第15周末练习题oc
北师大版七年级数学上册章节同步练习题（全册-共57页）
北师⼤版七年级数学上册章节同步练习题（全册-共57页）北师⼤版七年级数学上册章节同步练习题（全册，共57页）⽬录第⼀章丰富的图形世界1 ⽣活中的⽴体图形2 展开与折叠3 截⼀个⼏何体4 从三个⽅向看物体的形状单元测验第⼆章有理数及其运算1 有理数2 数轴3 绝对值4 有理数的加法5 有理数的减法6 有理数加减混合运算7 有理数的乘法 8 有理数的除法9 有理数的乘⽅ 10 科学记数法11 有理数的混合运算 12 ⽤计算器进⾏运算单元测验第三章整式及其加减1 字母表⽰数2 代数式3 整式4 整式的加减5 探索与表达规律单元测验第四章基本平⾯图形1 线段射线直线2 ⽐较线段的长短3 ⾓ 4⾓的⽐较5 多边形和圆的初步认识单元测验第五章⼀元⼀次⽅程1 认识⼀元⼀次⽅程2 求解⼀元⼀次⽅程3 应⽤⼀元⼀次⽅程——⽔箱变⾼了4 应⽤⼀元⼀次⽅程——打折销售5 应⽤⼀元⼀次⽅程——“希望⼯程”义演6 应⽤⼀元⼀次⽅程——追赶⼩明单元测验第六章数据的收集与整理1 数据的收集2 普查和抽样调查3 数据的表⽰4 统计图的选择第⼀章丰富的图形世界1．1⽣活中的⽴体图形（1）基础题：1．如下图中为棱柱的是（）2．⼀个⼏何体的侧⾯是由若⼲个长⽅形组成的，则这个⼏何体是（）A．棱柱 B．圆柱 C．棱锥 D．圆锥3．下列说法错误的是（）A．长⽅体、正⽅体都是棱柱 B．三棱柱的侧⾯是三⾓形C．直六棱柱有六个侧⾯、侧⾯为矩形 D．球体和圆是不同的图形4．数学课本类似于，⾦字塔类似于，西⽠类似于，⽇光灯管类似于。
5．⼋棱柱有个⾯，个顶点，条棱。
6．⼀个漏⽃可以看做是由⼀个________和⼀个________组成的。
7．如图是⼀个正六棱柱，它的底⾯边长是3cm，⾼是5cm．（1）这个棱柱共有个⾯，它的侧⾯积是。
（2）这个棱柱共有条棱，所有棱的长度是。
提⾼题：⼀只⼩蚂蚁从如图所⽰的正⽅体的顶点A沿着棱爬向有蜜糖的点B，它只能经过三条棱，请你数⼀数，⼩蚂蚁有种爬⾏路线。
中考英语第十五周阅读周周练（A、B卷）
中考英语第十五周阅读周周练（A、B卷）阅读周周练一、完形填空。
通读下面短文，从A、B、C三个选项中选出可以填入空白处的正确答案。
The way a person feels inside is important. It can be really hard not to tell 1 that you’re feeling sad, worried, or upset. Then, it’s just you and these 2 feelings. If you keep feelings locked inside, it can even 3 you feel sick!But if you talk with someone who 4 you, like your mom or dad, you will almost always start to 5 better. Now you’re not all alone with your pro blems or worries. It doesn’t 6 your problems and worries magically (神奇地) get lost, but at least someone else knows 7 trouble with you is and can help you how to deal with it.Your mom and dad want to know if you have 8 because they love you and they want t o know what’s happening in your 9 . But what if a kid doesn’t want to talk with mom or dad? Then find another trusted adult, 10 a relative or a friend at school. Maybe this person can help you talk with your mom and dad about your problem or worries.( ) 1. A. someone B. somebody C. anyone( ) 2. A. bad B. happy C. pleasure( ) 3. A. keep B. make C. take( ) 4. A. looks for B. asks for C. cares for( ) 5. A. feel B. sound C. smell( ) 6. A. matter B. mean C. think( ) 7. A. when B. why C. what( ) 8. A. problems B. money C. clothes( ) 9. A. school B. family C. life( ) 10.A. as B. like C. for二、阅读理解。
四年级英语月份词汇练习题30题
四年级英语月份词汇练习题30题1. J___uary is the first month of the year.A.auB.ouC.iu答案解析：A。
January 的正确拼写是J 开头，后面是au，然后是nuary。
选项B 和C 都不能组成正确的单词。
2. F___bruary has 28 or 29 days.A.eaB.eeC.ei答案解析：A。
February 的正确拼写是F 开头，后面是ea，然后是bruary。
选项B 和C 都不能组成正确的单词。
3. Ma___h is the third month of the year.A.ycB.rcC.yh答案解析：A。
March 的正确拼写是Ma 开头，后面是rch，但这里需要补全的是中间部分，是y。
选项B 和C 都不能组成正确的单词。
4. Ap___il is a month with beautiful flowers.A.roB.riC.re答案解析：B。
April 的正确拼写是Ap 开头，后面是ril。
选项A 和C 都不能组成正确的单词。
5. Ju___e is a month of summer vacation.A.liB.ne答案解析：B。
June 的正确拼写是Ju 开头，后面是ne。
选项 A 和C 都不能组成正确的单词。
6. Jul___ is a hot month.A.yiB.yuC.ay答案解析：C。
July 的正确拼写是Jul 开头，后面是y，但这里需要补全的是后面部分，是ay。
选项 A 和B 都不能组成正确的单词。
7. Au___ust is a month for traveling.A.uyB.iuC.gu答案解析：C。
August 的正确拼写是Au 开头，后面是gust，但这里需要补全的是中间部分，是gu。
选项 A 和B 都不能组成正确的单词。
8. Se___tember is the start of a new school term.A.peB.poC.re答案解析：A。
七年级下第15周周末作业
一、选择题（每小题3分，共36分）1.下列事件中属于随机事件的是（）A.抛出的篮球会落下B.有黑球，白球的袋里摸出红球C.367人中有2人时同月同日出生D.买1张彩票，中500万大奖2.从一副扑克牌中抽出4张红桃、3张梅花、2张黑桃放在一起洗匀，从中一次抽出8张牌，恰好有红桃、梅花、黑桃三种牌都被抽到，这个事件是（）A.必然事件B.随机事件C.不可能事件D.以上都不对3.下列事件是确定事件的是（）A.阴天一定会下雨B.黑暗中从5把不同的钥匙中随意摸出一把，用它打开了门C.打开电视机，任选一个频道，屏幕上正在播放新闻联播D.在学校操场上向上抛出的篮球一定会下落4.下列图形中，不是轴对称图形的是（）A. B. C. D.5.平行四边形、矩形、菱形、等腰三角形、正方形中时轴对称图形的有（）个。
A.1B.2C.3D.46.将一正方形纸片按下面图（1）、（2）的方式依次对折后，再沿（3）中的虚线裁剪，最后将（4）中的纸片打开铺平，所得图案应该是下面图案中的（）A. B. C. D.7.下列各时刻是轴对称图形的为（）A. 12:21B.13:08C.12:50D.10:508.如图，直线l表示石家庄的太平河，点P表示朱河村，点Q表示黄庄村，欲在太平河l上修建一个水泵站（记为点M），分别向两村供水，现有如下四种修建水泵站供水管道的方案，图中实线表示修建的管道，则修建的管道最短的方案是（）A. B. C. D.9.下列语句中正确的个数有（）①角的对称轴是角的平分线；②两个能全等的图形一定能关于某条直线对称；③一个轴对称图形不一定只有一条对称轴；④两个成轴对称的图形的对应点一定在对称轴的两侧A.1B.2C.3D.410.如图，将△ABC 沿直线DE 折叠后，使得点B 与点A 重合。
已知AC=5cm ，△ADC 的周长为17cm ，则BC 的长（ ）A.7cmB.10cmC.12cmD.22cm11.如图，已知∠AOB ，按照以下步骤画图：（1）以O 为圆心，适当长为半径画弧，交OA 于点M ，交OB 与点N ，（2）分别以点M 、N 为圆心，大于21MN 的长半径画弧，两弧在∠AOB 内部相交于点C ，（3）作射线OC ，则判断△OMC ≌△ONC 的依据是（ ）A.边边边B.边角边C.角边角D.角角边第10题图 第11题图12.在一个不透明的口袋中，装有3个红球，2个白球，除颜色不同外其余都相同，则随机从口袋中摸出一个球为红色的概率是（ ） A.31 B.52 C.51 D.53二、填空题（每小题3分，共12分）13.某公路急转弯处设立了一面圆型大镜子，从镜子中看到汽车车的部分号码如图所示，则该车牌照的部分号码为______________。
(七年级英语)第15周周末作业(基础)
七下Unit 10 周末作业（基础）Class ___________ Number ___________ Name_____________一．单项选择( )1. There is____ onion and ____ meat.A.a; someB. an; someC. a; anyD. an; any( )2. ---Would you like something to eat?---_______. I’m not hungry.A. Yes, I’d like t oB. Yes, I wouldC. No, thanksD. Yes, please( )3. There are some noodles. You can’t _________.A.cut them upB.cut it up B.cut it up D.cuts up them( )4. He is too hungry and he wants two _______.A. bowl of noodlesB.bowls of noodlesC.bowls of noodleD.bowl of noodle( )5. ---What _______ would you like? ---A medium one.A. sizeB. kindC. colorD. kind of( )6. ---Let’s do something at the party. What about singing ?---No, I’d like _______.A.to danceB. dancingC.danceD.dances( )7.___ there ____ mutton in the beef soup?A.Are; someB.Are; anyC.Is; someD.Is; any( )8. ---Would you like green tea ____ juice?---I don’t like green tea ____ juice.A.and; andB.or; orC. and; orD. or; and( )9.I often eat some _______ and _______ on Sunday evenings.A. tomatoes; fishB.tomato; fishC.tomatoes; fishesD. tomato; fishes( )10.Are there any _______ in the _______ soup?A. vegetable; potatoesB. vegetables; potatoesC. vegetable; potatoD. vegetables; potato( )11. He’d like me to help him_________ English.A. learntB. learningC. learnD. learns( )12.Today’s Tom’s birthday. He blows out all the candles ____ one go.A.inB.onC.atD.for( )13.The number of candles_____ the person’s age.A.isB.areC.beD./( )14.Long noodles ____ good luck ___ people.A.bring; forB.take; toC.take; forD.bring;to( )15. ---_______? ---I’d like a cup of tea.A. Would you like some teaB. What would you likeC. Do you like teaD. What size would you like二、完形填空Bill is a lazy boy. He doesn’t have good 1.He doesn’t like to get up early. In the morning, he 2 at seven and brushes his teeth. Then he goes to school at seven fifteen. He doesn’t have much time for breakfast, so he usually eats very 3.For lunch, he usually eats hamburgers and ice cream.He knows they are not 4for him, but they taste good. He doesn’t like vegetables. After 5, he sometimes reads some storybooks. For dinner, he usually eats much 6like beef and chicken at home. After dinner, he often 7the dirty dishes in the kitchen and doesn’t wash them. Then he either watches basketball games on 8or plays computer games. He even eats some candies before he goes to bed. They are bad for his 9.So he is not 10and has to see the doctor every month. Can you help him?( ) 1. A.vacations B.habits C.uniforms D.friends( ) 2. A.puts up B.puts out C.gets up D.gets out( ) 3. A.quickly B.slowly C.loudly D.hard( ) 4 A.good B.bad C.right C.right( ) 5. A.breakfast B.lunch C.dinner D.school( ) 6. A.vegetables B.meat C.fruit D.drinks( ) 7. A.gives B.makes C.leaves D.washes( ) 8. B.the radio C.the phone D.paper( ) 9. A.head B.mouth C.face D.teeth( ) 10. A.healthy B.hungry C.heavy D.handsome三、语法选择I have a lot of teachers now and I love them all, 1 I think I love my English teacher, Amy, best.Amy comes from 2. _UK. But she loves Chongqing very much. She thinks Chongqing is a wonderful city. She loves Chongqing food. Do you know what she likes for breakfast? Bread and milk? No, she doesn’t. She only has some noodles. Hot pot is 3 favorite and she always eats it on Saturday and Sunday. Amy has a daughter and a son. Her 4 name is May. Her son’s name is Jack. They are 5 . They go to the same school. They like hot pot, too. They are all in Chongqing now.We have English 6 Monday to Friday. So Amy is very 7 . But she is always nice and happy. All my classmates like her and her classes very much. She often plays English games and 8 English songs with us. When we have questions, we enjoy 9 her for help.Now I think I can do well in English because I have 10 English teacher, Amy.( ) 1. A. so B. and C. or D. but( ) 2. A. a B. an C. the D. /( ) 3. A. her B. she C. herself D. hers( ) 4. A. daughter B. daughters’ C. daughters D. daughter’s( ) 5. A. 11-year-old B. 11 years old C. 11-years-old D. 11 year old( ) 6. A. from B. on C. by D. in( ) 7. A. busier B. busiest C. the busiest D. busy( ) 8. A. sing B. singing C. sings D. sang( ) 9. A. ask B. to ask C. asking D. asks( ) 10. A. good B. the best C. best D. better四短文填空A good meal can give us energy. As students, we should eat something to 1.________healthy. Let me2._you something about my three meals.3.breakfast, I like milk and bread. For4., I have rice, chicken and vegetables. But I5.like fish. For dinner, I eat noodles and soup. I will eat an ice cream at dinner.6.is sweet and delicious. My favorite 7______. is the apple. I don’t like eating junk food 8.it is not 9. for us. I don’t want to 10.fat.1. ___________2. ___________3. ___________4. ___________5. ___________6. ___________7. ___________8. ___________9. ___________ 10. ___________。
2022-2023学年苏科版九年级数学上册 《圆周角》同步练习题(含答案)
2022-2023学年苏科版九年级数学上册《2.4圆周角》同步练习题（附答案）一．选择题1．如图，四边形ABCD是⊙O的内接四边形，连接AO、OC，∠ABC＝70°，AO∥CD，则∠OCD的度数为（）A．40°B．50°C．60°D．70°2．如图，AB为⊙O的直径，C为⊙O上一点，其中AB＝4，∠AOC＝120°，P为⊙O上的动点，连接AP，取AP中点Q，连接CQ，则线段CQ的最大值为（）A．3B．1+C．1+3D．1+3．如图，点A、B分别在x轴、y轴上（OA＞OB），以AB为直径的圆经过原点O，C是的中点，连结AC，BC．下列结论：①∠ACB＝90°；②AC＝BC；③若OA＝4，OB＝2，则△ABC的面积等于5；④若OA﹣OB＝4，则点C的坐标是（2，﹣2）．其中正确的结论有（）A．4个B．3个C．2个D．1个4．如图，AB是半圆O的直径，将半圆沿弦BC折叠，折叠后的圆弧与AB交于点D，再将弧BD沿AB对折后交弦BC于E，若E恰好是BC的中点，则BC：AB＝（）A．B．C．D．5．如图，在△ABC中，∠ACB＝90°，AC＝8，BC＝6，P是AC上的一点，PH⊥AB于点H，以PH为直径作⊙O，当CH与PB的交点落在⊙O上时，AP的值为（）A．3B．4C．5D．66．如图，AB是⊙O的直径，C是⊙O上的一点，CD平分∠ACB交⊙O于点D，交AB于点E，若AC＝6，BC＝8，则的值为（）A．B．1C．D．7．如图，四边形ABCD内接于⊙O，AB是⊙O的直径，AD＝DC，分别延长BA、CD，交点为E，作BF⊥EC，并与EC的延长线交于点F．若AE＝AO，BC＝6，则CF的长为（）A．B．C．D．二．填空题8．如图，⊙O的半径为，四边形ABCD为⊙O的内接矩形，AD＝6，M为DC中点，E为⊙O上的一个动点，连结DE，作DF⊥DE交射线EA于F，连结MF，则MF的最大值为．9．如图，正方形ABCD的边长是4，F点是BC边的中点，点H是CD边上的一个动点，以CH为直径作⊙O，连接HF交⊙O于E点，连接DE，则线段DE的最小值为．10．如图，点D为边长是4的等边△ABC边AB左侧一动点，不与点A，B重合的动点D 在运动过程中始终保持∠ADB＝120°不变，则四边形ADBC的面积S的最大值是．11．如图，在Rt△ABC中，已知∠A＝90°，AB＝6，BC＝10，D是线段BC上的一点，以C为圆心，CD为半径的半圆交AC边于点E，交BC的延长线于点F，射线BE交于点G，则BE•EG的最大值为．三．解答题12．如图，A，P，B，C是⊙O上的四个点，∠APC＝∠CPB＝60°．（1）判断△ABC的形状，并证明你的结论．（2）证明：P A+PB＝PC．13．如图，在△ABC中，AB＝AC，以AB为直径的圆交AC于点D，交BC于点E，延长AE至点F，使EF＝AE，连接FB，FC．（1）求证：四边形ABFC是菱形；（2）若AD＝7，BE＝2，求半圆和菱形ABFC的面积．14．如图，AB是⊙O的直径，弦CD⊥AB于点E，G是劣弧上一点，AG，DC的延长线交于点F．（1）求证：∠FGC＝∠AGD．（2）若G是的中点，CE＝CF＝2，求GF的长．15．已知⊙O的直径为10，点A、点B、点C在⊙O上，∠CAB的平分线交⊙O于点D．（1）如图①，若BC为⊙O的直径，AB＝6，求AC、BD、CD的长；（2）如图②，若∠CAB＝60°，求BD的长．16．如图，已知圆O，弦AB、CD相交于点M．（1）求证：AM•MB＝CM•MD；（2）若M为CD中点，且圆O的半径为3，OM＝2，求AM•MB的值．17．如图，AB是⊙O的直径，点C在圆上，∠BAD是△ABC的一个外角，它的平分线交⊙O 于点E．不使用圆规，请你仅用一把不带刻度的直尺作出∠BAC的平分线．并说明理由．18．如图，AB为⊙O的直径，点C在⊙O上，延长BC至点D，使DC＝CB，延长DA与⊙O的另一个交点为E，连接AC，CE．（1）求证：∠B＝∠D；（2）若AB＝4，BC﹣AC＝2，求CE的长．19．已知⊙O的直径AB与弦CD垂直相交于点E．取上一点H，连CH，与AB相交于点F，连接BC．（1）如图1，连接AH，作AG⊥CH于G，求证：∠HAG＝∠BCE；（2）如图2，若H为的中点，且HD＝3，求HF的长．20．如图，在△ACE中，AC＝CE，⊙O经过点A，C且与边AE，CE分别交于点D，F，点B是上一点，且，连接AB，BC，CD．（1）求证：△CDE≌△ABC；（2）若AC为⊙O的直径，填空：①当∠E＝时，四边形OCFD为菱形；②当∠E＝时，四边形ABCD为正方形．21．如图，四边形ABCD内接于⊙O，AC为直径，AC和BD交于点E，AB＝BC．（1）求∠ADB的度数；（2）过B作AD的平行线，交AC于F，试判断线段EA，CF，EF之间满足的等量关系，并说明理由．22．如图，AB是⊙O的直径，C是的中点，CE⊥AB于E，BD交CE于点F，（1）求证：CF＝BF；（2）若CD＝12，AC＝16，求⊙O的半径和CE的长．23．如图，点A、B、C在⊙O上，用无刻度的直尺画图．（1）在图①中，画一个与∠B互补的圆周角；（2）在图②中，画一个与∠B互余的圆周角．24．如图，AB是⊙O的直径，AB＝10，弦CD与AB相交于点N，∠ANC＝30°，ON：AN ＝2：3，OM⊥CD，垂足为M．（1）求OM的长；（2）求弦CD的长．25．如图，四边形ABCD内接于⊙O，AC平分∠BAD，延长DC交AB的延长线于点E．（1）若∠ADC＝86°，求∠CBE的度数；（2）若AC＝EC，求证：AD＝BE．参考答案一．选择题1．解：∵∠ABC＝70°，∴∠AOC＝2∠ABC＝140°，∵AO∥CD，∴∠AOC+∠OCD＝180°，∴∠COD＝40°．故选：A．2．解：如图，连接OQ，作CH⊥AB于H．∵AQ＝QP，∴OQ⊥P A，∴∠AQO＝90°，∴点Q的运动轨迹为以AO为直径的⊙K，连接CK，当点Q在CK的延长线上时，CQ的值最大（也可以通过CQ≤QK+CK求解）在Rt△OCH中，∵∠COH＝60°，OC＝2，∴OH＝OC＝1，CH＝，在Rt△CKH中，CK＝＝，∴CQ的最大值为1+，故选：D．3．解：∵AB是直径，∴∠ACB＝90°，故①符合题意；∵C是中点，∴AC＝BC，故②符合题意；∵AB2＝OB2+OA2＝22+42，∴AB＝2，∵△ACB是等腰直角三角形，∴AC＝BC＝AB＝，∴△ACB的面积为＝5，故③符合题意；作CD⊥x轴于D，CE⊥y轴于E，∴∠ADC＝∠BEC＝90°，∵∠BCE+∠BCD＝∠ACD+∠BCD＝90°，∴∠BCE＝∠ACD，∵AC＝BC，∴△ACD≈△BCE，∴CD＝CE，AD＝BE，∴OECD是正方形，设正方形的边长为a，∴OA﹣a＝OB+a，∴2a＝OA﹣OB＝4，∴a＝2，∴点C坐标为：（2，﹣2），故④符合题意，故选：A．4．解：过D点作BC的垂线，垂足为M，延长DM交于D′，连接CD、DE、BD′，过点C作CF⊥AB于点F，如图所示：由等圆中圆周角相等所对的弧相等得：＝＝＝，∴AC＝CD＝DE，∴CM＝EM，∵E是BC的中点，∴CM＝BC，∵AB是半圆O的直径，∴AC⊥BC，∵DM⊥BC，∴DM∥AC，∴AD＝AB，设∠ABC＝α，则∠ACF＝α，∵AC＝CD，∴AD＝2AF，∴＝，∴AB＝2AC，BC＝＝AC，∴＝＝，∴BC：AB＝；故选：B．5．解：如图所示，当CH与PB的交点D落在⊙O上时，∵HP是直径，∴∠HDP＝90°，∴BP⊥HC，∴∠HDP＝∠BDH＝90°，又∵∠PHD+∠BHD＝90°，∠BHD+∠HBD＝90°，∴∠PHD＝∠HBD，∴HD2＝PD•BD，同理可证CD2＝PD•BD，∴HD＝CD，∴BD垂直平分CH，∴BH＝BC＝3，在Rt△ACB中，AB＝＝＝10，∴AH＝10﹣6＝4，∵∠A＝∠A，∠AHP＝∠ACB＝90°，∴＝，∴AP＝5，故选：C．6．解：如图，过点E作EM⊥BC于M，EN⊥AC于N，过点D作DH⊥BC于H，DG⊥CA 交CA的延长线于G．∴AB是直径，∴∠ACB＝90°，∵CD平分∠ACD，∴＝，∴AD＝BD，∵EM⊥BC，EN⊥AC，DH⊥BC，DG⊥AC，∴EM＝EN，DH＝DH，∵•AC•BC＝•AC•EN+•BC•EM，∴EM＝EN＝，∵∠ECN＝∠CEN＝45°，∴CN＝EN＝，∴EC＝，∵∠AGD＝∠DHB＝90°，AD＝BD，DG＝DH，∴Rt△DGA≌Rt△DHB（HL），∴AG＝BH，同法可证，Rt△CGD≌Rt△CHB（HL），∴CG＝CH，∴AC+BC＝CG﹣AG+CH+BH＝2CG＝14，∴CG＝DG＝7，∴CD＝7，∴DE＝7﹣＝，∴＝＝．7．解：如图，连接AC，BD，OD，∵AB是⊙O的直径，∴∠BCA＝∠BDA＝90°．∵BF⊥EC，∴∠BFC＝90°，∵四边形ABCD是⊙O的内接四边形，∴∠BCF＝∠BAD，∵OD是⊙O的半径，AD＝CD，∴OD垂直平分AC，∴OD∥BC，∴＝，而AE＝AO，即OE＝2OB，BE＝3OB，BC＝6∴＝＝＝，＝2，∴OD＝4，CE＝DE，又∵∠EDA＝∠EBC，∠E公共角，∴DE•DE＝4×12，∴DE＝4，∴CD＝2，则AD＝2，∴＝，∴CF＝．故选：A．二．填空题8．解：如图，连接AC交BD于点O，以AD为边向上作等边△ADJ，连接JF，JA，JD，JM．∵四边形ABCD是矩形，∴∠ADC＝90°，∵AD＝6，AC＝4，∴sin∠ACD＝＝，∴∠ACD＝60°，∴∠FED＝∠ACD＝60°，∵DF⊥DE，∴∠EDF＝90°，∴∠EFD＝30°，∵△JAD是等边三角形，∴∠AJD＝60°，∴∠AFD＝∠AJD，∴点F的运动轨迹是以J为圆心JA为半径的圆，∴当点F在MJ的延长线上时，FM的值最大，此时FJ＝6，JM＝＝，∴FM的最大值为6+，故答案为：6+．9．解：连接CE，∵CH是⊙O的直径，∴∠CEH＝90°，∴∠CEF＝180°﹣90°＝90°，∴点E在以CF为直径的⊙M上，连接EM、DM，∵正方形ABCD的边长是4，F点是BC边的中点，∴BC＝CD＝4，∠BCD＝90°，CF＝BC＝2，∴FM＝MC＝EM＝1，在Rt△DMC中，DM＝＝＝，∵DE≥DM﹣EM，∴当且仅当D、E、M三点共线时，线段DE取得最小值，∴线段DE的最小值为﹣1，故答案为：﹣1．10．解：∵△ABC是等边三角形，∴AB＝AC＝BC＝4，∠ACB＝∠ABC＝∠BAC＝60°，∵∠ADB＝120°，∴∠ADB+∠ACB＝180°，∴四边形ACBD是圆内接四边形，∴OA＝OB＝AB＝＝4，∴⊙O直径为8．如图，作四边形ACBD的外接圆⊙O，将△ADC绕点C逆时针旋转60°，得到△BHC，∴CD＝CH，∠DAC＝∠HBC，∵四边形ACBD是圆内接四边形，∴∠DAC+∠DBC＝180°，∴∠DBC+∠HBC＝180°，∴点D，点B，点H三点共线，∵DC＝CH，∠CDH＝60°，∴△DCH是等边三角形，∵四边形ADBC的面积S＝S△ADC+S△BDC＝S△CDH＝CD2，∴当CD最大时，四边形ADBC的面积最大，∴当CD为⊙O的直径时，CD的值最大，即CD＝8，∴四边形ADBC的面积的最大值为CD2＝16，故答案为：16．11．解：如图，过点C作CH⊥EG于点H．∵CH⊥EG，∴EH＝GH，∵∠A＝∠CHE＝90°，∠AEB＝∠CEH，∴BE•EH＝AE•EC，∴BE•2EH＝2•AE•EC，∴EB•EG＝2AE•EC，设EC＝x，在Rt△ABC中，AC＝＝＝8，∴EB•EG＝2x•（8﹣x）＝﹣2（x﹣4）2+32，∵﹣2＜0，∴x＝4时，BE•EG的值最大，最大值为32，故答案为：32．三．解答题12．（1）解：△ABC是等边三角形，理由如下：由圆周角定理得，∠ABC＝∠APC＝60°，∠BAC＝∠CPB＝60°，∴△ABC是等边三角形；（2）证明：在PC上截取PH＝P A，∵∠APC＝60°，∴△APH为等边三角形，∴AP＝AH，∠AHP＝60°，在△APB和△AHC中，，∴△APB≌△AHC（AAS）∴PB＝HC，∴PC＝PH+HC＝P A+PB．13．（1）证明：∵AB是直径，∴∠AEB＝90°，∴AE⊥BC，∵AB＝AC，∴BE＝CE，∵AE＝EF，∴四边形ABFC是平行四边形，∵AC＝AB，∴四边形ABFC是菱形．（2）设CD＝x．连接BD．∵AB是直径，∴∠ADB＝∠BDC＝90°，∴AB2﹣AD2＝CB2﹣CD2，∴（7+x）2﹣72＝42﹣x2，解得x＝1或﹣8（舍弃）∴AC＝8，BD＝＝，∴S菱形ABFC＝8．∴S半圆＝•π•42＝8π．14．（1）证明：如图1，连接AC，∵AB是⊙O的直径，弦CD⊥AB，∴＝，∴AD＝AC，∴∠ADC＝∠ACD，∵点A、D、C、G在⊙O上，∴∠FGC＝∠ADC，∵∠AGD＝∠ACD，∴∠FGC＝∠AGD；（2）解：如图，过点G作GH⊥DF于点H．∵∠DAG+∠DCG＝180°，∠DCG+∠FCG＝180°，∴∠DAC＝∠FCG，∵＝，∴AG＝CG，∵∠AGD＝∠FGC，∴△DAG≌△FCG（ASA），∴CF＝AD＝3，DG＝FG，∵GH⊥DF，∴DH＝FH，∵AB⊥CD，∴DE＝EC＝2，∴DF＝2+2+3＝7，∴DH＝HF＝3.5，∴AE＝＝＝，∴AF＝＝＝，∵GH∥AE，∴＝，∴＝，∴GF＝．15．解：（1）如图①，∵BC是⊙O的直径，∴∠CAB＝∠BDC＝90°．∵在直角△CAB中，BC＝10，AB＝6，∴由勾股定理得到：AC＝＝＝8．∵AD平分∠CAB，∴＝，∴CD＝BD．在直角△BDC中，BC＝10，CD2+BD2＝BC2，∴易求BD＝CD＝5；（2）如图②，连接OB，OD，∵AD平分∠CAB，且∠CAB＝60°，∴∠DAB＝∠CAB＝30°，∴∠DOB＝2∠DAB＝60°．又∵OB＝OD，∴△OBD是等边三角形，∴BD＝OB＝OD．∵⊙O的直径为10，则OB＝5，∴BD＝5．16．解：（1）∵∠A＝∠C，∠D＝∠B，∴，即AM•MB＝CM•MD．（2）连接OM、OC．∵M为CD中点，∴OM⊥CD在Rt△OMC中，∵OC＝3，OM＝2∴CM＝DM＝，由（1）知AM•MB＝CM•MD．∴AM•MB＝•＝5．17．解：作直径EF交⊙O于F，连接AF，则AF是∠BAC的平分线．理由是：∵EF是⊙O的直径，∴∠EAF＝90°，即∠EAO+∠OAF＝90°，∵AE平分∠BAD，∴∠DAE＝∠EAO，∴∠CAF＝∠OAF，∴AF是∠BAC的平分线．18．（1）证明：∵AB为⊙O的直径，∴∠ACB＝90°，∴AC⊥BC，又∵DC＝CB，∴AD＝AB，∴∠B＝∠D；（2）解：设BC＝x，则AC＝x﹣2，在Rt△ABC中，AC2+BC2＝AB2，∴（x﹣2）2+x2＝42，解得：x1＝1+，x2＝1﹣（舍去），∵∠B＝∠E，∠B＝∠D，∴∠D＝∠E，∴CD＝CE，∵CD＝CB，∴CE＝CB＝1+．19．（1）证明：如图1中，∵AB⊥CD，∴∠CEB＝90°，∵AG⊥CH，∴∠AGH＝90°，∵∠GAH+∠AHG＝90°，∠BCE+∠CBE＝90°，∠ABC＝∠AHG，∴∠HAG＝∠BCE．（2）解：如图2中，连接AC，AD，DF．∵AB⊥CD，∴CE＝DE，∴AC＝AD，FC＝FD，∴∠FCD＝∠FDC，∠ACD＝∠ADC，∴∠ACF＝∠ADF，∵＝，∴∠ADF＝∠DCH＝∠ADH，∴∠ACF＝∠DCF＝∠FDC＝∠ADF，∵∠HFD＝∠FCD+∠FDC＝2∠FCD，∠HDF＝2∠FCD，∴∠HDF＝∠HFD，∴FH＝DH＝3．20．证明：（1）∵，∴∠BAC＝∠DCE，∵∠CDE是圆内接四边形ABCD的外角，∴∠CDE＝∠ABC，在△CDE和△ABC中，，∴△CDE≌△ABC（AAS）；（2）如图，①连接AF，∵AC是直径，∴OA＝OC，∠ADC＝∠AFC＝90°，∵四边形OCFD是菱形，∴DF∥AC，OD∥CE，∵OA＝OC，∴AD＝DE（经过三角形一边的中点平行于一边的直线必平分第三边），∵DF∥AC，∴CF＝EF（经过三角形一边的中点平行于一边的直线必平分第三边），∵∠AFC＝90°，∴AC＝AE（垂直平分线上的点到两端点的距离相等），∵AC＝CE，∴AC＝AE＝CE，∴△ACE是等边三角形，∴∠E＝60°；故答案为：60°；②∵四边形ABCD是正方形，∴AD＝CD，∠ADC＝90°，∴∠ACD＝45°，∵AC＝CE，CD⊥AE，∴∠DCE＝∠ACD＝45°，∴∠ACE＝90°，∵AC＝CE，∴△ACE是等腰直角三角形．∴∠E＝45°．故答案为：45°．21．解：（1）如图1，∵AC为直径，∴∠ABC＝90°，∴∠ACB+∠BAC＝90°，∵AB＝BC，∴∠ACB＝∠BAC＝45°，∴∠ADB＝∠ACB＝45°；（2）线段EA，CF，EF之间满足的等量关系为：EA2+CF2＝EF2．理由如下：如图2，设∠ABE＝α，∠CBF＝β，∵AD∥BF，∴∠EBF＝∠ADB＝45°，又∠ABC＝90°，∴α+β＝45°，过B作BN⊥BE，使BN＝BE，连接NC，∵AB＝CB，∠ABE＝∠CBN，BE＝BN，∴△AEB≌△CNB（SAS），∴AE＝CN，∠BCN＝∠BAE＝45°，∴∠FCN＝90°．∵∠FBN＝α+β＝∠FBE，BE＝BN，BF＝BF，∴△BFE≌△BFN（SAS），∴EF＝FN，在Rt△NFC中，CF2+CN2＝NF2，∴EA2+CF2＝EF2；22．解：（1）证明：∵AB是⊙O的直径，∴∠ACB＝90°，又∵CE⊥AB，∴∠CEB＝90°，∴∠2＝90°﹣∠ABC＝∠A，又∵C是弧BD的中点，∴∠1＝∠A，∴∠1＝∠2，∴CF＝BF；（2）∵C是弧BD的中点，∴＝，∴BC＝CD＝12，又∵在Rt△ABC中，AC＝16，∴由勾股定理可得：AB＝20，∴⊙O的半径为10，∵S△ABC＝AC•BC＝AB•CE，∴CE＝＝9.6．23．解：（1）如图1，∠P即为所求：（2）如图2，∠CBQ即为所求．24．解：∵AB＝10，∴OA＝5，∵ON：AN＝2：3，∴ON＝2，∵∠ANC＝30°，∴∠ONM＝30°，∴OM＝ON＝1；（2）如图，连接OC，由勾股定理得：CM2＝CO2﹣OM2＝25﹣1＝24，∴CM＝2，∴CD＝2CM＝4．25．（1）解：∵四边形ABCD内接于⊙O，∴∠ADC+∠ABC＝180°，又∵∠ADC＝86°，∴∠ABC＝94°，∴∠CBE＝180°﹣94°＝86°；（2）证明：∵AC＝EC，∴∠E＝∠CAE，∵AC平分∠BAD，∴∠DAC＝∠CAB，∴∠DAC＝∠E，∵四边形ABCD内接于⊙O，∴∠ADC+∠ABC＝180°，又∵∠CBE+∠ABC＝180°，∴∠ADC＝∠CBE，在△ADC和△EBC中，，∴△ADC≌△EBC，∴AD＝BE．。
中考英语阅读周周练有答案Week15
第三部分能力验收 - WEEK FIFTEEN（2）一、阅读理解（共9小题；共18分）AA global survey has asked 6,204 children in 47 countries around the world about their hopes, dreams and fears. The worldwide "Small Voices, Big Dreams" report is from the children's charity Child Fund. It asked ten to twelve-year-olds six questions about the world and their future. It discovered that education, food and the environment are their biggest worries. A Child Fund spokesman said, "We're always surprised to see how much importance children put on education." He added that he was pleased children saw the link between education and a better future. "It shows the depth of maturity(成熟) of children, who clearly understand the connection between education and changing their worlds for the better."The children were asked the question, "If you were president or leader of your country, what would you do to improve the lives of children in your country?" Most said they would focus on education. The children also answered the question "What are you most afraid of?" Over 25 per cent of kids in developing countries said their greatest fear was dangerous animals and insects. The environment was also a big worry for the children. The report says, "Across the world, nearly half of children said they would either plant more trees, build more green spaces or decrease(减少) littering to help improve the planet." As for future careers(职业), almost 20 per cent of children want to be a professional athlete when they grow up.1. The survey has asked .A. 47 children in 6,204 countriesB. 2,406 children in 74 countriesC. 4,602 children in 147 countriesD. 6,204 children in 47 countries2. Over 25 per cent of kids in developing countries said their greatest fear was .A. flood, droughts and diseaseB. attacks from neighboring countriesC. not having a mobile phone or iPadD. dangerous animals and insects3. If they were president or leader of their country, most students would to improve the lives of children.A. develop economyB. protect environmentC. build schoolsD. build hospitals4. Almost 20 per cent of children want to be a when they grow up.A. professional athleteB. doctor or lawyerC. rock star or movie starD. leader of their countryBLast Sunday the elephant keeper at London Zoo, Jim Robson, was killed by one of the elephants he loved. This was terrible, and it could be a big problem for the future of London Zoo—and maybe for all of Britain's city zoos.London Zoo said that it would move its three elephants to a wild animal park outside London. Its director-general(总经理), Michael Dixon said, "We are sorry that the elephants are leaving; there have been elephants at London Zoo since 1831."One British newspaper said that though many small animals were very interesting,most people wanted to see big animals-and most of all elephants.London Zoo is not only losing its elephants. The tigers will also leave soon and most of the bears have already gone. Outside the elephant house at London Zoo, a woman called Carmen said she hoped the zoo could keep big animals. "This is the only way the young people can see animals without traveling to other countries." she said."Zoos are not very good places for animals, but they can help to well keep them. Children can also learn a lot about the animals when they visit zoos." A boy named Tom said.Another visitor, a man called Alan, was very angry. "If we send them back to the wild they will die. If you take away big animals, people will stop visiting London Zoo. It can survive(继续生存) at the moment, but it won't survive in the future."However, Mary Roseau, director of the Federation(联合会) of Zoos, believes that city zoos can survive without keeping large animals.5. Who was Jim Robson?A. A visitor.B. An elephant keeper.C. A driver.D. An elephant.6. London Zoo has kept elephants .A. since it was builtB. for about 100 yearsC. since 1831D. since last Sunday7. According to the passage, have already left the zoo.A. the elephantsB. the tigersC. the pandasD. most of the bears8. Who support the idea that moves the big animals out of the zoo?A. Carmen.B. Tom.C. Alan.D. Mary Roseau.9. According to Alan, if we send the big animals back to the wild they will .A. dieB. live betterC. be lostD. come back二、完形填空（共10小题；共15分）My mother often asked me, “What is the most important part of the body?” Through the yea rs I would guess at 10 I thought was the correct answer. When I was younger, I thought sound wasvery important to us as humans, so I said. “My 11 , Mommy.” She said, “No. Many people are deaf. But you 12 thinking about it and I will ask you again soon.”Then last year, my grandpa 13 . Everybody was hurt. Everybody was crying. My mom looked at me when it was our 14 to say our final goodbye to Grandpa. She asked me, “Do you know the most important body part yet, my dear?” I was shocked 15 she asked me this now. I always thought this was a game between her and me. She saw the confusion(迷惑) on my face and told me, “This 16 is very important. It shows that you have 17 lived your life.” I saw h er eyes well up with tears(跟泪). She said, “My dear, the most important body part is your shoulder.” I asked. “Is it because it holds up your head?”She replied, “No, it is because it can hold the head of a friend or loved one when they 18 . Everybody needs a shoulder to cry on sometimes in life, my dear. I only hope that you have enough love and 19 that you will have a shoulder to cry on when you need it.”10. A. if B. what C. that D. whether11. A. ears B. eyes C. body D. head12. A. feel B. stop C. keep D. forget13. A. worried B. visited C. died D. came14. A. need B. chance C. duty D. turn15. A. when B. unless C. before D. but16. A. experience B. answer C. problem D. question17. A. easily B. really C. carefully D. especially18. A. sleep B. think C. laugh D. cry19. A. visitors B. friends C. classmates D. teachers三、阅读理解（共9小题；共18分）AIt was two months before Christmas. Nine-year-old Almie Rose told her father and me that she wanted a new bike. Her Barbi bike was just too old, and it needed repairing as well.As Christmas came nearer, her dream for a bike seemed to disappear, for she didn't mention it again. We were busy buying some beautiful story books, a doll house, a holiday dress and toys. Then much to our surprise, on December 24, she said she really wanted a bike more than anything else.Now we didn't know what to do. It was just too late. We were busy with Christmas dinner and packing children's presents, parents' presents, a brother's present and friends' presents till midnight. So there was no time to take to buy the "right bike" for our little girl. Thinking that we were parents who would make their child unhappy, we felt ashamed and sad.Suddenly my husband had an idea. "What if I make a little bike out of clay(泥土) and write a note that she could trade in (交换) the model bike for a real one?" So he spent the next five hours carefully working with clay to make a small bike.On Christmas morning, we were so excited for Almie Rose to open the little box with the beautiful red and white clay bike and the note. She opened and read the note loudly. She looked at me and Ron and said, "So, does this mean I can trade in this bike for a real one?" Smiling, I said, "Yes." Almie Rose had tears in her eyes when she replied, "I would never trade in this beautiful bike that Daddy made me. I prefer to keep it rather than get a real bike." At that moment, we would have moved the God to buy her every bike on the earth.20. Why did Rose want a new bike on Christmas Day?A. Because she didn't have a bike.B. Because her bike was old.C. Because her bike was stolen.D. Because her bike was out of style.21. The underlined word "ashamed" means in Chinese.A. 兴奋的B. 不开心的C. 紧张的D. 内疚的22. Why didn't her parents buy her a bike?A. Because they didn't have enough money.B. Because they thought she didn't want it any more.C. Because they forgot to buy it.D. Because they got angry with her.23. What did the parents do at last?A. They bought her a new bike.B. They said sorry to her.C. They made a clay bike for her.D. They did nothing.24. From Rose's words in the last paragraph, we know that she .A. still wanted to get a real bikeB. didn't know the meaning of the noteC. preferred a real bike to the model oneD. was greatly moved by what her father had doneBOne day when some government officials were rebuilding a barn(谷仓), they found a mouse hole in a corner and used smoke to force the mice inside the hole to come out. A while later they indeed saw mice running out, one after another. Then, everyone thought that all the mice had escaped. But just as they began to clean up, they saw two mice squeezing(挤) out at the mouth of the hole. With some efforts, the mice finally got out. However, it was strange that after they came out of the hole, they did not run away immediately. Instead, one chased(追逐) after the other near the mouth of the hole. It seemed that one was trying to bite the tail of the other.Everyone was puzzled, so they stepped nearer to take a look. They realized that one of the mice was blind and could not see anything, and the other was trying to allow the blind mouse to bite on his tail so that he could pull the blind one with him to escape.After seeing what happened, everyone was speechless and lost in thought. During the meal time, the group of people sat down in a circle and started to chat about what happened to the two mice.One serious American official said, "I think the relationship between those two mice was that of king and guard." The others thought for a while and said, "That was why!" A smart French said, "I think the relationship between those two mice was that of husband and wife." Again the others thought for a while, and all felt it made sense. A Japanese said, "I think the relationship between those two mice was that of mother and son." Once again the others thought for a while, and felt this was more reasonable. So they expressed agreement another time. At that moment, one Chinese asked, "Why did those two mice have to have a certain relationship?" Suddenly, the group looked back at the Chinese and remained speechless. The American official, the French and the Japanese who had spoken earlier all lowered their heads in shame, and did not dare to answer.In fact, the true love is not built on friendship, loyalty or blood relationship. Instead, it is based on no relationship.25. Neither of the two mice ran away immediately because .A. one was biting the otherB. the mouth of the hole was too smallC. they were not afraid of smokeD. one was trying to help the blind one26. Why did those officials lower their heads in shame according to the passage?A. They did not dare to answer.B. They had mistaken the relationship of the mice.C. They regretted driving a poor blind mouse away.D. They did not express themselves much better.27. It is clear that .A. all the mice came out of the hole easilyB. each of the people understood the relationship differentlyC. the people wanted to kill the mice with smokeD. the people knew one of the mice was blind at first sight28. The underlined part "it made sense" probably means .A. it was correctB. it was strangeC. it was funnyD. it was sweet四、完形填空（共12小题；共18分）Mr. Klein told the class that a new student, Inez, would join them soon. He 29 that Inez was deaf. She "talked" with others by using sign language. Mr. Klein knew sign language, and he decided to teach 30 students so that they could also "talk" with Inez.First, they learned to sign the letters. Some letters were hard to 31 . Other letters, such as C, were easier because the shape(形状) of the hand was the same as the shape of the letter.The 32 thing they learned was finger spelling. They signed one letter after another to spell a word. They 33 with two-letter words such as at and on. Then they spelled 34 words.Finally, Mr. Klein showed that 35 one sign could be used for a whole word. To make the sign for the word fine, a person spreads out (张开) the fingers on one hand, 36 the thumb(拇指) to the chest(前胸), and moves the hand away from the chest. Signing is not just 37 with the hands. Expressions on the face are also 38 . The students learned to sign a question mark by using expressions on the face.When Inez first entered the classroom, she looked 39 . But the students signed, "Good morning, Inez." She gave the class a big smile and signed back, "What a wonderful 40 !"29. A. hoped B. said C. guessed D. thought30. A. his B. my C. her D. our31. A. spell B. check C. remember D. write32. A. first B. only C. last D. next33. A. met B. started C. agreed D. helped34. A. newer B. easier C. longer D. nicer35. A. never B. perhaps C. still D. just36. A. joins B. fixes C. touches D. ties37. A. made B. done C. given D. chosen38. A. important B. different C. difficult D. strange39. A. serious B. surprised C. frightened D. nervous40. A. welcome B. congratulationC. progressD. success五、阅读理解（共5小题；共10分）A jobless man wanted very much to have the position of "office boy" at Microsoft. The HR manager interviewed him and then watched him cleaning the floor as a test. "You have passed the test," he said. "Give me your e-mail address and I'll send you the form to fill in and the date when you may start." The man replied, "But I don't have a computer, neither an e-mail." "I'm sorry," said the HR manager. "If you don't have an e-mail, that means you are not living. And anyone who isn't living cannot have the job."The man left with no hope at all. He didn't know what to do, with only $10 in his pocket. He thought and thought. Then he went to the supermarket and bought 10 kilos of tomatoes. He sold the tomatoes from door to door. In less than two hours, he had 20 dollars. He repeated the operation three times, and returned home with $60. The man came to know that he could make money in this way, and started to go early every day, and returned home late. Shortly, he bought a cart, then a truck, then he had his own fleet of delivery vehicles (运货车队). Five years later, the man was one of the biggest food retailers(零售商) in the U.S.One day, one of his friends asked him for his e-mail. He said, "I haven't got one." His friend couldn't believe his ears. "Can you imagine what you could have been if you had an e-mail?" The man thought for a while and replied, "Yes, I'd an office boy at Microsoft!"41. What did the man do for the test?A. He sent e-mails.B. He did the cleaning.C. He sold computers.D. He filled in forms.42. The man didn't get the job because he .A. disliked such a jobB. didn't pass the testC. didn't have an e-mailD. know nothing about computers43. The man after he left Microsoft.A. went to look for another jobB. asked for food from door to doorC. thought of an idea to make moneyD. bought a computer and got an e-mail44. Why could the man become one of the biggest food retailers in the U.S.?A. Because he had many friends to help him.B. Because he was smart and worked very hard.C. Because he had his own fleet of delivery vehicles.D. Because he wanted to show Microsoft he was living.45. What does the story want to tell us?A. Computers are very important in our daily life.B. Everyone can make a lot of money with only $10.C. The HR manager didn't find the ability of the man.D. Nothing in the world is important if we work hard.六、阅读与表达(问答式)（共5小题；共10分）Two years ago, Russian newspapers published a dramatic story about Leonid Stadnik. The man suffers from his own height: he is 257 centimeters tall. He is the tallest man in the world and he is still growing.He lives in his house in a small Ukrainian village. The man has to make quite an effort to be able to enter the house. He is almost twice as high as the doorway. The shoes that Leonid wears are 62 centimeters long. It is very hard for him to walk and even to move. Leonid can hardly control his own legs. When he walks, he needs to hold on to something—it could be a tree or the roof of his house.The giant is now a proud owner of two king size beds—the presents from local entrepreneurs(企业家). Last year Leonid welcomed the delegation(代表团) of Belgian shoe-makers. They brought many pairs of custom-made shoes and many pairs of two-meter-long shoelaces (鞋带). The old pair of worn-out shoes worn by the tallest man in the world was sold on the Internet for 2,500 euros(欧元).The profit was used to buy sweets, biscuits and other foodstuffs for children who suffered from the Chernobyl(切尔诺贝利) disaster.A telecommunication company presented Leonid with a computer at the beginning of the New Year. The PC has become the man's best friend in life. The Internet has become extremely important for this giant. That is because the World Wide Web is the only chance for the man to see the world and make friends.根据短文内容，完成下列小题。
2020-2021学年新人教版九年级数学上册周末练习及答案
2020-2021学年度第一学期九年级数学周测练习题12.09姓名:_______________班级:_______________得分:_______________一选择题:1.下列各组数中，成比例的是( )A.﹣7，﹣5，14，5B.﹣6，﹣8，3，4C.3，5，9，12D.2，3，6，122.如果从1、2、3这三个数字中任意选取两个数字组成一个两位数,那么这个两位数是偶数的概率等于( )(A)； (B)； (C)；(D)．3.已知2x=3y=4z，则x:y:z是 ( )A.2:3:4B.4:3:2C.7:6:5D.6:4:34.如图，在△ABC中，DE∥BC，分别交AB，AC于点D，E．若AD=2，DB=4，则的值为( )A. B. C. D.5.如图，⊙O为△ABC的外接圆，∠A=72°，则∠BCO的度数为( )A.15°B.18°C.2020D.28°6.如图，在同一时刻，身高1.6米的小丽在阳光下的影长为2.5米，一棵大树的影长为5米，则这棵树的高度为( )A.7.8米B.3.2米C.2.3米D.1.5米7.函数y=ax﹣a与y=(a≠0)在同一直角坐标系中的图象可能是( )A. B. C. D.8.如图，正方形ABCD的两边BC、AB分别在平面直角坐标系的x轴、y轴的正半轴上，正方形A′B′C′D′与正方形ABCD是以AC的中点O′为中心的位似图形，已知AC=3，若点A′的坐标为(1，2)，则正方形A′B′C′D′与正方形ABCD的相似比是( ). B. C. D.9.如图，D、E分别是△ABC的边AB、BC上的点，且DE∥AC，AE、CD相交于点O，若S△DOE:S△COA=1:25，则S△BDE 与S△CDE的比是( )A.1:3B.1:4C.1:5D.1:2510.如图，在△ABC 中，∠C=90°，BC=3，D，E 分别在 AB、AC上，将△ADE沿DE翻折后，点A正好落在点A′处，若A′为CE的中点，则折痕DE的长为( )A. B.3 C.2 D.111.如图是一次函数y1=kx-b和反比例函数y2=的图象，观察图象写出y1>y2时，x的取值范围是( )A.x＞3B.x＞－2或x＞3C.x＜－2或0＜x＜3D.－2＜x＜0或x＞312.如图，在Rt△ABC中，∠C=90°，AC=4，BC=3，O是△ABC的内心，以O为圆心，r为半径的圆与线段AB有交点，则r的取值范围是 ( )A．r≥1D．1≤r≤4B．1≤r≤C．1≤r≤二填空题:13.若双曲线的图象经过第二、四象限，则k的取值范围是．14.如图，点P是□ABCD边AB上的一点，射线CP交DA的延长线于点E，则图中相似的三角形有________对．15.如图，在△ABC中，D、E分别是边AB、AC上的点，DE∥BC，AD:DB=1:2，S△ADE=1，则S四边形BCED的值为_______．16.现有两个不透明盒子,其中一个装有标号分别为1,2的两张卡片,另一个装有标号分别为1,2,3的三张卡片，卡片除标号外其他均相同.若从两个盒子中各随机抽取一张卡片,则两张卡片标号恰好相同概率是________．17.菱形OABC的顶点O是原点，顶点B在轴上，菱形的两条对角线的长分别是8和6()，反比例函数的图像经过,则的值为．18.在Rt△ABC中，∠C=90°，AC=5，BC=12，若以C点为圆心、r为半径所作的圆与斜边AB只有一个公共点，则r的范围是．19.点P1(﹣1，y1)，P2(3，y2)，P3(5，y3)均在二次函数y=﹣x2+2x+c图象上，则y1，y2，y3大小关系是．2020图，平面直角坐标系中，分别以点A(﹣2,3),B(3,4)为圆心，以1、2为半径作⊙A、⊙B，M、N分别是⊙A、⊙B上的动点,P为x轴上的动点，则PM+PN的最小值等于．三作图题:21.已知△ABC在平面直角坐标系中的位置如图所示．(1)分别写出图中点A和点C的坐标；(2)画出△ABC绕点C按顺时针方向旋转90°后的△A′B′C′；(3)求点A旋转到点A′所经过的路线长(结果保留π)．22.如图，已知△ABC中，AE交BC于点D，∠C=∠E，AD:DE=3:5，AE=8，BD=4，求D C的长.23.某药品研究所开发一种抗菌新药，经多年动物实验，首次用于临床人体实验．测得成人服药后血液中药物深度y(微克/毫升)与服药时间x小时之间的函数关系如图所示(当4≤x≤10时，y与x成反比)．(1)根据图象分别求出血液中药物浓度上升和下降阶段y与x之间的函数关系式；(2)问血液中药物浓度不低于4微克/毫升的持续时间为多少小时？24.如图，已知⊙O的半径OC垂直弦AB于点H，连接BC，过点A作弦AE∥BC，过点C作CD∥BA交EA延长线于点D，延长CO交AE于点F．(1)求证:CD为⊙O的切线；(2)若BC=10，AB=16，求OF的长．25.如图，AB是⊙O的直径，点P在BA的延长线上，弦CD⊥AB，垂足为E，且PC2=PE·PO.(1)求证:PC是⊙O的切线；(2)若OE︰EA=1︰2，PA=6，求⊙O的半径；26.如图，在矩形ABCD中，AB=12cm,BC=8cm .点E、F、G分别从点A、B、C三点同时出发，沿矩形的边按逆时针方向移动。
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七年级数学上第15周练习题试卷
班级____________姓名____________
一、选择题 1．如果x y 3=，)1(2-=y z ，那么x －y ＋z 等于（ ）
A ．4x －1
B ．4x －2
C ．5x －1
D ．5x －2
2、整式2mx n +的值随x 的取值不同而不同，下表是当x 取不同值时对应的整式的 值，则关于x 的方程24mx n --=的解为( )
A.－1
B.－2
C.0
D.为其它的值 3、正方体的截面不可能是（ ）
A ， 四边形
B 、五边形
C 、六边形
D 、七边形
4．为了做一个试管架，在长为cm(6cm)a a >
径为2cm ，则x
等于（ ）
Ａ．3
4a -cm Ｂ．34a +cm Ｃ．cm Ｄ．cm
5．如图2，从A 地到C 地，可供选择的方案是走水路、走陆路、走空中.从A 地到B 地有2
条水路、2条陆路，从B 地到C 地有3条陆路可供选择，走空中从A 地不经B 地直接到C 地.则从A 地到C 地可供选择的方案有( ).
A ．20种
B ．8种
C ． 5种
D ．13种 6．下列说法中错误的是（ ）．
A ．A 、
B 两点之间的距离为3cm B ．A 、B 两点之间的距离为线段AB 的长度
C ．线段AB 的中点C 到A 、B 两点的距离相等
D ．A 、B 两点之间的距离是线段AB 7．下列说法中，（1）射线AB 和射线BA 是同一条射线 （2）延长射线MN 到C （3）延长线段MN 到A 使NA==2MN （4）连结两点的线段叫做两点间的距离正确的个数有（ ）． A ．1 B ．2 C ．3 D ．4
8. 四位学生画线段x=a-b+c 如下，其中只有一位的答案是正确的，这位学生所画的图是( )
A B C D
9．.如右上图8所示，B 、C 是线段AD 上任意两点，M 是AB
的中点，N 是CD 中点，若MN=a ，BC=b ，则线段AD 的长是（ ） A ．2()a b - B ．2a b - C ．a b + D ．a b -
第9题图
10、平面内两两相交的6条直线，交点个数最少为m 个，最多为n 个，则m ＋n 等于（ ）
A ．12
B ．16
C ．20
D ．22
11、一条铁路上有10个站，则共需要制 ( ) 种火车票。
A ．45 B ．55 C ．90 D ．110 12、如图把一个圆绕虚线旋转一周，得到的几何体是( )
13：下列左图表示一个由相同小立方块搭成的几何体的俯视图，小正方形中的数字表示该位置上小立方块的个数，则该几何体的主视图为 （ ）
14:①正数和负数统称为有理数；②一个有理数不是整数就是分数；③有最小的负数，没有最大的正数；④符号相反的两个数互为相反数；⑤a -一定在原点的左边。
A ．1个
B ．2个
C ．3个
D ．4个
15、中国古代问题：有甲、乙两个牧童，甲对乙说：“把你的羊给我一只，我的羊数就是你的羊数的2倍”。
乙回答说：“最好还是把你的羊给我一只，我们羊数就一样了”。
若设甲有x 只羊，则下列方程正确的是（ ）
A ．)2(21-=+x x
B ．)1(23-=+x x
C ．)3(21-=+x x
D ．
121
1++=
-x x
16、三条互不重合的直线的交点个数可能是（ ）
A 、0、1、3
B 、0、2、3
C 、0、1、2、3
D 、0、1、2 二、填空题： 17．若ab≠0，则等式
a b a b
+=+成立的条件是______________．
18、当250(23)a b -+达到最大值时，则22
149a b +-的值为______________。
19、已知22
15,6m mn mn n -=-=-，求22
32m mn n --的值为______________。
20：已知线段AB=4，BC=3，那么线段AC 的长度的取值范围是_________ 三：解答题：
21：一个三位数，十位上的数比个位上的数大4，个位上的数比百位上的数小2，若将此三位数的个位与百位对调，所得的新数与原数之比为7:4，求原来的三位数？
A B C D
2
2
411
3
A
B
C D
22：
33232002 13471113
()[0.25()](5 1.254)[(0.45)(2)](1) 81634242001 -⨯+----÷++-
23：解方程（1）32
122
234
x
x
⎡⎤
⎛⎫
--=+
⎪
⎢⎥
⎝⎭
⎣⎦（2）4x－1.5
0.5－
5x－0.8
0.2＝
1.2－x
0.1
24：如图所示，（1）按下列语句画出图形：
①延长AC到D，使CD=AC；②反向延长CB到E，使CE=BC；③连结DE. （2）度量其中的线段和角，你有什么发现？
（3）试判断图中两个三角形的面积是否相等？
25:如图，已知线段AB和CD的公共部分BD＝1
3
AB＝
1
4
CD，线段AB、CD的中点
E、F之间距离是10cm，求AB，CD的长．
A E C
D B F
26. 在直线L上取A，B两点，使AB=10厘米，再在L上取一点C，使AC=2厘米，M，N 分别是AB，AC中点．求MN的长度。
27、一名落水小孩抱着木头在河中漂流，在A处遇到逆水而上的快艇和轮船，因雾大而未被发现，1小时快艇和轮船获悉此事，随即掉头追救，求快艇和轮船从获悉到追及小孩各需多少时间？
28:小杰到食堂买饭，看到A、B两窗口前面排队的人一样多，就站在A窗口队伍的里面，过了2分钟，他发现A窗口每分钟有4人买了饭离开队伍，B窗口每分钟有6人买了饭离开队伍，且B窗口队伍后面每分钟增加5人。
此时，若小李迅速从A窗口队伍转移到B窗口后面重新排队，将比继续在A窗口排队提前30秒买到饭，求开始时，有多少人排队。
29、若关于x的方程2
2
36
kx m x nk
+-
=+
，无论K为何值时，它的解总是1
x=，求m、n
的值。
30.如图，点C在线段AB上，AC = 8 cm，CB = 6 cm，点M、N分别是AC、BC的中点。
（1）求线段MN的长；
（2）若C为线段AB上任一点，满足AB CB acm
+=，其它条件不变，你能猜想MN的长
度吗？并说明理由。
（3）若C在线段AB的延长线上，且满足AC CB bcm
-=，M、N分别为AC、BC的中点，
你能猜想MN的长度吗？请画出图形，写出你的结论，并说明理由。