(0°<α<180°),记旋转中的△CGH为△C′G′H′,在旋转过程中,直线C′G′,G′H′分别与直线AC交于点M,N,△G′MN能否成为等腰三角形?若能请直接写出所有满足条件的α的值;若不能,请说明理由.2018-2019学年重庆八中九年级(下)开学数学试卷参考答案与试题解析一、选择题:(本大题12个小题,每小题4分,共48分)在每个小题的下面,都给出了A、B、C、D的四个答案,其中只有一个是正确的,请将答题卡上题号右侧正确答案所对应的框涂黑1.(4分)下列实数﹣3、、0、π中,无理数是()A.﹣3B.C.0D.π【分析】由于无理数就是无限不循环小数,利用无理数的定义即可判定选择项.【解答】解:实数﹣3、、0、π中,无理数只有π,故选:D.【点评】本题主要考查学生对无理数和有理数定义的理解及区分.初中范围内学习的无理数有:π,2π等;开方开不尽的数;以及像0.1010010001…,等有这样规律的数.2.(4分)如图是两个等直径圆柱构成的“T”形管道,其左视图是()A.B.C.D.【分析】根据从左边看得到的图形是左视图,可得答案.【解答】解:从左边看如图,故选:B.【点评】本题考查了简单组合体的三视图,从左边看得到的图形是左视图.3.(4分)下列运算正确的是()A.x﹣2x=﹣x B.2x﹣y=﹣xyC.x2+x2=x4D.(x﹣1)2=x2﹣1【分析】根据整式的运算法则即可求出答案.【解答】解:(B)原式=2x﹣y,故B错误;(C)原式=2x2,故C错误;(D)原式=x2﹣2x+1,故D错误;故选:A.【点评】本题考查整式的运算法则,解题的关键是熟练运用整式的运算法则,本题属于基础题型.4.(4分)要使代数式有意义,则x的取值范围是()A.x>﹣1B.x≥﹣1C.x≠0D.x>﹣1且x≠0【分析】根据二次根式有意义,分式有意义,可得答案.【解答】解:依题意得:x+1>0,解得x>﹣1.故选:A.【点评】本题考查了二次根式有意义的条件,被开方数是非负数,且分式的分母不能为零.5.(4分)如图,AB是⊙O的弦,OC⊥AB,交⊙O于点C,连接OA,OB,BC,若∠ABC =20°,则∠AOB的度数是()A.40°B.50°C.70°D.80°【分析】根据圆周角定理得出∠AOC=40°,进而利用垂径定理得出∠AOB=80°即可.【解答】解:∵∠ABC=20°,∴∠AOC=40°,∵AB是⊙O的弦,OC⊥AB,∴∠AOC=∠BOC=40°,∴∠AOB=80°,故选:D.【点评】此题考查圆周角定理,关键是根据圆周角定理得出∠AOC=40°.6.(4分)已知a为整数,且+2<,则a的值可能为()A.3B.8C.9D.12【分析】根据a为整数,且+2<,可以求得a的值,本题得以解决.【解答】解:∵a为整数,且+2<,∴,∴a≤4且a为整数,故选:A.【点评】本题考查算术平均数、估算无理数的大小,解答本题的关键是可以估算出a的取值范围.7.(4分)如图,函数y=ax2﹣2x+1和y=ax﹣a(a是常数,且a≠0)在同一平面直角坐标系的图象可能是()A.B.C.D.【分析】可先根据一次函数的图象判断a的符号,再判断二次函数图象与实际是否相符,判断正误即可.【解答】解:A、由一次函数y=ax﹣a的图象可得:a<0,此时二次函数y=ax2﹣2x+1的图象应该开口向下,故选项错误;B、由一次函数y=ax﹣a的图象可得:a>0,此时二次函数y=ax2﹣2x+1的图象应该开口向上,对称轴x=﹣>0,故选项正确;C、由一次函数y=ax﹣a的图象可得:a>0,此时二次函数y=ax2﹣2x+1的图象应该开口向上,对称轴x=﹣>0,和x轴的正半轴相交,故选项错误;D、由一次函数y=ax﹣a的图象可得:a>0,此时二次函数y=ax2﹣2x+1的图象应该开口向上,故选项错误.故选:B.【点评】本题考查了二次函数以及一次函数的图象,解题的关键是熟记一次函数y=ax﹣a在不同情况下所在的象限,以及熟练掌握二次函数的有关性质:开口方向、对称轴、顶点坐标等.8.(4分)如图,将△ABC沿BC边上的中线AD平移到△A'B'C'的位置,已知△ABC的面积为9,阴影部分三角形的面积为4.若AA'=1,则A'D等于()A.2B.3C.D.【分析】由S△ABC=9、S△A′EF=4且AD为BC边的中线知S△A′DE=S△A′EF=2,S△ABD =S△ABC=,根据△DA′E∽△DAB知()2=,据此求解可得.【解答】解:如图,∵S△ABC=9、S△A′EF=4,且AD为BC边的中线,∴S△A′DE=S△A′EF=2,S△ABD=S△ABC=,∵将△ABC沿BC边上的中线AD平移得到△A'B'C',∴A′E∥AB,∴△DA′E∽△DAB,则()2=,即()2=,解得A′D=2或A′D=﹣(舍),故选:A.【点评】本题主要平移的性质,解题的关键是熟练掌握平移变换的性质与三角形中线的性质、相似三角形的判定与性质等知识点.9.(4分)如图,在平面直角坐标系中,正方形ABCD的顶点A的坐标为(﹣1,1),点B 在x轴正半轴上,点D在第三象限的双曲线y=上,过点C作CE∥x轴交双曲线于点E,连接BE,则△BCE的面积为()A.5B.6C.7D.8【分析】作辅助线,构建全等三角形:过D作GH⊥x轴,过A作AG⊥GH,过B作BM ⊥HC于M,证明△AGD≌△DHC≌△CMB,根据点D的坐标表示:AG=DH=﹣x﹣1,由DG=BM,列方程可得x的值,表示D和E的坐标,根据三角形面积公式可得结论.【解答】解:过D作GH⊥x轴,过A作AG⊥GH,过B作BM⊥HC于M,设D(x,),∵四边形ABCD是正方形,∴AD=CD=BC,∠ADC=∠DCB=90°,易得△AGD≌△DHC≌△CMB(AAS),∴AG=DH=﹣x﹣1,∴DG=BM,∵GQ=1,DQ=﹣,DH=AG=﹣x﹣1,由QG+DQ=BM=DQ+DH得:1﹣=﹣1﹣x﹣,解得x=﹣2,∴D(﹣2,﹣3),CH=DG=BM=1﹣=4,∵AG=DH=﹣1﹣x=1,∴点E的纵坐标为﹣4,当y=﹣4时,x=﹣,∴E(﹣,﹣4),∴EH=2﹣=,∴CE=CH﹣HE=4﹣=,∴S△CEB=CE•BM=××4=7;故选:C.【点评】本题考查正方形的性质、全等三角形的判定和性质、反比例函数的性质等知识,解题的关键是灵活运用所学知识解决问题,学会构建方程解决问题.10.(4分)将正整数1至2018按一定规律排列如下表:平移表中带阴影的方框,方框中三个数的和可能是()A.2019B.2018C.2016D.2013【分析】设中间数为x,则另外两个数分别为x﹣1、x+1,进而可得出三个数之和为3x,令其分别等于四个选项中数,解之即可得出x的值,由x为整数、x不能为第一列及第八列数,即可确定x值,此题得解.【解答】解:设中间数为x,则另外两个数分别为x﹣1、x+1,∴三个数之和为(x﹣1)+x+(x+1)=3x.根据题意得:3x=2019、3x=2018、3x=2016、3x=2013,解得:x=673,x=672(舍去),x=672,x=671.∵673=84×8+1,∴2019不合题意,舍去;∵672=84×8,∴2016不合题意,舍去;∵671=83×8+7,∴三个数之和为2013.故选:D.【点评】本题考查了一元一次方程的应用以及规律型中数字的变化类,找准等量关系,正确列出一元一次方程是解题的关键.11.(4分)如图,将含有30°角的直角三角板ABC放入平面直角坐标系,顶点A、B分别落在x、y轴的正半轴上,∠OAB=60°,点A的坐标为(1,0).将三角板ABC沿x轴向右作无滑动的滚动(先绕点A按顺时针方向旋转60°,再绕点C按顺时针方向旋转90°…)当点B第一次落在x轴上时,则点B运动的路径与两坐标轴围成的图形面积是()A.B.+πC.+πD.+π【分析】点B第一次落在x轴上时,点B运动的路径与两坐标轴围成的图形面积=S△AOB+S+S扇形ABB′+S扇形C′B′B″.△AC′B′【解答】解:在Rt△ABC中,∵OA=1,∠ABO=30°,∴AB=2,OB=∵∠ABC=30°,∠ACB=90°,∴AC=1,BC=,∴点B第一次落在x轴上时,点B运动的路径与两坐标轴围成的图形面积=S△AOB+S△AC′B′+S扇形ABB′+S扇形C′B′B″=++=+π,故选:B.【点评】本题考查轨迹,旋转变换,扇形的面积等知识,解题的关键是理解题意,灵活运用所学知识解决问题,属于中考常考题型.12.(4分)若数a使得关于x的分式方程﹣=5有正数解,且使得关于y的不等式组有解,那么符合条件的所有整数a的个数为()A.1B.2C.3D.4【分析】根据分式方程的解为正数即可得出a>﹣2且a≠2,根据不等式组有解,即可得:a<,找出所有的整数,a的个数为3.【解答】解:解方程﹣=5,得:x=,∵分式方程的解为正数,∴a+2>0,即a>﹣2,又x≠1,∴≠1,即a≠2,则a>﹣2且a≠2,∵关于y的不等式组有解,∴a﹣1≤y<6﹣2a,即a﹣1<6﹣2a,解得:a<,综上,a的取值范围是﹣2<a<,且a≠2,则符合题意的整数a的值有﹣1、0、1,3个,故选:C.【点评】本题考查了分式方程的解以及解一元一次不等式,根据分式方程的解为正数结合不等式组有解,找出﹣2<a<且a≠2是解题的关键.二、填空题:(本大题6个小题,每小题4分一共24分)请将每小题的答案直接填在答题卡中对应的横线上13.(4分)计算:(3﹣π)0﹣(﹣)﹣2﹣tan30°=﹣3﹣.【分析】根据零指数幂的性质a0=1(a≠0)和负指数幂的性质(a≠0)及特殊角的三角函数值求解即可.【解答】解:原式=1﹣4﹣,=﹣3﹣,故答案为﹣3﹣.【点评】此题主要考查了实数的运算,正确化简各数是解题的关键.14.(4分)已知△ABC与△DEF的相似比为2:3.若△ABC周长为12,则△DEF周长为18【分析】由△ABC与△DEF相似,相似比为2:3,可求得其周长比为:2:3,然后由△ABC的周长是12,求得△DEF的周长.【解答】解:∵△ABC与△DEF相似,相似比为2:3,∴周长比为:2:3,∵△ABC的周长是12,∴△DEF的周长是18.故答案为:18.【点评】此题考查了相似三角形的性质.此题比较简单,注意相似多边形的周长比等于相似比.15.(4分)关于x的方程x2﹣(n+2)x+n2﹣1=0有两个相等的实数根,则n=﹣2.【分析】根据“关于x的方程x2﹣(n+2)x+n2﹣1=0有两个相等的实数根”,结合判别式公式,得到△=0,整理得到关于n的一元一次方程,解之即可.【解答】解:根据题意得:△=(n+2)2﹣4(n2﹣1)=0,整理得:4n+8=0,解得:n=﹣2,故答案为:﹣2.【点评】本题考查了根的判别式,正确掌握判别式公式是解题的关键.16.(4分)如图,在△ABC中,CA=CB,∠ACB=90°,AB=4,点D为AB的中点,以点D为圆心作圆心角为90°的扇形DEF,点C恰在弧EF上,则图中阴影部分的面积为2.【分析】如图设DF交BC于M,DE交AC于N.由△BDM≌△CDN(ASA),推出S△BDM =S△DCN,可得S阴=S△ADC,由此即可解决问题.【解答】解:如图设DF交BC于M,DE交AC于N.∵CA=CB,∠ACB=90°,AD=DB,∴CD⊥AB,CD=DA=DB=2,∠DCN=∠B=45°,∴∠BDC=∠EDF=90°,∴∠BDF∠CDN,∴△BDM≌△CDN(ASA),∴S△BDM=S△DCN,∴S阴=S△ADC=×2×2=2,故答案为2.【点评】本题考查扇形的面积,直角三角形斜边中线的性质,等腰直角三角形的性质等知识,解题的关键是正确寻找全等三角形解决问题.17.(4分)张同学与王同学分别从A,B两地出发参加往直线往返运动,同时出发匀速相向而行;张同学的速度为120米/分,王同学的速度大于张同学:第一次相遇后,王同学在相遇处休息12分钟后以原速接着向A地运动,此时张同学未到达B地;两人分别到达后以原路原速返回,两人之间的距离y(米)与运动时间x(分)之间的关系如图所示,则第分钟时两人第二次相遇.【分析】设王同学的速度为a米/分,A、B两地距离为s米,由图象可得方程组,可求a、s的值,由第二次相遇时,两人的路程和为2s,可求解.【解答】解:设王同学的速度为a米/分,A、B两地距离为s米,由图象可得:解得:a=160,s=3360设第x分钟时两人第二次相遇120x+160(x﹣12)=3360×2x=故答案为:【点评】本题考查了一次函数的应用,读懂图象上点的所表示的具体意义是本题的关键.18.(4分)某体育彩票投注站推出“英超、西甲、意甲”三大足球联赛的竞猜活动;猜对一场英超奖励3元,猜对一场西甲奖励2元,猜对一场意甲奖励1元;若干名球迷看到此活动后,分成三支小分队参与竞猜活动;第一小分队平均每人能猜对7场英超,5场西甲,3场意甲;第二小分队平均每人能猜对4场英超,4场西甲,2场意甲;第三小分队伍平均每人能猜对9场英超,6场西甲;这三支小分队在此活动中共获得奖励578元,其中通过猜对英超获得的奖励为339元,则第二支小分队的球迷人数为15.【分析】设第一支小分队有x人,第二支小分队有y人,第三支小分队有z人,由这三支小分队在此活动中共获得奖励578元其中通过猜对英超获得的奖励为339元,即可得出关于x,y,z的三元一次方程组,利用②×9﹣①×13可得出33x+42y=795,结合x,y均为正整数即可求出x,y的值,再将其代入方程①中验证z值是否为正整数,此题得解.【解答】解:设第一支小分队有x人,第二支小分队有y人,第三支小分队有z人,依题意,得:,②×9﹣①×13,得:33x+42y=795,即11x+14y=265,∴y=.又∵x,y均为正整数,∴,.将x=5,y=15代入①,得:105+180+27z=339,解得:z=2;将x=19,y=4代入①,得:399+48+27z=339,解得:z=﹣4(不合题意,舍去).故答案为:15.【点评】本题考查了三元一次方程组的应用以及二元一次方程的应用,找准等量关系,正确列出三元一次方程组是解题的关键.三、解答题(本大题7个小题,每小题8分,共70分)解答时每小题必须给出必要的演算过程或推理步骤,画出必要的图形,请将解答过程书写在答题卡中对应的位置上19.(8分)计算:(1)(2a﹣b)2﹣(a﹣b)(4a﹣b)(2)1+÷(﹣x﹣1)【分析】(1)按照完全平方公式和平方差公式展开合并;(2)按照分式混合运算法则计算.【解答】解:(1)(2a﹣b)2﹣(a﹣b)(4a﹣b)=4a2﹣4ab+b2﹣(4a2﹣ab﹣4ab+b2)=4a2﹣4ab+b2﹣4a2+ab+4ab﹣b2=ab;(2)1+÷(﹣x﹣1)=1+=1+=1﹣=.【点评】本题考查整式运算和分式混合运算,灵活运用乘法公式和分式混合运算法则是解答的关键.20.(10分)某学校教学楼(甲楼)的顶部E和大门A之间挂了一些彩旗.小孟测得大门A 距甲楼的距离AB是31m,在A处测得甲楼顶部E处的仰角是31°.(1)求甲楼的高度EB(精确到0.1m)(2)若小孟在甲楼楼底C处测得学校后面医院楼(乙楼)楼顶G处的仰角为40°,爬到甲楼楼顶F处测得乙楼楼顶G处的仰角为19°,求乙楼的高度GD及甲乙两楼之间的距离CD.(精确到0.1m)(cos31°≈0.86,tan31°≈0.60,cos19°≈0.95,tan19°≈0.34,cos40°≈0.7,tan40°≈0.84)【分析】(1)在直角三角形ABE中,利用锐角三角函数定义求出BE的长即可;(2)过点F作FM⊥GD,交GD于M,在直角三角形GMF中,利用锐角三角函数定义表示出GM与GD,设甲乙两楼之间的距离为xm,根据题意列出方程,求出方程的解即可得到结果.【解答】解:(1)在Rt△ABE中,BE=AB•tan31°=31•tan31°≈18.6,则甲楼的高度为18.6m;(2)过点F作FM⊥GD,交GD于M,在Rt△GMF中,GM=FM•tan19°,在Rt△GDC中,DG=CD•tan40°,设甲乙两楼之间的距离为xm,FM=CD=x,根据题意得:x tan40°﹣x tan19°=18.60,解得:x=37.20,则乙楼的高度为31.25m,甲乙两楼之间的距离为37.20m.【点评】此题考查了解直角三角形的应用﹣仰角俯角问题,熟练掌握直角三角形的性质是解本题的关键.21.(10分)在某次训练活动中,甲乙两位射击运动员的射击成绩(环)如表所示:甲:乙:(1)根据上述数据完成下表:(2)根据前面的统计分析,回答下列问题:平均数能较好地反映乙运动员的射击成绩吗?为什么?【分析】(1)按照众数、中位数、平均数、方差的计算方法,即可得出结论;(2)根据乙射击成绩中含有两个极端值,受两个极端值的影响,导致乙射击成绩的方差较大,平均数高于大部分射击的成绩,故平均数不能较好地反映乙运动员的射击成绩.【解答】解:(1)甲射击成绩的平均数为(5×2+6×1+7×3+8×3+9×1)=7,方差为[(5﹣7)2+(5﹣7)2+(6﹣7)2+(7﹣7)2+(7﹣7)2+(7﹣7)2+(8﹣7)2+(8﹣7)2+(8﹣7)2+(9﹣7)2]=1.2,乙射击成绩的中位数为(6+9)=7.5,众数为10,故答案为:7,1.2,7.5,10;(2)平均数不能较好地反映乙运动员的射击成绩,理由是平均数受到极端数值的影响.【点评】此题主要考查统计的有关知识,解决问题的关键是掌握平均数、中位数、众数、方差的计算方法及意义.22.(10分)如图,P是半圆弧AB上一动点,连接P A、PB,过圆心O作OC∥BP交P A于点C,连接CB.已知AB=6cm,设O,C两点间距离为xcm,B,C两点间的距离为ycm.小东根据学习函数的经验,对函数y随自变量x的变化而变化的规律进行探究,下面是小东的探究过程,请补充完整:(1)通过取点、画图、冽量,得到了x与y的几组值,如表:说明:补全表格时相关数据取了近似值,保留一位小数(2)y与x的函数关系式为y=.(0≤x≤3,y>0)(3)建立直角坐标系,描出以补全后的表中各对应值为坐标的点,画出该函数的图象:【分析】(1)OC∥BP,则OC是△ABP的中位线,则BP=2x,PC=AC==,y==,将x=1或2代入即可求解;(2)由(1)得:y=;(3)描点即可.【解答】解:OC∥BP,则OC是△ABP的中位线,则BP=2x,PC=AC==,y==;(1)当x=1时,y≈3.5,x=2时,y≈4.58≈4.6,故:答案为3.5,4.6;(2)由(1)知,y=(0≤x≤3);答案为:y=;(3)如下图:【点评】本题为圆的综合题,主要考查三角形中位线和勾股定理的应用,难度不大.23.(10分)华为手机与苹果手机深受消费者喜爱,某商户每周都用25000元购进250张华为手机壳和150张苹果手机壳.(1)商户在第一周销售时,每张华为手机壳的售价比每张苹果手机壳的售价的2倍少10元,且两种手机壳在一周之内全部售完,总盈利为5000元,商户销售苹果手机壳的价格每张多少元?(2)商户在第二周销售时,受到各种因素的影响,每张华为手机壳的售价比第一周每张华为手机壳的售价增加了a%,但华为手机壳的销售量比第一周华为手机壳的销售量下降了a%;每张苹果手机壳的售价比第一周毎张苹果手机壳的售价下降了a%,但苹果手机壳销售量与第一周苹果手机壳销售量相同,结果第二周的总销售额为30000元,求a (a>0)的值.【分析】(1)设苹果手机壳的售价为每张x元,华为手机壳的售价为每张y元,根据“每张华为手机壳的售价比每张苹果手机壳的售价的2倍少10元,两种手机壳销售完的总盈利为5000元”,即可得出关于x,y的二元一次方程组,解之即可得出结论;(2)根据总销售额=销售单价×销售数量,即可得出关于a的一元二次方程,解之取其正值即可得出结论.【解答】解:(1)设苹果手机壳的售价为每张x元,华为手机壳的售价为每张y元,依题意,得:,解得:.答:苹果手机壳的售价为每张50元,华为手机壳的售价为每张90元.(2)依题意,得:90(1+a%)×250(1﹣a%)+50(1﹣a%)×150=30000,整理,得:3.75a2﹣75a=0,解得:a1=0(不合题意,舍去),a2=20.答:a的值为20.【点评】本题考查了一元二次方程的应用以及二元一次方程组的应用,解题的关键是:(1)找准等量关系,正确列出二元一次方程组;(2)找准等量关系,正确列出一元二次方程.24.(10分)如图,平行四边形ABCD中,BF⊥DC交DC于点F,且BF=AB,E点是BC 边上一点,连接AE交BF于G;(1)若AE平分∠DAB,∠C=60°,BE=3,求BG的长;(2)若AD=BG+FC,求证:AE平分∠DAB.【分析】(1)利用等角对等边即可证明BA=BE,在直角△ABG中求的BG和AB的长,根据FG=BF﹣BG即可求解;(2)作CH⊥AB于点H,延长AH到I,使HI=BG,则BI=BG+FC,证明△ABG≌△CHI,得出∠I=∠AGB,∠4=∠2,再证明∠3=∠4,∠1=∠3,即可得出∠1=∠2.【解答】(1)解:∵四边形ABCD是平行四边形,∴AD∥BC,∠C=∠BAD=60°,CD∥AB,∴∠DAE=∠AEB,∵AE平分∠DAB,∴∠DAE=∠BAE=30°,∴∠AEB=∠BAE,∴AB=BE=3,∵BF⊥DC,∴∠DFB=90°,∵CD∥AB,∴∠ABF=90°,∴BG=AB•tan∠BAE=3×=;(2)证明:作CH⊥AB于点H,延长AH到I,使HI=BG.则四边形BFCH是矩形,CF=BH,CH=BF=AB.在△ABG和△CHI中,,∴△ABG≌△CHI(SAS).∴∠I=∠AGB,∠4=∠2,∵∠I=∠AGB=∠3+∠FBC,∠BCI=∠BCH+∠4,∵AD=BG+FC=HI+BH=BI,AD=BC,∴BC=BI,∴∠BCI=∠I,∵BF∥CH,∴∠FBC=∠BCH,∴∠3=∠4.∵AD∥BC,∴∠1=∠3,而∠2=∠4,∴∠1=∠2,∴AE平分∠DAB.【点评】本题考查了平行四边形的性质,全等三角形的判定与性质,平行线的判定与性质,等腰三角形的性质等知识,正确作出辅助线是解题的关键.25.(10分)阅读与应用:同学们:你们已经知道(a﹣b)2≥0,即a2﹣2ab+b2≥0.∴a2+b2≥2ab(当且仅当a=b时取等号).阅读1:若a、b为实数,且a>0,b>0,∵(﹣)2≥0,∴a﹣2+b≥0∴a+b≥2(当且仅当a=b时取等号).阅读2:若函数y=x+(m>0,x>0,m为常数),由阅读1结论可知:x+≥2即x+≥2,∴当x=,即x2=m,∴x=(m>0)时,函数y=x+的最小值为2.阅读理解上述内容,解答下列问题:问题1:若函数y=a﹣1+(a>1),则a=4时,函数y=a﹣1+(a>1)的最小值为6;问题2:已知一个矩形的面积为4,其中一边长为x,则另一边长为,周长为2(x+),求当x=2时,周长的最小值为8;问题3:求代数式(m>﹣1)的最小值.【分析】(1)由阅读2得到a﹣1=时,函数y=a﹣1+(a>1)取最小值;(2)同(1)方法x=2时周长取到最小值;(3)先将处理成m+1+,同(1)的方法得出结论;【解答】解:问题1,由阅读2知,a﹣1=时,即:a=4时,函数y=a﹣1+(a>1)的最小值是2=6,答案为4,6;问题2,由阅读2知,x==2时,周长为2(x+)的最小值是2×2=8,故答案为2,8;(3)===m+1+,∴当m+1=时,即m=1时,(m>﹣1)最小值是2=4.【点评】此题是反比例函数题,函数极值的确定方法,读懂材料是解本题的关键,难点是理解和运用材料得到的结论解决问题.四、解答题(本大题1个小题,共8分)解答时每小题必须给出必要的演算过程或推理步骤,画出必要的图形,请将解答过程书写在答题卡中对应的位置上26.(10分)如图1,抛物线y=﹣x2+x+2与x轴交于A,B两点(点A在点B 右侧),与y轴交于点C,点D是抛物线的顶点,连接AD、BD.(1)如图1,连接AC、BC,若点P是直线AC上方抛物线上一动点,过点P作PE∥BC 交AC于点E,作PQ∥y轴交AC于点Q,当△PQE周长最大时,若点M在y轴上,点N在x轴上,求PM+MN﹣AN的最小值;(2)如图2,点G为x轴正半轴上一点,且OG=OC,连接CG,过点G作GH⊥AC于。
重庆八中2019-2020学年九年级下学期第一次月考(3月)数学试题(word版+答案解析)
重庆八中2019—2020学年度(下)初三年级第一次月考数学试题一、选择题:1.一个几何体的主视图、左视图和俯视图都是圆,则这个几何体是( ) A. 圆柱 B. 球 C. 圆锥 D. 正方体2.若12x +在实数范围内有意义,则x 的取值范围在数轴上表示正确的是( ) A.B.C.D.3.下列各线段中,能与长为4,6的两线段组成三角形的是( ) A. 2 B. 8 C. 10D. 124.下列命题正确的是( ) A. 若锐角α满足1sin 2α=,则60α=︒ B. 在平面直角坐标系中,点()2,1关于x 轴的对称点为()2,1-C. 两条直线被第三条直线所截,同旁内角互补D. 相似三角形周长之比与面积之比一定相等5.中国明代数学著作《算法统宗》中有这样一首古诗:“巍巍古寺在山中,不知寺内有多僧?三百六十四只碗,恰好用尽不用争,三人共餐一碗饭,四人共尝一碗羹,请问先生能算者,算出寺内几多僧?”其大意是,某古寺用餐,3个和尚吃一碗饭,4个和尚合分一碗汤,一共用了364只碗,问有多少个和尚?根据题意,可以设和尚的个数为x ,则得到的方程是( ) A .34364x x +=B.1136434x x += C.143643x x += D. 133644x x += 6.如果22x y -=,那么代数式224y x yx x x ⎛⎫+-÷ ⎪⎝⎭的值为( ) A. 2-B.2C. 2D. -27.若点()2,A m -,()3,B n 都在二次函数225y ax ax =-+(a 为常数,且0a >)的图象上,则m 和n 的大小关系是( ) A. m n >B. m n =C. m n <D. 以上答案都不对8.最早对勾股定理进行证明的,是三国时期吴国的数学家赵爽,赵爽创制了一幅“勾股圆方图”,用数形结合的方法,给出了勾股定理的详细证明.在这幅“勾股圆方图”中,以弦为边长得到的正方形是由4个全等的直角三角形再加上中间的小正方形组成的.设直角三角形的两直角边长为,a b ,且满足()223a b +=,若小正方形的面积为11,则大正方形的面积为( ) A. 15B. 17C. 30D. 349.重庆移动为了提升新型冠状肺炎“停课不停学”期间某片区网络信号,保证广大师生网络授课、听课的质量,临时在坡度为1:2.4i =的山坡上加装了信号塔PQ (如图所示),信号塔底端Q 到坡底A 的距离为3.9米.同时为了提醒市民,在距离斜坡底4.4米的水平地面上立了一块警示牌MN .当太阳光线与水平线成53°角时,测得信号塔PQ 落在警示牌上的影子EN 长为3米,则信号塔PQ 的高约为(tan53°≈1.3)( ).A. 10.4B. 11.9C. 11.4D. 13.410.如图,在ABC V 中,2B C ∠=∠,以点A 为圆心,AB 长为半径作弧,交BC 于点D ,交AC 于点G ; 再分别以点B 和点D 为圆心,大于12BD 的长为半径作弧,两弧相交于点E ,作射线AE 交BC 于点F .若以点G 为圆心,GC 长为半径作两段弧,一段弧过点C ,而另一段弧恰好经过点D ,则此时FAC ∠的度数为( )A. 54°B. 60°C. 66°D. 72° 11.已知,甲、乙两人分别从A B 、两地出发,相向而行,已知甲先出发4分钟后,乙才出发,他们两人在A B 、之间的C 地相遇,相遇后,甲立即返回A 地,乙继续向A 地前行.甲到达A 地时停止行走,乙到达A 地是也停止行走,在整个行走过程中,甲、乙两人均保持各自的速度匀速行走,甲、乙两人相距的路程y (米)与甲出发的时间x (分钟)之间的关系如图所示,则下列结论错误的是( )A. A B 、两地相距2480米B. 甲的速度是60米/分钟,乙的速度是80米/分钟C. 乙出发17分钟后,两人在C 地相遇D. 乙到达A 地时,甲与A 地相距的路程是300米.12.若整数a 既使得关于x 的分式方程6211ax xx x --=--有整数解,又使得关于,x y 的方程组1521ax y x y -=⎧⎨-=-⎩ 的解为正数,则符合条件的所有a 的个数为( )A. 1B. 2C. 3D. 4二、填空题:13.11123tan 3022-⎛⎫-︒+-= ⎪⎝⎭__________.14.若正多边形的一个外角是72°,则该正多边形的内角和是__________.15.如图,四边形OABC 的顶点O 为坐标原点,以O 为位似中心,作出四边形111OA B C 与四边形OABC 位似,若()6,0A ,的对应点为()14,0A ,四边形OABC 的面积为27,则四边形111OA B C 的面积为__________.16.如图,在每个小正方形的边长为1的网格图形中,每个小正方形的顶点称为格点,任意三个格点组成的三角形面积如果不小于1则称为“离心三角形”,而如果面积恰好等于1则称为“环绕三角形”.,A B 是网格图形中已知的两个格点,点C 是另一个格点,且满足ABC V 是“离心三角形”,则ABC V 是“环绕三角形”的概率是__________.17.如图,在平面直角坐标系内,O 为坐标原点,点A 为直线21y x =+上一动点,过A 作AC x ⊥轴,交x 轴于点C (点C 在原点右侧),交双曲线1yx=于点B ,且4AC BC +=,则当OAB V 存在时,其面积为__________.18.如图,在Rt ABC V 中,9016ACB AC ∠=︒=,,将Rt ABC V 绕点B 顺时针旋转一定角度后得到111Rt A B C △,连接11CC AA ,,过点A 作AM AC ⊥交11A C 于点D ,若111135CC AA BC C D ==,,且AD BC <,则AD 的长为__________.三、解答题:19.(1)解不等式组:() 3252132xxx x⎧--≥⎪⎨>-⎪⎩;(2)化简:()()223x y x x y---.20.如图,AB为Oe的直径,弦CD AB⊥,垂足为E,45CD=,连接,2,OC OE EB F=为圆上一点,过点F作圆的切线交AB的延长线于点G,连接,BF BF BG=.(1)求Oe的半径;(2)求证:AF FG=;(3)求阴影部分的面积.21.据第四次全国经济普查的数据表明,中国经济已经开始由高速增长转向高质量发展,供给侧结构性改革初见成效.各地产品质量监管部门也严抓质量,整顿生产,促进经济更好发展.某质量监管部门对甲、乙两家工厂生产的同种产品进行检测,分别随机抽取50件产品,并对产品的某项关键质量指标做检测,获得质量指标检测值t,对数据整理分析的部分信息如下:【1】甲、乙两工厂的样本数据频数分布表如下:工厂类别7585t≤<8595t≤<95105t≤<105115t≤<115125t≤<合计甲工厂频数0 a10 3 50频率0.00 0.24 b0.06 1.00乙工厂频数 3 15 13 18 1 50频率0.06 0.30 0.26 0.36 0.02 1.00其中,乙工厂样品质量指标检测值在范围内的数据分别是:100,98,98,99,102,97,95,101,98,100,98,102,104【2】两工厂样本数据的部分统计数据如下:平均数中位数众数方差甲工厂97.3 99.5 96 78.3乙工厂97.3 c107 1354根据以上信息,回答下列问题:(1)表格中,a = ,b = ,c = ;(2)已知质量指标检测值在85115t ≤<内,属于合格产品.若乙工厂某批次产品共1万件,估计该批产品中不合格的有多少件?(3)若质量指标检测值为100时为优秀,偏离100越小,产品质量越高.现有一家公司需大量采购该种产品,根据题目给定的数据,你认为选择哪家工厂的产品更好?请说明理由.22.如图,已知矩形,3,6ABCD AB cm AD cm ==,点M 为线段BC 上一动点,沿线段BC 由B 向C 运动,连接AM ,以AM 为边向右侧作正方形AMNP ,连接,CN DN ,设M 的路程即BM 的长为xcm ,C N 、间的距离为1y cm ,D N 、间的距离为2y cm .数学兴趣小组的小刚根据学习函数的经验,分别对函数12,y y 随自变量x 的变化而变化的规律进行探究,过程如1x /x cm0 1 2 3 4 5 6 1/y cm 32.22a34.115.396.722/y cm4.24 2.81 1.39b2.84 4.26其中,a = , ;(2)在同一平面黄子佼坐标系中,描点()()12,,,x y x y ,并画出12,y y 的函数图像; (3)当CDN △为等腰三角形时,BM 的长度约为 .23.随着人们的生活水平不断提高,人们越来越注重生活品质,注重食物营养.水果罐头在保存鲜度和营养方面得天独厚,仅次于现摘水果,水果罐头不仅果肉好吃,水果的本色本味完全融入到糖水中,罐头水的风味甚至比果汁还要浓郁.某车间生产以甲、乙两种水果为原料的某种罐头,在一次进货中得知,花费1.8万元购进的甲种水果与2.4万元购进的乙种水果质量相同,乙种水果每千克比甲种水果多2元. (1)求甲、乙两种水果的单价;水果成本之外,其他所有成本是水果成本的57的还要多3元.调查发现,以28元的定价进行销售,每天只能卖出3000听,超市对它进行促销,每降低1元,平均每天可多卖出1000听,当售价为多少元时,利润最大?最大利润为多少?(3)若想使得该种罐头的销售利润每天达到6万元,并且保证降价的幅度不超过定价的15%,每听罐头的价钱应为多少钱?24.如图,抛物线243y ax x c =-+与x 轴交于A B 、 两点,与y 轴交于C 点,连接AC ,已知()1,0B -,且抛物线经过点()2,2D -.(1)求抛物线的解析式;(2)若点E 是抛物线上位于x 轴下方的一点,且12ACE ABC S S =△△,求E 的坐标; (3)若点P 是y 轴上一点,以P A C 、、三点为顶点的三角形是等腰三角形,求P 点的坐标.25.请阅读下列材料:问题:已知方程2+10x x -=,求一元二次方程,使它的根分别是已知方程根的2倍. 解:设所求方程的根为y ,则2y x =,所以2y x =. 把2y x =代入已知方程,得21022y y ⎛⎫+-= ⎪⎝⎭ 化简,得2240y y +-= 故所求方程为2240y y +-=.这种利用方程根的代换求新方程的方法,我们称为“换根法”.请用阅读材料提供的“换根法...”求新方程(要求:把所求方程化为一般形式). (1)已知方程210x x +-=,求一个一元二次方程,使它的根分别是已知方程根的相反数,则所求方程为: .(2)已知关于x 的一元二次方程20ax bx c ++=有两个不等于零的实数根,求一个一元二次方程,使它的根分别是已知方程根的倒数;(3)已知关于x 的方程20x mx n -+=有两个实数根,求一个方程..,使它的根分别是已知方程根的平方.26.在ABC V ,CDE △中,90BAC DEC ∠=∠=︒,连接BD ,F 是BD 中点,连接,AF EF(1)如图1,若,,A C E 三点在同一直线上,45ABC EDC ∠=∠=︒,已知35AB DE ==,,求线段AF 的长;(2)如图2,若45ABC EDC ∠=∠=︒,求证:AEF V 为等腰直角三角形; (3)如图3,若30ABC EDC ∠=∠=︒,请判断AEF V 的形状,并说明理由.(3)由(2)得,()2100056400060000W m =--+= ,解得:7m =或3,但是,降价幅度不超过定价的15%,即m ≤28×15%, 4.2m ∴≤ ,3m ∴= ,∴售价为28325-= ,答:售价为25元时,利润为6万元.24.【解析】(1)将点()1,0B -,点()2,2D -代入243y ax x c =-+ , 可得4+038423a c a c ⎧+=⎪⎪⎨⎪-+=-⎪⎩,解得232a c ⎧=⎪⎨⎪=-⎩ , ∴抛物线解析式:224233y x x =-- ; (2)当0y =时,2242033x x --= , 解方程2242033x x --=,得121,3x x =-= , ()3,0A ∴ ,4AB ∴= ,当0x =时,2y =- ,()0,2C ∴- ,1142422ABC c S AB y ∴=⋅=⨯⨯=△ , 设:Ac l y kx b =+,将点()()3,0,0,2A C -代入y kx b =+ ,得302k b b +=⎧⎨=-⎩,解得232k b ⎧=⎪⎨⎪=-⎩ , 223y x ∴=- , 如图1,过点E 作x 轴的垂线交Ac l 于点F ,设点2,23F a a ⎛⎫- ⎪⎝⎭,点224,233E a a a ⎛⎫-- ⎪⎝⎭,其中13a -<< , 2223,1013222233,03ACE A c a a a S EF x x a a a a a ⎧--<<∴=-=-=⎨-+<<⎩V , 由12ACE ABC S S =△△ , 可得232a a -=或232a a -+= ,解得:13172a +=(舍),234317,1,22a a a -=== , ()1233171178,,1,,2,23E E E ⎛⎫--⎛⎫∴-- ⎪ ⎪ ⎪⎝⎭⎝⎭; (3)情形一:当点A 为等腰PAC V 的顶点时,AC AP =,如图2,,AC AP OA CP =⊥Q ,2CO OP ∴== ,∴点()10,2P ;情形二:当点C 为等腰PAC V 的顶点时,CA CP =,如图3,222313CA CP ==+=Q ,()()230,213,0,213P P ∴-+-- ;情形三:当点P 为等腰PAC V 的顶点时,PA PC =,如图4,过线段AC 的中点D 作垂线交y 轴于点P , 由中点坐标公式可得3,12D ⎛⎫- ⎪⎝⎭, PD AC ∴⊥ ,1AC PD k k ∴⋅=- , 又23AC k =Q , 32PD k ∴=- , 设PD 的解析式为32y x b =-+, 将3,12D ⎛⎫- ⎪⎝⎭代入32y x b =-+可得54b =, 35:24PD l y x ∴=-+ , 当0x =时,54y = ,450,4P ⎛⎫∴ ⎪⎝⎭;综上所述:()10,2P ,(20,2P-+,(30,2P -,450,4P ⎛⎫ ⎪⎝⎭. 25【解析】(1)设所求方程的根为y ,则y x =- ,所以x y =-.把x y =-代入已知方程,得,()()210y y -+--= ,化简,得210y y --= ,故所求方程为210y y --=;(2)设所求方程的根为y ,则()10y x x=≠,于是()10x y y =≠ , 把1x y =代入方程20ax bx c ++=,得2110a b c y y ⎛⎫+⋅+= ⎪⎝⎭, 去分母,得20a by cy ++= ,若0c =,有20ax bx +=,于是方程20ax bx c ++=有一个根为0,不符合题意,0c ∴≠ ,故所求方程为()200cy by a c ++=≠ ; (3)设所求方程的根为y ,则2y x =,所以x =,①当x =x =20n -=,即0y n -=;②当x =x = ((20m n -+=,即0y n +=∴所求方程为0y n -=或0y n +=.26【解析】(1)连接CF ,Q 在,Rt ABC Rt CDE △△中,45ABC EDC ∠=∠=︒ ,45,,ACB ECD AB AC ED CE ∴∠=∠=︒== ,,,A C E Q 三点在同一直线上,90BCD ∴∠=︒ ,F Q 为BD 中点,CF DF BF ∴== ,Q 在ACF V 和ABF V 中,AB AC AF AF BF CF =⎧⎪=⎨⎪=⎩,()ABF ACF SSS ∴△≌△ , 1452CAF CAB∴∠=∠=︒ , 同理:()1,452ECF EDF SSS CEF CED ∠=∠=︒△≌△ , AEF ∴V 等腰直角三角形,3,5AC AB CE DE ====Q ,2228,,2422AE EF AF AE AF AE ∴=+===(2)证明:取BC 中点M ,CD 的中点N ,连接,,,AM MF EN FN ,FQ为BD中点,FM∴为BCDV的一条中位线,1,2FM CD FM CD CN∴==P,∴四边形MCNE为平行四边形,,,CM FN MF CN CMF FNC==∠=∠,Q在Rt ABCV中,M为BC的中点,90,AMC AM CM∴∠=︒=,同理:90,ENC EN CN∠=︒=,,AM FN MF EN∴==,AMF AMC CMF ENC CNF FNE∠=∠+∠=∠+∠=∠,AMFQ△和FNEV中,AM FNAMF FNEMF NE=⎧⎪∠=∠⎨⎪=⎩,()AMF FNE SAS∴△≌△,AF EF∴=13∠=∠,()121803290 AFE MFN FNC ENC∠=∠-∠-∠=︒-∠-∠-∠=∠=︒Q,AEF∴V为等腰直角三角形,(3)证明:取BC的中点M,CD的中点N,连接,,,AM MF EN FN,FQ为BD中点,FM∴为BCDV的一条中位线,1,2FM CD FM CD CN∴==P,∴四边形MCNE为平行四边形,,,CM FN MF CN CMF FNC==∠=∠,Q在Rt ABCV中,M为BC的中点,∠ABC=30°60,AMC AM CM∴∠=︒=,同理:60,ENC EN CN ∠=︒= ,,AM FN MF EN ∴== ,AMF AMC CMF ENC CNF FNE ∠=∠+∠=∠+∠=∠, AMF Q △和FNE V 中,AM FN AMF FNE MF NE =⎧⎪∠=∠⎨⎪=⎩,()AMF FNE SAS ∴△≌△ ,AF EF ∴=,13∠=∠ ,()121803260AFE MFN FNC ENC ∠=∠-∠-∠=︒-∠-∠-∠=∠=︒Q , AEF ∴V 为等边三角形.。
重庆八中初2018级初三下期英语定时训练(三)无听力部分无答案
重庆八中初2018级初三(下)定时训练(三)英语试题第I卷(共95分)I.听力测试(共30分)略II.单项选择(每小题1分,共15分)21.Look! There’s 11-year-old boy students under the tree.A. aB. theC. anD. /22. The two sessions(两会)were held in March in Beijing. If you want to get further about it, you can search the Internet.A. informationB. newsC. messageD. words23. students enjoyed themselves yesterday in Happy Valley, Lijia, Chongqing.A. Two thousandsB. Two thousands ofC. Thousand ofD. Two thousand24.-Who taught the pop song?-Nobody. We learned it by .A. your, usB. yours, usC. you, ourselvesD. you, ourselves25. David is badly hurt, so he can move his legs now.A. hardB. hardlyC. difficultD. nearly26. You should pay attention to the traffic lights when you go the streets.A. pastB. throughC. overD. across27. It’s said that a new bridge in three months over the jialing River.A. was builtB. will buildC. would be buildD. will be built28.-Does the CD belong to Mary?-No, it be hers. Look, there’s name “Mike” on it.A.mustn’tB. mayC. can’tD. need29. The kites by hand are very popular with the foreigners. They sell very well.A.are madeB. to makeC. madeD. making30. After the people the fire, all of them felt tired out.A. put outB. put offC. put awayD. put on31. time you spend with other people, friends you’ll have.A. The more; the lessB. The less; the fewerC. The fewer; the moreD. The less; the less32.-When will the meeting begin?-It start until everybody .A. will; will arriveB. won’t; arrivesC. will; arrivesD. won’t; will arrive33.Study hard, you’ll achieve success in your exam.A. orB. butC. andD. neither34.There many trees in this forest, but now most of them have disappeared.A.are used to beB. used to haveed to beD. is used to35.We all wondered .A. that Tony got to school on time this morning.B. what’s the matter with Tony.C.whether Tony often walked to schoolD.whom was Tony talking withIII. 完型填空。
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重庆市八中2018-2019 学年度(下)初三年级月考I听力测试。
II单项选择。
21.--I hurt my leg by accident. Should I take X-ray? –Of course, you should. The doctor will usually check _X-ray you take first.A.an, \B.a, aC.an, theD.a, the22.--You’re playing the violin so beautifully! –Thank you! I practice it very hard every day so that I can be a one day.A.pianistB.dentistC.scientistD.musician23.—Uncle Lee, did you see my father? –Yes, I happened him at Yonghui supermarket half an hour ago.A.meetB.meetingC.metD.to meet24.My teacher Amy is a beautiful lady and looks much than her age because she does exercise a lot.A.niceB.energeticC.youngerD.older25.—What do you think of the science fiction movie ”The wondering Earth” made in China? –I found a great success for Chinese to make such a wonderful film like that.A.itB.it’sC.thatD.that’s26.visitors come to Chongqing to take cable cars(缆车)during the vacation because Chongqing has become a popular destination on the Internet(网红城市)now.A.ThousandB.ThousandsC.Thousand ofD.Thousands of27.—Haven’t you seen the sign” No Smoking In The Ronn”h ere? –Sorry, when I came in.I ‘ll put out the cigarette right away.A.I didn’t see it.B.I haven’t seen it.C.I will see it.D.I was seeing it.28.Remember not to go across the street the traffic light turns green.A.becauseB.afterC.whenD.until29.One of my familly rules is that I can’t watch TV unless my homework .A.was finishedB.is finishedC.will be finishedD.finishes30.—I’m so excited about Huawei’s new foldable(可折叠的)smartphone. Do you know ? –Very soon. We’ll see.A.how can I get oneB.how I can get oneC.when will it come outD.when it will come outIII.完型填空。
There was a man who had four sons. He wanted his sons to learn to not judge(下定论)things too quickly So he sent them each in 31 to go and look at a pear tree that was far away from their home. He sent his first born son to go in the winter, the second in the spring, the third in the summer, and the 32 son in the fall.When they had all gone and come back, he called them together to describe 33 they had seen. The first son said that the tree was ugly and bent ( 弯曲的). The second son said no—it 34 with green buds (f)and full of hope. The third son disagreed, he said it full of blossoms ( 花朵)that 35 so sweet, and it was the most beautiful thing he had ever seen. The last son disagreed with 36 of them: he said it was full of fruit, life and fulfillment(充实).The man then explained to his sons that they were all right, because they had each seen_ 37 one season in the trees’ life. He told them that they cannot judge a tree, or a person, by only one season, and that the essence ( 本 质 ), pleasure, joy, and love that 38 life can only be judged at the end, when all the seasons are up.If you give up 39 it's winter, you will miss the hope of your spring, the beauty ofyour summer, fulfillment of your fall. Don't let the pain of one season destroy the joy of 40 . 31. A. time 32. A. oldest 33. A. what 34. A. made 35. A looked 36. A. all37. A. like38. A. come in39.A. after40.A. the otherIV. 阅读理解。
B. turn B. eldest B. how B. was made B. felt B. none B.only B. come from B. before B. the othersC.home C. smartest C. who C.covered C. smelt C. either C. with e on C. when C. otherD.need D. youngest D. when D. was covered D. sound D. both D. out D. come true D. until D. others 41. Kelvin Grove Stale High School will start its next term .A. on May 6th .B. on July 11th .C. on August 1st .D.on September 11th .42. According o the form, which of the following sentences is TRUE?A. Edward doesn't do well in science.B. Edward can't sing songs well.C. Edard studies two languages at school.D. Edward likes pop songs so much43. The form (表格)above is about .A .a studying plan of Edward Scott. B. a teaching program of I vy.C. a school report of Edward Scott.D.a working problem of M. L. M artin.BMessages from ThailandMessage1: March 24thHi everybody,Greetings from Thailand! We arrived here tired, but excited. This is our first trip to Asia and the friendliness of the people is amazing. All the different sights and smells make us feel like trying the food. We are looking forward to eating Thai food for dinner tonight. The owners have told us about some places that we shouldn't miss. We plan to stay here in Bangkok(曼谷)for a few days, and then travelled to the north.Message 2: March 27thHi everybody,Thailand is fantastic! The different Buddha status ( 佛像)are wonderful to look at. We visited Jatujak Market in Bangkok. Everything there was so colorful, and we took lots of photographs! Later today we took the train north. Well stay in Chien mai( 清迈)for four days, and then catch a bus to Chiang Rai (清莱).Were going to go hiking in the mountains.Message 3: April 4thHi everybody,Now we're in the old capital city of Bangkok. After hiking around the mountains, its nice to have accommodation with electricity and a shower to have a goo rest! Our trip to ChiangRai was long and tiring. From there, we took a bus to a small village in the mountains, where we met some hill tribe(部落)people who live a simple life-no electricity or telephones. They are the kindest, friendliest people I've ever met. Everyone smiles and says “hello”.Message 4: April 6thHi everybody,I would love to stay here longer, but we're both ready for the beach. Tomorrow we’ll take the train back to the south, and then we’re going to Phuket( 普吉)Island. It has several beaches, and it's famous for seashells. Thailand is an amazing country. with so many different things –big moderm cities and small traditional towns, mountains, forests and the seashore. Three weeks here Just isn't enough.44.Arriving at Thailand, the writer just wanted to enjoy first in the city.A. the sightsB. the sunshineC. the foodD. the hotel45.The word “acommodation" in Mesage 3 probably means .A. a marketB. a hotelC. a villageD.a restaurant46.The writer didn't see according to the messages.A. the seaB. mountainsC. Buddha statusD. deserts47.Which of the following can be the missing part in Message 4?A.Bangkok is really a wonderful city with lots to see.B.I am looking forward to coming to Thailand again.C.How I love the food in Chiengmai!D.Chiang Rai is a small place with beautiful s ceneries.CHaving a lovely pet can unquestionably make one's home life better-and in fact,it can make a difference to pet owners professional lives as well. In fact, according to a new survey, people who have owned pets may be more professionally successful and this is good news for pet parents who want to be successful and powerful.How exactly doe s pet o w ner s hip cau s e caree(r职业生涯)s ucce ss?The re s earcher s surveyed 857 adults in the United States with different kinds of careers. Well, according to the research, some successful people reported that their pet helped teach them lessons like responsibility, creativity,empathy(同情心),di s cipline(纪律)and organization,w hich have all been valuable in the bu s ine ss world.What about people who grew up without pets, but have adopted ( 领养)pets as adults? Luckily for those, the survey showed that present pet ownership can also help with professional success.According to the research, 86 percent of pet parents surveyed said owning pets help them stick to a normal order in their lives, better manage their time, and more tasks without wasting time or money, but even if you don't think your pet has direetly helped you, your workmates’knowledge that you have a pet may actually be beneficial for your career. In fact 80 percent of people surveyed said they feel more connected to workmates who are pet owners, and 79 percent of those surveyed believe that workmates who have pets are more hard-working.48.In which part of a newspaper can you read the passage?A. News.B. Advertisement.C. LettersD. Life &Fun.49.Having a pet helps people according to the last paragraph.A. run faster and exercise moreB. better manage their timeC. have a balance dietD. sleep easily and well50.What is the main idea of the passage?A.People who have pets may be more successful.B.People prefer to dogs rather than cats.C.People who have pets may be happier.D.People who do not have pets may be unlucky51.What will the writer talk about if there is another paragraph?A. The places to get a pet.B. An introduction to pets.C. A successful example of a pet owner.D. Differences between dogs and catsDFrom the Forbidden City to the Great Wall, ancient Chinese people have always been praised for their building skills and wisdom. And their great skills have been passed down to modern Chinese people. You can see this in recent buildings, such as the National Stadium, also known as the"Bird's Nest” in Beijing, and the Shanghai Tower. And recently, China has shown even more great building skills. On Oct 23, 2018, President Xi Jinping announced(宣布)the opening of the Hong Kong-Zhuhai-Macao Bridge(HZMB) at an opening ceremony in Zhuhai, Guangdong p rovince.The HZMB, which is located at( 位于) the waters of the Lingdingyang of Zhujiang River, is a huge sea crossing, connecting Hong Kong, Zhuhai and Macao.As the world's longest sea-based project, the 55-kilometre bridge is the result of five years of research and another nine years of building. It has been named as one of the “seven wonders of the modern w orld” by The G uardian.(卫报)The project is made up of a 22.9-kilometer-long main bridge, a 6.7-kilometer- long tunnel and an man-made island off the bridge. It is designed with a service life of 120 years. It can withstand (抵御) a magnitude-8 earthquake."Meanwhile, the Y-shaped bridge could reduce travel time from Hong Kong to Zhuhai and Macao from four hours to about 45 minutes."The bridge will not only be a transport connection. It will be a social, economic(经济), cultural, and tourism connection among the three areas, "Yu Lie, deputy director of the HK-Zhuhai-Macao Bridge Authority, told Xinhua.It will bring people in Hong Kong, Macao and Guangdong within a"one- hour living circle", which is expected to attract more visitors to the Guangdong-Hong Kong-Macao Greater Bay Area. Indeed, the HZMB is one of the most important elements(元素) of the development of the Bay Area.52.The opening of the HZMB was held in .A. Hong KongB. ZhuhaiC.MacaoD.Beijing53.It took the team years to build the HZMB.A.sevenB. fiveC. nineD.fourteen54.Which is of the following is TRUE according to the passage?A.The HZMB has been named as the seventh wonder of the modern world.B.People began to build the HZMB in the year 2010.C.The HZMB can be used for more than 120 years.D.If you travel across the HZMB from Hong Kong to Zhuhai and Macao, it will take only45 ninutes.55.The writer wrote the passage to .A. introduce the HZMBB. show how important the HZMB isC. attract tourists to visit the HZMBD. ask people to leam from the buildersEThe Chinese sci- fi movie The Wondering Earth makes people excited. How about scary movies? Whenever we watch a scary movie and something scary happens, we might close our eyes andscream. However, chances are that we'll continue to watch and enjoy the movie anyway. So why can fear be so much fun?A recent study made by researchers at the University of Pittsburgh in the US shows that watching scary movies can raise our mood, help make people together and make us confident. In the study, 262 adults were asked to enter a haunted house attraction. Inside, they had to stay there for 35 minutes, and were asked to record(记录) their feelings both before and after the expericnce. At the same time, the researchers also watched their brain waves.According to the researchers, people who took part in the research were more likely to be happier and less worried and tired after they left the attraction. That's because in this intense(紧张的)condition, their brai ns gave out more dopamine(多巴胺),a chemical w hich “produce s a feeling ot being happy that continues after the threat(威胁) has passes" reported Business Insider.What's more, this feeling may bring people together. According to The Conversation, experiencing the attraction is just like "running a 5 kilometer race or climbing up a difficult climbing wall." This means that people in scary situations are more likely to be uncertain and depend on others for support.Being scared in a safe place is a source( 来源)of enjoyment and makes us feel good physically and can even make us feel confident by reminding us that we can make it through a scary situation,we are strong, "researchers told The Independent.56.This passage mainly talks about the feeling of .A. fearB. confidenceC. happinessD.success57.Which of the following is NOT TRUE about Dopamine in the third paragraph?A.It is a chemical that comes from people's brains.B.It makes people happy when they're in intense.C.It makes people happier after the threat has passed.D.The brains don't give it out when people feel happy.58.It can be inferred (推断) from the passage that .A.Sci- fi movies are better than scary m ovies because they make people excited.B.Watching scary movies may help people make friends.C.Dopamine is a chemical that produces a feeling of happiness.D.The more movies you watch the stronger you will be.59.If we put the passage into three parts, which of the following is the best?(①=para.(自然段)1 ②=para.2 ③=P ara.3 ④=P ara.4 ⑤=P ara.5)V.口语运用。