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数学练习（一）8、如图3，在ABC △中，AC BC AB =>，点P 为ABC △所在平面内一点，且点P 与ABC △的任意两个顶点构成△PAB 、△PBC 、 △PAC 均是．．等腰三角形，则满足上述条件的所有点P 的个数为（ ▲ ） A ．3B ．4C ．5D ．611、如图4，将直角边长为5cm 的等腰直角ΔABC 绕点A 逆时 针旋转15° 后,得到ΔA B’C ’,则图中阴影部分的面积是 ▲ cm 213、一个叫巴尔末的中学教师成功地从光谱数据 95 ，1612 ，2521 ，3632 ，… 中得到巴尔末公式，从而打开了光谱奥秘的大门，请你按照这种规律，写出第n （n ≥1）个数据是 ▲18、已知Rt △ABC 中，∠C=90º。
（1）根据要求作图（尺规作图，保留作图痕迹，不写画法） ①作∠BAC 的平分线AD 交BC 于D ；②作线段AD 的垂直平分线交AB 于E ，交AC 于F ，垂足为H ； ③连接ED 。
（2）在（1）的基础上写出一对相似比不为1的相似三角形和一对全等三角形： △________∽△________；△________≌△________。
22、已知反比例函xky =图象过第二象限内的点A （－2，m ）AB ⊥x 轴于B ，Rt △AOB 面积为3 （1）求k 和m 的值；（2）若直线y=ax+b 经过点A ，并且经过反比例函xk y =的图象上另一点C （n ，－23）①求直线y=ax+b 解析式；②设直线y=ax+b 与x 轴交于M ，求△AOC 的面积；C（图3）B A图4（18题图）CB（22题图）24、如图1，以矩形OABC 的两边OA 和OC 所在的直线为x 轴、y 轴建立平面直角坐标系，A 点的坐标为（3，0），C 点的坐标为（0，4）．将矩形OABC 绕O 点逆时针旋转，使B 点落在y 轴的正半轴上，旋转后的矩形为OA 1B 1C 1，，BC 、A 1B 1相交于点M ． （1）求点B 1的坐标与线段B 1C 的长；（2）将图1中的矩形OA 1B 1C 1，沿y 轴向上平移，如图2，矩形PA 2B 2C 2，是平移过程中的某一位置，BC 、A 2B 2相交于点M 1，点P 运动到C 点停止．设点P 运动的距离为m ，矩形PA 2B 2C 2，与原矩形OABC 重叠部分的面积为S ，求S 关于m 的函数关系式，并写出m 的取值范围； （3）如图3，当点P 运动到点C 时，平移后的矩形为PA 3B 3C 3，．请你思考如何通过图形变换使矩形PA 3B 3C 3，与原矩形OABC 重合，请简述你的做法．（24题图）Ａ ＯＣＢＭＡＯ ＣＢ1M ＡＯ Ｂ1B 1C 1A xyxyxy2B2CP2AＣ(Ｐ)3C 3B 3A 图1图2图3数学练习（一）参考答案8、D 11、 25 36 13、(n ＋2)2 (n ＋2)2－418、（1）根据要求作图（尺规作图，保留作图痕迹，不写画法）①作∠BAC 的平分线AD 交BC 于D 正确； …………2分②作线段AD 的垂直平分线交AB 于E ，交AC 于F ，垂足为H 正确； ……4分 ③连接ED 正确。
8升9模拟题（一）一、基础知识( 每小题 3 分)1．下列词语中加点字的注音，全都正确的一项是( )A．两栖（qī）解剖（pāo）气息奄奄（yàn）恃才放旷（shì）B．荒谬（miù）发酵（jiào）不屈不挠（náo）长吁短叹（yū）C．束缚（sù）拮据（jū）转弯抹角（mò）混淆是非（xiáo）D．庇护（bì）笨拙（zhuō）秩序井然（zhì）一模一样（mú）2．下列词语中没有错别字的一项是( )A．真缔造型花枝招展一拍即合 B．屏障琐屑销声匿迹姗姗来迟C．驰骋苍桑兴高采烈因地制宜 D．萧索安详大厅广众左右逢源3．下列句子中加点的成语使用不恰当的一项是( )A．高考前夕，江西高三学生柳艳兵和易政勇在公交车上被歹徒砍伤，见歹徒仍在行凶，他们义愤填．．．膺．，奋力夺刀，制止了歹徒，被网友称赞为“最美考生”。
B．2014年巴西世界杯足球赛正紧张激烈地进行着，上届夺冠失利的荷兰队卷土重来．．．．，在小组赛第一场大胜卫冕冠军西班牙队，再次向大力神杯发起冲击。
C．许多网友转载了《用微波炉烹调食物会致癌》的文章，专家指出，这种骇人听闻．．．．的传言没有科学依据，微波炉加热与常规加热对食物的影响基本相同。
D．近年来，新疆考古出土了多条裤子，其中一条距今已有1500年，不仅样式是当今时髦的灯笼裤型，而且用的还是现在仍流行的百褶布料，真是不可思议。
4．下列各句中没有语病的一项是（）A．中学生之所以喜欢网络文学作品的原因，是因为这些作品不仅表现手法自由活泼，而且思想感情丰富细腻。
B．有学者认为，央视“百家讲坛”栏目将国学经典通俗化，有利于更多人了解、研究传统文化。
C．近200年来，地球的森林已有三分之一左右被采伐和毁掉，尤其在近50年，部分地区森林减少了一倍。
D．我们要养成爱读书，特别是读经典，读名著，让书香飘满我们的生活。
第6题图7题图A ．B ．C ．D ． 数学练习（二）5．函数xk 1y -=的图象与直线x y =没有交点，那么k 的取值范围是 A ．1k > B ． 1k < C ．1k -> D ．1k -<6．如图，在△ABC 中，∠C =90°，若沿图中虚线剪去∠C ，则∠1＋∠2等于（ ） A ．315° B ．270° C ．180° D ．135° 7．我们从不同的方向观察同一物体时，可以看到不同的平面图形，由6个小正方体按如图所示的方式摆放，则这个图形的左视图是（ ）11．如图，从边长为a 的大正方形纸板中间挖去一个边长为b 的小正方形后，将其裁成四个相同的等腰梯形（如图甲），然后拼成一个平行四边形（如图乙）．那么通过计算阴影部分的面积可以验证我们学过的什么公式？答：_________ ．12．若多项式m x x +-2在有理数范围内能分解因式，把你发现字母m 的取值规律用含字母n （n 为正整数）的式子表示为 ．17．(本小题满分5分)如图，等腰直角△ABC 中，∠ABC=90°，点D 在AC 上，将△ABD 绕顶点B 沿顺时针方向旋转90°后得到△CBE.⑴求∠DCE 的度数；⑵当AB=4，AD ∶DC=1∶3时，求DE 的长.解：四、解答题（共2道小题，共10分）18．（本小题满分5分）如图，在梯形ABCD 中, AB//DC, ∠ADC=90︒, ∠ACD=30︒ ，∠ACB=45︒ ，BC=23，求AD 的长.解:11题图21（本小题满分6分）某公司投资某个工程项目，现在甲、乙两个工程队有能力承包这个项目．公司调查发现：乙队单独完成工程的时间是甲队的2倍，甲、乙两队合作完成工程需要20天；甲队每天的工作费用为1000元、乙队每天的工作费用为550元．根据以上信息，从节约资金的角度考虑，公司应选择哪个工程队、应付工程队费用多少元？解：六、解答题（本题满分4分）22．取一张矩形纸片进行折叠，具体操作过程如下：第一步：先把矩形ABCD对折，折痕为MN，如图1；第二步：再把B点叠在折痕线MN上，折痕为AE，点B在MN上的对应点为B'，得R t△A B'E，如图2；第三步：沿EB'线折叠得折痕EF，使A点落在EC的延长线上，如图3．利用展开图4探究：（1）△AEF是什么三角形?证明你的结论；（2）对于任一矩形，按照上述方法能否折出这种三角形?请说明你的理由．解：图1 图2图3 图4数学练习（二）参考答案11． 平方差公式； 12． ()1--=n n m17．解：（1）∵△CBE 是由△ABD 旋转得到的，∴△ABD ≌△CBE ，…………………………1分∴∠A ＝∠BCE ＝45°，∴∠DCE ＝∠DCB ＋∠BCE ＝90° …………………2分（2）在等腰直角三角形ABC 中，∵AB ＝4，∴AC ＝42.又∵AD ︰DC ＝１︰3，∴AD=2，DC=32.…………………………4分由（１）知AD ＝CE 且∠DCE ＝90°,∴DE 2＝DC 2＋CE 2＝2＋18＝20，∴DE ＝25.…………5分四、解答题（共2道小题，共10分）18．（本小题满分5分）解: 过点B 作BE ⊥AC 于E,则∠AEB=∠BEC= 90︒. ………1分∵ ∠ACB=45︒ ，BC=23，∴ 由勾股定理，得BE=EC=3. ………2分∵ AB//DC,∴ ∠BAE=∠ACD=30︒ . 又∵ AEBE = 30tan , ∴ AE=33. ………3分 ∴ AC=AE ＋EC=33+3. …………………4分在Rt △ADC 中,∠D=90︒, ∠ACD=30︒ ,∴ AD=.233321+=AC …………………………5分 21．解：设甲队单独完成需x 天，则乙队单独完成需要2x 天．……………1分 根据题意，得111220x x +=.…………3分 解得30x =．……………………4分 经检验30x =是原方程的解，且30x =，260x =都符合题意．∴应付甲队30100030000⨯=（元）．应付乙队30255033000⨯⨯=（元）．……………5分 ∴公司应选择甲工程队，应付工程总费用30000元．……………………………6分 六、解答题（本题满分4分）22．解：（1）△AEF 是等边三角形．由折叠过程可得：60BEA AEF FEC ∠=∠=∠=︒．∵BC ∥AD ，∴60AFE FEC ∠=∠=︒． ∴△AEF 是等边三角形．（2）不一定．当矩形的长恰好等于等边△AEF 的边AF 时，即矩形的宽∶长＝AB ∶AF ＝sin60°＝2:3时正好能折出． 如果设矩形的长为a ，宽为b ，可知当a b 23≤时，按此种方法一定能折叠出等边三角形； 当a b a ＜＜23时，按此法无法折出完整的等边三角形． 图 1 图2 图3 图4。
八年级到九年级暑期衔接Day 5一、根据汉语提示填写单词1. You can lift the box with a ________(手指) or two.2. Don't ________(扔) paper around the classroom.3. He doesn't have a sister and ________(也不) do I.4. Could I ________(借) your bike? Mine is broken.5. I like to sweep the floor, but I ________(讨厌) to do the dishes.二、语法填空阅读下面短文，在空白处填入一个适当的词，或填入括号中所给单词的正确形式。
Lin is a very kind girl. She is always ready to help people who are 6________ trouble. Now Lin is studying at the University of Texas. At the same time, she volunteers 7________ (teach) at Heart House in her free time. Heart House is a local afterschool study program for children. It provides some extra 8________(educate) for children who are not doing 9________(good) in school.Lin goes to Heart House to teach the children 10________(two) a week. She also makes a website for Heart House. In this way, people will learn more 11________ Heart House and better help the children there. 12________(thank) to Lin's website, every week 125 volunteers spend two hours helping the children at Heart House now. “13________ Lin's website, Heart House would never be able to have enough volunteers，”the program leader said.“I feel happy to teach those kids 14_______ to study. I won't give up 15________(volunteer). I hope to continue teaching kids who need help，”Lin said.三、完形填空This is a true story. There was a player named Jerry in the football team. He liked playing __16__，but he wasn't good at it. So he had few chances to play for his team. He __17__ very sorry for it.One day, his father died from a terrible illness, he had to return to his __18__ to do something. After that, an important __19__ was going to begin. He found the coach at once and he asked the coach whether he could take part in the match or not. He was not good at skills, so the coach would not __20__ him to take part in the match at first. But now, as he relented(心软), he agreed to let Jerry play for only three __21__. When the time was up, he would be changed by others. On the court(球场), Jerry played very well. The coach was very pleased __22__ him. Three minutes __23__ the coach made Jerry keep staying on the court. Jerry kept on his __24__ performance(表现), leading the team to __25__ the match.The coach hugged him __26__ and said, “Kid, you have never been so fast, so strong and so skilled. What happened on earth(究竟)？” Jerry said, “There was something wrong with my father's eyes, __27__ he has never watched my match. Now, he's __28__ to the heaven and finally can watch my match. As soon as I think of my father watching me, I don't feel tired at all, and I feel __29__，too.”The coach understood: __30__ can drive everything. Do you agree with him?()16. A. football B. basketball C. tennis D. baseball()17. A. sounded B. smelt C. tasted D. felt()18. A. school B. home C. garden D. court()19. A. meeting B. activity C. match D. ceremony()20. A. order B. allow C. teach D. tell()21. A. minutes B. days C. hours D. seconds()22. A. in B. for C. with D. under()23. A. ago B. after C. before D. later()24. A. bright B. humorous C. proud D. excellent()25. A. win B. lose C. beat D. get()26. A. excitedly B. directly C. sadly D. gently()27. A. but B. or C. and D. so()28. A. been B. gone C. returned D. come()29. A. worried B. active C. hungry D. awful()30. A. Hobby B. Friendship C. Love D. Business四、阅读理解What does it feel like to break a bone(骨头)? It's different for everyone, but the pain is often serious. If the break is small, however, the person may feel little pain. If you think that you or someone else has broken a bone, the most important things to do are to stay calm, make the hurt person comfortable, and call the doctor. Do not move the hurt body part because movement could make it worse.To treat the break, the doctor will need to take an Xray first. This gives the doctor the information that if he or she needs to set the bone. Then, put it back to its normal place. If the bone is large or it is broken in more than one place, the doctor may need to use metal pins(钢钉) to set it. After the bone has been set, the next step is usually putting on a cast, the special hard thing that will keep the bone in place for a month or two.Your bones are very good at becoming healthy themselves. Broken bones will make many new cells and tidy blood vessels(血管). These covers both end the broken part and close up the break until the bone is as whole and strong as before.()31. When someone breaks his bone, we shouldn't ________．A. stay calmB. ask the doctor for helpC. comfort the hurt personD. move the hurt part()32. According to Paragraph 2, the right order of treating the break is ________．a. take an Xrayb. use metal pins to set itc. put it back to its normal placed. put on a castA. a→c→b→dB. a→b→c→dC. a→d→c→bD. a→c→d→b()33. The best title for the passage would be ________．A. What Causes the Broken BonesB. What You Should Know About Broken BonesC. How to Know If a Bone Is BrokenD. How Broken Bones Become Healthy Themselves()34. We can most probably read the passage ________．A. in a storybookB. in a history bookC. in a health care bookD. in a geography book参考答案一、1. finger 2. throw 3. neither 4. borrow 5. hate二、6.in 7.to teach cation 9.well 10. twice11.about 12.Thanks 13.Without 14.how 15．volunteering三、16—20 ADBCB21—25 ACDDA26—30 ADBBC四、31—34 DABC。
初三化学暑假作业第一单元1．物理变化和化学变化的本质区别(也就是判断依据)是：变化时是否有新物质生成。
2．下列现象属于化学变化是__（1）（3）（4）（5）（10）(填序号)(1)铁生锈(2)石蜡熔化(3)纸张燃烧(4)食物腐烂(5)铜在潮湿的空气里生成铜绿(6)潮湿的衣服被晒干了(7)雪融化(8)向玻璃片哈气，会出现一层水雾。
(9)电灯发光(10)植物光合作用3．下列有关物质性质的描述中，属于物理性质是_（2）（3）（6）（9）（10）__(填序号)，(1)酒精能燃烧(2)浓盐酸能挥发(3)常压下，水的沸点是100℃(4)以粮食为原料能酿酒。
(5)二氧化碳能使澄清的石灰水变浑浊(6)空气是没有颜色、没有气味的气体(7)氧气具有助燃性(8)铁在潮湿的空气里易生锈(9)浓氨水具有挥发性(10)食盐易溶于水4．药品的取用(1) 固体药品通常保存在__广口瓶_里(2)液体药品通常盛放在__细口__瓶里，常用倾倒法取用。
倾倒液体药品操作要点：瓶塞_倒___放；标签___向着手心____；试剂瓶口__紧挨试管口。
(3) 用量筒量取液体读数时，视线要与凹液面的最低点保持水平(如果俯视时，读数高于实际数值；如果仰视时，读数低于实际数值)；4．检查装置的气密性（如右图）先_将右侧导管伸入水中__再__用水紧握试管__，如果水中的导管口有__气泡__冒出，说明装置不漏气。
5．把玻璃管插入带孔橡皮塞或连接玻璃管和胶皮管时，一般先把玻璃管口用__水___润湿，再连接。
6．洗涤玻璃仪器洗干净的标准：_内壁附着的水既不聚成水滴，也不成股流下_____第二单元 课题11．二百多年前，法国化学家__拉瓦锡___用定量的方法研究了空气的成分。
2．空气的成分按体积计算，大约是：氮气__78%___、氧气_21%__、稀有气体_0.94%__、二氧化碳___0.03%__、其他气体和杂质0.03％。
3．纯净物由_一_种物质组成；混合物由_两种或两种以上的物质混合而成的。
数学练习（四）5．若1x 、2x 是一元二次方程0572=+-x x 的两根，则2111x x +的值是（ ） （A ）57 B ）57- （C ）75 （D ）75- 6．某超市进了一批商品，每件进价为a 元，若要获利25%，则每件商品的零售价应定为（ ）（A ）a %25 （B ）()a %251- （C ）()a %251+ （D ）%251+acm ）。
将它们拼成如图2的新几何体，则该新几何体的体积为（ ）33．72πcm 3 D ．84πcm 312．估计215-与0.5的大小关系是：215-________0.5（填“>”、“=”、“<”）。
14．若不等式组⎩⎨⎧>->-022x b a x 的解集是11<<-x ，则=+2008)(b a ________。
图2图110. 将图（1）所示的正六边形实行分割得到图（2），再将图（2）里的三个小正六边形的其中之一按同样的方式实行分割得到图（3），接着再将图（3）中最小的三个正六边形的其中之一按同样的方式实行分割…，则第n 图形中共有 个六边形．（提示：可设y=an 2+bn+c,把代入求a,b,c.再求y=?）15．分别剪一些边长相同的①正三角形，②正方形，③正五边形，如果用其中一种正多边形镶嵌，能够镶嵌成一个平面图案的有……………………【 】 A.①② B.②③ C.①③ D.①②③都能够10．根据图中提供的信息，用含n （n ≥1，n 是正整数） 的等式表示第n 个正方形点阵中的规律是：_____.16. 如图所示，将边长为8cm 的正方形纸片ABCD 折叠，使点D 落在BC 中点E 处，点A 落在F 处，折痕为MN ，则线段CN 的 长是………（ ） A. 2 B. 3 C. 4D. 5⎩⎨⎧==⎩⎨⎧==⎩⎨⎧==73,42,11y n y n y n ……EDCBA8．若等腰△ABC 的底边和腰长分别是一元二次方程01582=+-x x 的两个根，则这个等腰三角形的周长是（ ）A ．11 B ．13 C ．11或13 D ．无法确定 13．如图，DE 是△ABC 的中位线，AB+AC=16cm ，DE=3cm ，则梯形DBCE 的周长为 ．23、（本题满分12分）如图，在直角梯形纸片ABCD 中，AB ∥DC ，︒=∠90A ，AD CD >，将纸片沿过点D 的直线折叠，使点A 落在边CD 上的点E 处，折痕为DF ．连接EF 并展开纸片．（1）求证：四边形ADEF 是正方形；（2）取线段AF 的中点G ，连接EG ，如果CD BG =，试说明四边形GBCE 是等腰梯形．24．如图，以O 为原点的直角坐标系中，A 点的坐标为（0，1），直线x =1交x 轴于点B ．P 为线段AB 上一动点，作直线PC ⊥PO ，交直线x =1于点C ．过P 点作直线MN 平行于x 轴，交y 轴于点M ，交直线x =1于点N ．（1）当点C 在第一象限时，求证：△OPM ≌△PCN ； （2）当点C 在第一象限时，设AP 长为m ，四边形POBC 的面积为S ，请求出S 与m 之间的函数关系式，并写出自变量m 的取值范围；（3）当点P 在线段AB 上移动时，点C 也随之ECBDAG F在直线x=1上移动，△PBC能否成为等腰三角形？如果可能，求出所有能使△PBC成为等腰三角形的点P的坐标；如果不可能，请说明理由．数学练习（四）参考答案5.C6.D 9.A 12.D 14．－2a 10、3n-2 15、A ； 18、C 18、C10、 . 15、C . 16、B. 8、C 13．17cm ．23、解：（1）∵△ADF ≌△EDF∴∠DEF=∠A=90°……………………1分 ∵AB ∥DC∴∠ADE=90°…………………………1分 ∴四边形ADEF 为矩形………………2分又∵DA=DE ∴ADEF 为正方形……………………2分 （2）过C 作CH ⊥AB ，垂足为H ……………………1分∵CE ∥BG ，CE≠BG ∴EGBC 是梯形……………………1分 ∵CH ⊥AB ∴∠CHA=90°又∵∠CDA=∠DAH=90° ∴ CDAH 为矩形 ∴CD=AH ………1分 又∵BG=CD ∴BG=AH ∴BH=AG 又∵AG=GF ∴GF=HB ………1分又∵∠EFG=∠CHB ，EF=CH ∴ △EFG ≌△CHB ……1分 ∴EG=CB ∴ EGBC 为等腰梯形……1分24．（1）证明：∵OM ∥BN ，MN ∥OB ，∠AOB=90°， ∴四边形OBNM 为矩形。
新课练13分子热运动一、单选题1.如图所示的各种现象中，能用来说明分子间存在引力的是（）A.0.5L水和0.5L酒精混合后体积小于1LB.煤堆放在墙角处多年后，墙角处变黑了C.将两铅块压紧后可悬挂物体，而两铅块不分开D.抽掉玻璃板后，两瓶中的气体混合了2.小明在学习“从粒子到宇宙”的知识后，有下列认识，其中正确的是（）A.扫地时灰尘飞舞能说明分子在做无规则运动B.海绵容易被压缩能说明分子间有空隙C.在探索比分子更小的微观粒子的历程中，卢瑟福首先发现了电子D.用扩散现象说明分子在运动是转换法的研究方法3.用分子的观点解释下列现象，不正确的是（）A.气体受热膨胀——气体分子间的距离变大B.走过花园，闻到花香——分子在不停地做热运动C.两块平整的玻璃不能压成一块玻璃——分子之间的斥力大于引力D.水和酒精混合后总体积变小——分子间有间隔4.世界卫生组织正式发布通告，将新型冠状病毒感染的肺炎将正式被命名为“2019冠状病毒病”（COVID-19），冠状病毒颗粒形状是球形的，直径非常小，可以在空气中悬浮很长一段时间，COVID-19病毒直径大概是（）A.0.1nmB.100nmC.0.1mmD.10mm5.机场安检过程中，防暴犬功不可没.即使隔着多层包装，防暴犬也能嗅出炸药的气味，这说明组成炸药的分子（）A.一直处于静止状态B.处于永不停息的运动中C.相互之间存在排斥力D.相互之间存在吸引力6.如图所示，在盛有冷水和热水的烧杯中各滴入一滴红墨水，观察到红墨水在热水杯中扩散的快.关于这一实验的目的，下列说法正确的是（）A.比较烧杯内水的内能大小B.比较两滴墨水的内能大小C.说明分子无规则运动的剧烈程度与温度有关D.说明热量可以从高温物体传递给低温物体7.二氧化氮气体的密度大于空气的密度，在装有红棕色二氧化氮气体的瓶子上面，倒扣一个空瓶子，使两个瓶口相对，之间用一块玻璃板隔开，如图所示。
抽掉玻璃板一段时间后，两种气体会在两个瓶子内均匀混合.针对上述现象，下列说法正确的是（）A.气体是由分子组成的B.气体分子间存在引力和斥力C.气体分子在做永不停息的无规则运动D.温度越高，气体分子无规则运动越剧烈8.对下列现象的解释，正确的是（）A.打开香水瓶盖后，能闻到香味，说明分子在永不停息地做无规则运动B.封闭在容器内的液体很难被压缩，说明分子间有引力C.用手捏海绵，海绵的体积变小了，说明分子间有间隙D.铅笔笔芯用了一段时间后会变短，说明分子间有斥力9.关于分子动理论。
数学练习（十三）7. 有一列数1a ，2a ，3a ，，n a ，从第二个数开始，每一个数都等于1与它前面那个数的倒数的差，若12a =，则2009a 为 A ．2009B ．2C ．21 D ．1-11．如图，P 为菱形ABCD 的对角线AC 上一点，AB PE ⊥于E ，AD PF ⊥于F ，3=PF ，则PE 的长是 .12．观察下列有序数对：)1,3(-，)21,5(-，)31,7(-，)41,9(-，…，根据你发现的规律，第100个有序数对是 ． 15．反比例函数xky =的图象在第一象限的分支上有一点A （2，3），P 为x 轴正半轴上的一个动点. （1）求反比例函数的解析式；（2）当P 在什么位置时，OPA ∆为直角三角形，求出此时P 点的坐标．22．如图，正方形网格中的每个小正方形的边长都是1，每个小格的顶点叫做格点．（1）在图１中以格点为顶点画一个面积为5的正方形；（2）在图２中以格点为顶点画一个三角形，使三角形三边长分别为3、4、5；（3）在图３中以格点为顶点画一个三角形，使三角形三边长分别为2、5、13．FEP D CBA第11题第22题图图１ 图2 图324．如图，在平面直角坐标系中，O 为坐标原点，AOB ∆为等边三角形，点A 的坐标是（34，0），点B 在第一象限，AC 是OAB ∠的平分线，并且与y 轴交于点E ，点M 为直线AC 上一个动点，把AOM ∆绕点A 顺时针旋转，使边AO 与边AB 重合，得到ABD ∆．（1）求直线OB 的解析式；（2）当M 与点E 重合时，求此时点D 的坐标；（3）是否存在点M ，使OMD ∆的面积等于33，若存在，求出点M 的坐标； 若不存在，请说明理由．25．（1）如图1，四边形ABCD 中，CB AB =，︒=∠60ABC ，︒=∠120ADC ，请你 猜想线段DA 、DC 之和与线段BD 的数量关系，并证明你的结论；（2）如图2，四边形ABCD 中，BC AB =，︒=∠60ABC ，若点P 为四边形ABCD 内一点，且︒=∠120APD ，请你猜想线段PA 、PD 、PC 之和与线段BD 的 数量关系，并证明你的结论．图2第25题第24题 CBA 0yxEO 图１数学练习（十三）参考答案7．C 11.3 12. )1001,201(- 15．解：（1）将)3,2(A 代入xky =， ……………………………………………1分 得 6=k ．所以函数解析式为xy 6=． ……………………………………………2分 （2）当︒=∠90OPA 时，)0,2(P ． ……………………………………………3分 当︒=∠90OAP 时，过A 作x AH ⊥轴于H ，由△OAH ∽△APH ， ……………………………………………4分得 PHAHAH OH =．即 292322===OH AH PH ． 所以，213292=+=OP ．此时，点P 的坐标为（213，0）． ……………………………………………5分 22．解：如图所示，每问1分，共3分．24．解：（1）B （32，6）；OB l ：x y 3=． ……………………2分（2）如图1，由题意x DA ⊥轴，︒=∠=∠30BAD EAO ．此时 823===OA AE DA ，即点D （34，8）． ……………………4分图1图 2 图3第22题ABCDExyOEE（3）如图2、图3，过M 作x MN ⊥轴，设a MN =，当M 在x 轴上方时，由︒=∠30OAM ，∴ a MA 2=，a NA 3=．=∆O M D S 33234213)2(21)334(21=⋅⋅-⋅++⋅-a a a a a a ． 解得3=a ．…5分 当M 在x 轴下方时，由︒=∠30NAM ，∴ a MA 2=，a NA 3=．=∆O M D S 33)334(213)2(2123421=⋅+-⋅++⋅⋅a a a a a a ． 解得1=a ．……6分 ∴ 1M （3，3），2M （35，1-）．………………7分 25．解：（1）如图１，延长CD 至E ，使DA DE =．可证明EAD ∆是等边三角形． ……………………………………………1分 联结AC ，可证明BAD ∆≌CAE ∆． ……………………………………………2分 故BD CE CD DE CD AD ==+=+．……………………………………………3分（2）如图２，在四边形ABCD 外侧作正三角形D B A '， 可证明C B A '∆≌ADB ∆，得DB C B ='．……………………………………………4分 ∵ 四边形DP B A '符合（1）中条件，∴ PD AP P B +='． ……………………………………………5分 联结C B '，ⅰ）若满足题中条件的点P 在C B '上， 则PC B P C B +'='． ∴ PC PD AP C B ++='．∴ PC PD PA BD ++= ． ……………………………………………6分 ⅱ）若满足题中条件的点P 不在C B '上，∵ PC B P C B +'<'，∴ PC PD AP C B ++<'．∴ PC PD PA BD ++<． ……………………………………………7分 综上，PC PD PA BD ++≤． ……………………………………………8分图 1图2第25题。
Day 1新目标英语暑假作业衔接教材（八升九）一、.根据句意及汉语提示完成句子1．I plan to send her some flowers as an ________ (表达方式) of thanks.2．English ________(语法) is boring, but it is important.So you must learn it well.3．It is a ________ (秘密) between you and me. Don't tell it to others.4．Could you tell me when Columbus ________ (发现) America?5．Try to guess the ________ (意思) of the word first.二、语法填空阅读下面短文，在空白处填入一个适当的词，或填入括号中所给单词的正确形式(每空不多于3个单词)。
Students learn their lessons in class. They sit in the classroom listening to their teachers. This is a way of 6.________(learn). Is this the only way 7.________ students to learn? Of course not. There is another way to learn. Students can teach 8.________(they). For example, if you cannot remember something 9.________ you are doing your homework, what will you do? You can look through your book to find the answer.10．________do you teach yourself? The first thing you should do is reading. Read something you are 11.________(interest) in, and you have to read. The12.________(two) is that you must ask yourself questions. A clever student is usually good at asking questions. The third is to answer the questions yourself by 13.________(work) hard, by reading books, and sometimes by asking other people. These are the ways of teaching yourself. If you keep doing 14.________these for a long time, you are sure 15.________(make) great progress in your study.三、.完形填空I'm enjoying my stay in Canada. It is my first experience of being abroad, and I am trying to __16__ as much as possible. Classes here are much more fun and very different from the classes in __17__. In China there are very few opportunities to practice __18__ and listening. Although many Chinese students have good __19__，their speaking is not good. Studying English at Fern is much more practical. We actually __20__ the language we are learning. I couldn't speak any English at all when I __21__ here. Thankfully, after about a month, things started getting __22__ and I made friends and started to settle in(适应). I am really __23__ to learn English here andFern is a very good language school.I have always wanted to have a sister. In my Canadian host family the__24__ has come true. __25__ the first day when I arrived, my host family welcomed me warmly. All the family members were __26__ and helpful, and they made me feel at home at once.My __27__，Joise, is very kind. She often explains their manners to me. Her mother explains ordinary things like housework. Together they __28__ me study and understand Canada. Joise told me a __29__. Last year, she met a Chinese student on a plane. She said she felt sorry because she did not say __30__ to the girl.I'm happy to live in Canada. I think it will be an important experience in my life.()16.A.travel B．learn C．think D．speak()17.A.Japan B．Canada C．China D．America()18.A.playing B．reading C．writing D．speaking()19.A.grammar B．writing C．English D．pronunciation ()20.A.write B．read C．hear D．use()21.A.stayed B．arrived C．returned D．left()22.A.harder B．worse C．busier D．easier()23.A.sad B．sorry C．happy D．afraid()24.A.fact B．truth C．dream D．advice()25.A.In B．For C．On D．During()26.A.serious B．friendly C．famous D．expensive ()27.A.sister B．father C．brother D．mother()28.A.want B．tell C．help D．order()29.A.joke B．project C．program D．story()30.A.everything B．anythingC．something D．nothing四、阅读理解Since 2018, the English listening and speaking test in Beijing has to be separated from the written one. And the listening and speaking test for all students who are taking senior high school entrance exams (中考) in Beijing is becoming more and more important. The test counts for 40 points in the whole English exam. During the 30-minute test, students have to fill in blanks,answer questions and retell stories after listening to different materials.The test is taken on a computer. They can take the test twice—once in December and again in March—to try to get a possible higher score.“It pushes us to speak. Though it was hard at the beginning, it's a good thing，” said Liu Haoxuan, from Beijing Dayu Middle School. He got a low score when he first took it last term. But he kept working hard in order to improve his pronunciation and other skills. He practiced speaking in front of a mirror every day. Later, he got a score of 39 in the test.Liu Tianyou, 14, from Beijing Yuying Middle School, has his own way to prepare for the spoken English test. He uses apps to take practice tests every day. “The apps will score your performance so that you can improve accordingly，” he said. “Also, the practice tests help me learn to take not es properly. They help me grasp topic sentences and key words.”()31.What do we know about the English listening and speaking test?A．Students have to take it twice a year.B．The test was introduced many years ago.C．It counts for 40 points in the whole English exam.D．Students can get high scores in the test easily.()32.What do students have to do in the test?a. Fill in blanks.b. Answer questions.c. Retell stories.d. Write stories.A．abc B．abdC．acd D．bcd()33.What do we learn from Liu Haoxuan's story?A．Practice makes perfect.B．Knowledge comes from questioning.C．Think twice before acting.D．Two heads are better than one.()34.What do we know about Liu Tianyou?A．He got a score of 39 in the test.B．He practiced for the test by using apps.C．He failed the English listening and speaking test.。
初二英语暑假作业参考答案第一课时一. 1. magazines 2. honest 3. secret 4. believe 5. special6. appearance7. smiling8. solve9. correctly 10. pleasant二. 1. tall 2. willing 3. unhappy 4. humorous 5. really6. funny7. jokes8. feet9. pleased 10. the most carefully三. 1. to drink 2. laugh 3. to know 4. has sold 5. was given6. doesn’t rain, will go7. have , been8. has gone, would come9. travels 10. wants, finishes四. 1---5 C D C A D五. 1. Does, have, or 2. doesn’t wear 3. Why is 4. What is, like 5. keeps secrets六. 1. I don’t know much about this school.2. I miss my classmates in my old school.3. I just moved to Shanghai with my parents.4. My daughter is crazy about piano.5. I work in a new middle school.七. no field instead heavy really ever looked now means tiredness第二课时一. 1. generous 2. true 3. humor 4. advertisements 5. agree二. 1. cry 2. the coldest , the hottest 3. big, smaller 4. friendly 5. ours6. differences7. prettier8. more popular9. useful 10. more三. 1. found 2. aren’t 3. were watching 4. be taken 5. has taught6. to travel7. will be invited8. opening9. is raining 10. are sent四. 1---5 C C D C五. 1. slimmer than 2. What does , look like 3. taller any other4. What odes, want be5. what to do六. 1. This bridge is about 30 metres long.2. Make sure to finish the work before Friday.3. Linda is tall and slim, she looks really lovely.4. There are many places of interest in Beijing.5. The whole world is in front of me.七. 1. importance/ value eful/ valuable 3.Time4.lost /missing/ past5.leads/ contributes6.best第三课时一. 1. correctly 2. admire 3. practice 4. taste 5. even6. reader7. nervous8. encouragement9. wears 10. information二. 1. northern 2. unnecessary 3. polluted 4. widely 5. the most famous6. foggier7. arrival8. shaking9. the most popular 10. well, musical三. 1. shall, meet 2. am, won’t visit 3. lost, Did, see 4. Is , produced 5. have seen, arrived6. were playing7. closes8. was, lost9. Was, sent 10. were invited四. 1---5 B B C B B五. 1. older 2. less important 3. Is 4. the tallest , No one 5. How long does六. 1. He plans to do morning exercise every day.2. I feel uncomfortable during most of the trip.3. The Chinese team went to the final but didn’t win yesterday.4. It takes over an hour from the school to the World Park by underground.5. You can see the whole town from the top of the tower.七. 1---5 B A C D B 6---10 D C A D B第四课时一. 1. movies 2. languages 3. practise 4. popular 5. article6.shining7. beautiful8. harmless9. meaning 10. delightful二. 1. unhealthy 2. interesting 3. pleasant 4. more comfortable 5. helplesseful7. wonderful8. alone, lonely9. unhealthy 10. luckies7.三. 1. rises 2. were playing 3. will become 4. have been 5. taught6.How, found, found7. has gone8. Driving9. chatting 10. to spend四. 1-5 BACBA五. 1. too young to go out alone 2. take care of his mother at home 3. is too small for4.more beautiful5. her an imagination girl六. 1. different from my brother's 2. the same as that 3. the fewest points4.less time on his homework5. same size as mine七. 1-5 CCADA第五课时一. 1. hero 2. British 3. humorous 4. pop 5. dramas6.includes7. Tower8. skiing9. clapped 10. characters二. 1. the most important 2. boring 3. useless 4. endless 5. unpopular6.successfully7. watching8. unlucky9. silently 10. foggy三. 1. crying 2. took 3. have been 4. to see 5. hike6.visit7. Traveling8. has gone9. to go 10. twice四. 1-5 BBBCC五. 1. a Grade 7 student 2. when you are 16 years old 3. takes; a lot of time to collect stamps4. drives me to school5. to do六. 1. Spring is the best time to visit Chinese gardens. You must be very pleased.2.It is fantastic to have a bird's-eye view of HongKong.3.We screamed with excitement when the roller coaster were moving at high speed.4.The boy left his hometown when he was ten years old. He has been away for nearly 20 years.5.Mr Li went to Beijing for a meeting. He has been in Beijing for 3 days. He has been there three times.七. 1-5 CBAAB第六课时一．根据句意及所给的中文、英文解释、首字母写单词。
1. coffee2. ourselves3. president4. past5. greetings6. to exercise7. metal8.stomach9. invited 10.coach二．用所给单词的适当形式填空1. past2.beginning3. excited4. phots5. cities三．用所给动词的适当形式填空1. to lose2. invited3. chatting4. making5. to visit四．单项选择1. B2. C3. B4. C5. A五．句型转换1. enjoying herself2. What colour was3. Where did meet4. unhappy in the beginning5. taughthimself六．将所给的中文翻译成英文1. feel sick any more2. took us three days3. look likes the real ones4. around the world , popmusic 5. climbs hills to keep healthy every day七．任务型阅读理解仔细阅读下面的短文并按要求完成后面的小题.1. beliefs, opinions2. I should correct myself and apologize to those that I have offended.3. 你要设身处地为别人着想。
