【简介】以下是小编为大家收集的初二第一学期数学期末测试题（共10篇），希望对大家有所帮助。在此，感谢网友“伤痕累累”投稿本文！
和y2(元)与参演男生人数x之间的函数关系式;
(2) 问：该学校购买哪家制衣公司的服装比较合算?请说明理由.
24.(12分)已知一次函数的图象a过点m(-1，-4.5)，n(1，-1.5)
(1) 求此函数解析式，并画出图象(4分);
(2) 求出此函数图象与x轴、y轴的交点a、b的坐标(4分);
(3) 若直线a与b相交于点p(4，m)，a、b与x轴围成的△pac的面积为6，求出点c的坐标
(5分)。
25.( 12分)某商场筹集资金13.16万元，一次性购进空调、彩电共30台.根据市场需要，这些空调、彩电可以全部销售，全部销售后利润不少于1.56万元，其中空调、彩电的进价和售价见表格.
空调 彩电
进价(元/台) 5400 3500
售价(元/台) 6100 3900
设商场计划购进空调x台，空调和彩电全部销售后商场获得的利润为y元.
(1) 试写出y与x的函数关系式;
(2) 商场有哪几种进货方案可供选择?
(3) 选择哪种进货方案，商场获利最大?最大利润是多少元?
26.(12分)在一条笔直的公路上有a、b两地，甲骑自行车从a地到b地;乙骑自行车从b地到a地，到达a地后立即按原路返回，如图是甲、乙两人离b地的距离y(km)与行驶时间x(h)之间的函数图象，根据图象解答以下问题：
(1) 写出a、b两地的距离;
(2) 求出点m的坐标，并解释该点坐标所表示的实际意义;
(3) 若两人之间保持的距离不超过2km时，能够用无线对讲
机保持联系，请直接写出甲、乙两人能够用无线对讲机
保持联系时x的取值范围.
27.(12分)如图，直线l1 与x轴、y轴分别交于a、b两点，直线l2与直线l1关于x轴对称，已知直线l1的解析式为y=x 3，
(1) 求直线l2的解析式;
(2) 过a点在△abc的外部作一条直线l3，过点b作be⊥l3于e,过点c作cf⊥l3于f，请画出图形并求证：be cf=ef
(3) △abc沿y轴向下平移，ab边交x轴于点p，过p点的直线与ac边的延长线相交于点q，
与y轴相交与点m，且bp=cq，在△abc平移的过程中，①om为定值;②mc为定值。
在这两个结论中，有且只有一个是正确的，请找出正确的结论，并求出其值。
答案
一、选择题
1―5 c b b b c 6―10 c c a a d
二、填空题
11. 3 12.
13. 5 14. x≥-2
15. 6 16. (-3，-5)
17. 48 18. 3
三、解答题
19.(1)4 (2)x=2或x=-4
20. 略
21. (1)△acd是等边三角形 (5分) (2)∠bae=120°(5分)
22. (1)略 (2)4 (3)(3,1)
23. (1)y1=0.7[120x 100(2x100)] 2200=224x4800;
y2=0.8[100(3x100)]=240x8000; (6分)
(2)由题意，得
当y1>y2时，即224x4800>240x8000，解得：x<200
当y1=y2时，即224x4800=240x8000，解得：x=200
当y1<240x8000，解得：x>200
即当参演男生少于200人时，购买b公司的服装比较合算;
当参演男生等于200人时，购买两家公司的服装总费用相同，任一家公司购买;
当参演男生多于200人时，购买a公司的服装比较合算. (4分)
24. (1)y=1.5x-3 图像略 (4分) (2)a(2,0) b(0,-3)(4分)
(3)p(4,3) c(-2,0)或(6,0) (5分)
25.(1)y=(61005400)x (39003500)(30x)=300x 1;
(2)12≤x≤14 ;略
(3)空调14台，彩电16台;16200元
26.(1)20千米
(2)m的坐标为( ，40/3)，表示 小时后两车相遇，此时距离b地40/3千米;
(3) 当 ≤x≤ 或 ≤x≤2时，甲、乙两人能够用无线对讲机保持联系.
27. (1) y=-x-3; (2)略 (3) ①对，om=3
一、选择题 (每题3分，共30分)
1.如图，下列图案中是轴对称图形的是 ( )
a.(1)、(2) b.(1)、(3) c.(1)、(4) d.(2)、(3)
2.在3.14、、、、、0.020002这六个数中，无理数有 ( )
a.1个 b.2个 c.3个 d.4个
3.已知点p在第四象限，且到x轴的距离为3，到y轴的距离为2，则点p的坐标为( )
a.(-2，3) b.(2，-3) c.(3，-2) d.(-3，2)
4. 已知正比例函数y=kx (k≠0)的函数值y随x的增大而减小，则一次函数y=x k的图象大致是下列选项中的 ( )
5.根据下列已知条件，能唯一画出△abc的是( )
a.ab=5，bc=3，ac=8 b.ab=4，bc=3，∠a=30°
c.∠a=60°，∠b=45°，ab=4 d.∠c=90°，ab=6
6.已知等腰三角形的一个内角等于50，则该三角形的一个底角的余角是( )
a.25 b.40或30 c.25或40 d.50
7.若等腰三角形的周长是100cm，则能反映这个等腰三角形的腰长y(cm)与底边长x(cm)之间的函数关系式的图象是( )
a b c d
8.设0
a. b. c.k d.
9.下列命题①如果a、b、c为一组勾股数，那么3a、4b、5c仍是勾股数;②含有30°角的直角三角形的三边长之比是3∶4∶5;③如果一个三角形的三边是 ， ， ，那么此三角形
必是直角三角形;④一个等腰直角三角形的三边是a、b、c，(c >a = b)，那么a2∶b2∶c2=1∶1∶2;⑤无限小数是无理数。其中正确的个数是 ( )
a.1个 b.2个 c.3个 d.4个
10.如图所示，函数y1=|x|和y2= x 的图象相交于(-1,1)，(2，2)
两点，当y1>y2时，x的取值范围是( )
a.x<-1 b.-1
c.x>2 d.x<-1或x>2
二、填空题 (每空3分，共24分)
11. =_________ 。
12. =_________ 。
13.若△abc≌△def，且△abc的周长为12，若ab=3，ef=4，则ac= 。
14.函数 中自变量x的取值范围是_____ 。
15.如图所示，在△abc中，ab=ac=8cm，过腰ab的中点d作ab的垂线，
交另一腰ac于e，连接be，若△bce的周长是14cm,则bc= 。
第15题 第17题 第18题
16.点p(3,-5)关于 轴对称的点的坐标为 .
17.如图已知△abc中，ab=17，ac=10，bc边上的高ad=8.则△abc的周长为__________。
18.如图，a(0，2)，m(3，2)，n(4，4).动点p从点a出发，沿y轴以每秒1个单位长的速度向上移动，且过点p的直线l：y=-x b也随之移动，设移动时间为t秒. 若点m，n位于直线l的异侧，则t的取值范围是 。
三、解答题(本大题共9题，共96分)
19.计算(每题5分，共10分)
(1) (2)
20.(8分)如图，在δabc与δdef中，如果ab=de，
be=cf，只要加上 条件(写一
个就可以)，就可证明δabc≌δdef;并用你所选
择的条件加以证明。
21.(10分)如图，已知△abe，ab、ae边上的垂直平分线
m1、m2交be分别于点c、d，且bc=cd=de
(1) 判断△acd的形状，并说理;
(2) 求∠∠bae的度数.
22.(10分)如图，在平面直角坐标系中, 、均在边长为1的正方形网格格点上.
(1) 在网格的格点中，找一点c，使△abc是直角三角形，且三边长均为无理数
(只画出一个，并涂上阴影);
(2) 若点p在图中所给网格中的格点上，△apb是等腰三角形，
满足条件的点p共有 个;
(3) 若将线段ab绕点a顺时针旋转90°，写出旋转后点b的坐标
23.(10分) 我市运动会要隆重开幕，根据大会组委会安排，某校接受了开幕式大型团体操表演任务.为此，学校需要采购一批演出服装，a、b两家制衣公司都愿成为这批服装的供应商.经了解：两家公司生产的这款演出服装的质量和单价都相同，即男装每套120元，女装每套100元.经洽谈协商：a公司给出的优惠条件是，全部服装按单价打七折，但校方需承担2200元的运费;b公司的优惠条件是男女装均按每套100元打八折，公司承担运费.另外根据大会组委会要求，参加演出的女生人数应是男生人数的2倍少100人，如果设参加演出的男生有x人.
(1) 分别写出学校购买a、b两公司服装所付的总费用y1(元)
初二数学期末测试题
一．选择题(每小题3分，共30分)
1、一个三角形的两边长分别为3cm和7cm，则此三角形的第三边的长可能是
a.3cm b.4cm c.7cm d.11cm
2、下列运算中，正确的是。
a.aa2=a2 b.(a2)2=a4
c.a2a3=a6 d.(a2b)3=a2b3
3、已知点a，d，c，f在同一条直线上，ab=de，bc=ef，要使△abc≌△def，还需要添加一个条件是()
a.∠bca=∠fb.∠b=∠e
c.bc∥efd.∠a=∠edf
4、下列各式由左边到右边的变形中，是分解因式的为（）。
a、a(x y)=ax ay b、x2－4x 4=x(x－4) 4
c、10x2－5x=5x(2x－1) d、x2－16 3x=(x－4)(x 4) 3x
5．下列命题中，假命题是（）
a．9的算术平方根是3 b．的平方根是±2
c．27的立方根是±3 d．立方根等于﹣1的实数是﹣1
6、下列命题中，假命题是（）
a．垂直于同一条直线的两直线平行
b．已知直线a、b、c，若a⊥b，a∥c，则b⊥c
c．互补的角是邻补角
d．邻补角是互补的角
7、△abc中边ab的垂直平分线分别交bc、ab于点d、e，ae=3cm，△adc的周长为9cm，则△abc的周长是（）
8、使分式有意义的x的取值是()
a.x≠0b.x≠±3
c.x≠-3d.x≠3
9、点m（3，－4）关于x轴的对称点的坐标是（）
a.（3，4）b.（－3，－4）
c.（－3，4）d.（－4，3）
10、点p的坐标为（2﹣a，3a 6），且到两坐标轴的距离相等，则点p的坐标为（）
a．（3，3）b．（3，﹣3）c．（6，﹣6）d．（3，3）或（6，﹣6）
二．填空题(每小题4分，共32分)
11、五边形的内角和是.
12、一个汽车牌在水中的倒影为，则该车牌照号码
是____________。
13.已知x＋y＝1，则＝。
14、分解因式：2a2－4a=.
15、若等腰三角形腰上的高是腰长的一半，则这个等腰三角形的底角是。
16、微电子技术的不断进步，使半导体材料的精细加工尺寸大幅度缩小.某种电子元件的面积大约为0.0000007mm2，用科学记数法表示为mm2.
17、多项式加上一个单项式后，使它能成为一个整式的完全平方，那么加上的单项式可以是___________。（填上一个你认为正确的即可）
18．若点a（m，5）与点b（2，n）关于原点对称，则3m 2n的值为____．
三、简答题：（共8大题，共88分）
19、计算与化简求值（1、2小题各5分，3小题8分，共18分）
（1）(2)[(x＋y)2－(x－y)2]÷(-2xy)．
（3）先化简，再求值:（），其中x2﹣4=0．
20.分解因式(每题6分，共12分)
21、已知a，b，c三数的平均数是4，且a，b，c，d四个数的平均数是5，则d的值为（）
24、（10分）甲，乙两人准备整理一批新到的试验器材，若甲单独整理需要40分钟完工，甲、乙共同整理20分钟，乙再需单独整理20分钟才能完工。
（1）乙单独整理这批试验器材需多少分钟完工？
（2）若乙因工作的需要，他整理的时间不超过30分钟，则甲至少整理多少分钟才能完工？
25、（12分）请仔细观察表中数据，并回答下列问题。
边数34567…n
从一个顶点出发的对角线的条数01234
上述对角线分成的三角形个数02345…
总的对角线条数025914…
（1）用含n的'式子分别表示从一个顶点出发的对角线的条数，上述对角线分成的三角形个数，总的对角线条数。答案直接写在表格中。
（2）若一个多边形的总对角线数为54条，求该多边形的边数和以及内角和度数
26、（12分）观察下列等式
12×231=132×2113×341=143×3123×352=253×32
34×473=374×4362×286=682×26......
以上每个等式中两边数字是分别对称的，且每个等式中组成的两位数与三位数的数字之间具有相同规律，我们称这类等式为“数字对称等式”。
（1）根据上述各式反映的规律填空，使式子成为“数字对称等式”
①52×=×25
②×396=693×
（2）设这类等式左边两位数的十位数字为a，个位数字为b，且2≤a b≤9，写出表示“数字对称等式”一般规律的式子（含a、b），并证明。
初二第一学期数学第一单元测试题答案解析
一、选择题：
题号12345678910
答案dbaacdabcd
二、填空：
题号111213141516
答案bc=ef或be=cf或
∠a=∠d15°三角形的
稳定性5460°
三、解答题
17、证明：在△abc和△dbc中：
∴△abc≌△dcb(sss)
18、解：de=ab
理由∵∠1=∠2
∴∠1 ∠ace=∠2 ∠ace
∴∠acb=∠dce
在△abc和△dbc中：
∴△abc≌△dcb(sas)
19.证明：
∴∠b=∠e
∴∠1=∠2
∴∠3=∠4
∴bf-cf=ce-cf
∴bc=ef
在△abc和△dbc中：
∴△abc≌△dcb(sas)
20.
(1)作直线pq，在直线pq上任取一点d，作dm⊥pq;
(2)在dm上截取线段da=h;
(3)以a为圆心，以b为半径画弧交射线dp于b;
(4)以b为圆心，以a为半径画弧，分别交射线bp和射线bq于和;
(5)连结、，则△(或△)都是所求作的三角形.
第一学期期末测试题
第一学期期末测试题学校______班级______姓名______成绩______
第一部分 听力（20分）
i．根据录音选择你听到的单词。每题读两遍。（共5小题，每小题1分）
1．a． mind b． kind c． find d． mend
2．a． rest b． first c． next d． best
3．a．thirty b．three c． thirteen d．third
4．a．date b．late c．take d．cake
5．a．ted b． tod c． ed d． mat
ⅱ．根据录音中的问题选择正确的答语。每题读两遍。（共5小题，每小题1分）
6．a． why not. b． not at all. it was a pleasure.
c． yes, please! d．nice to meet you.
7．a. it's a pleasure. b． i think so.
c． i've no idea. d．don't worry.
8．a．oh, we don't. b． oh, we haven't.
c． oh, i hope so. d．oh, is it?
9．a．so i do. b． so i am.
c． so do i. d． so am i.
10．a．why not? b． here you are.
c． what is it? d．thank you very much.
ⅲ．根据录音中的对话和问题，选择正确的答语。对话和每个问题将读两遍（共5小题，每小题1分）
11．they are talking about ______.
a． the animal b．their work
c．their classmates d． time.
12．a．9:00 b．8:45 c．8:30 d．9:15
13．a．in the morning b．in the afternoon
c．in the evening d． on sunday
14．they are talking about how to ______.
a．fly a kite b．make a kite
c． climb a tree d． get the kite down
15．a． he's a student. b．he's at school.
c．he's not ill now. d． he's very ill.
ⅳ．听写
根据录音内容，填上所缺的单词。读两遍。（共10空，每空0．5分）
one morning mr green is driving 16 the country and 17 for a small bookshop. when he sees an old man 18 the side of the road, he stops his car and 19 to the old man,“i want to 20 to the sun bookshop. do you know it? ”
“yes,”the old man answered. “i 21 you the way. ”mr green 24 his car, and they drive about twelve miles (英里). 23 they come to a small house, the old man says,“stop here. ” mr green stops and 24 the house. “but this isn't a 25,” he says to the old man.
第二部分 笔试（80分）
ⅴ．语音（共5小题，每小题1分）
从下列各组中选出划线部分读音不同的`那个词。
26．a．round b．out c．touch d．blouse
27．a．health b．mean c．reach d．cleaner
28．a．passage b．gate c．orange d．village
29．a．box b．next c．example d．text
30．a．quarter b．arm c．part d．march
ⅵ．选择填空（共20题，每小题1分）
a）从下列各题所给的四个选项中选择正确的一项。
31．----__________________?
----it's november the second.
a．what's the date today
b．what time is it
c．what day is it today
d．what's the weather like
32． it's good for you to do ______every day.
a． eyes exercise b． eye exercises
c． the eye exercise d． eyes exercises
33．----does lucy teach you english?
----________________________.
a．yes, i do b． no, she isn't
c． yes, she is d．yes, she does
34．----is the big truck carrying______ ladders than the small one?
----yes, it is.
a． many
b． much
c．more more
d．much more
35．jim is______ than lucy.
a．young
b．younger
c．youngest
d．the youngest
36．----may i______ your ticket, please?
----certainly. here it is.
a．look
b．see
c． watch
d． find
37．----did you go to school every day?
----by bike.
a． what
b． why
c． how
d． where
38．----shall we go out for a walk?
----______________.
a． yes, you shall
b． yes, please
c． yes, you do
d． no, you don't
39．----how are you this morning?
----____________.
a．i'm fine, thank you
b． all right
c． i'm li ming
d． how are you
40．______ is the colour tv set?
a．how long b． how much
c． how many d． how often
41．----how does miss gao come to the factory?
----_________________.
a． by bus b． at seven
c．ten minutes d．five kilometres.
42． we often sing some english songs ______.
a． on our way home
b． on our way to home
c． on ours way to home
d．on our way school
43．----were they away yesterday?
----_____________________.
a． yes, they're b． yes, they were
c． no, they were d．no, their weren't
44． which is _______, the post office, the station or the hospital?
a． big
b．bigger
c．bigger
d． the brggest
45． tianjin shoe shop is quite near. it's only _______kilometres.
a．few
b．a few
c．a little
d．little
46． they are going to _______ this afternoon.
a． have swims b．have a swim
c． having swim d． having the swim
47．----where was jim the day before yesterday?
----he was _______home. he was ill_______ bed.
a． in; on b． in; in
c．at; on d．at; in
48．please_______ it in english.
a． speak
b．talk
c． say
d． tell
49．it's 7:20 in the morning. it's time _______to school.
a．to go
b．go
c．going
d．went
50．they had four classes yesterday morning, _______?
a． hadn't they b． didn't they
c． had they d． did they
ⅶ．根据句子的意思用适当的词填空。（共5小题，每小题1分）
51．the students _______the eraser from one to another now.
52．my shoes are broken. will you _______me yours?
53．the boy is climbing up the tree to _______the birds there.
54．we often_______ books from the library.
55．we must_______ our classroom clean.
ⅷ．改写句子（共5小题，每小题1分）
根据各小题中a句的意思，完成b句。（每空只填一词）
56．a．i am free this afternoon.
b．i have much _______this afternoon.
57．a． he is a doctor.
b．_______ is he?
58．a． a town is big. a village is small.
b．a town is bigger_______ a village.
59． a． she likes office work very much.
b．_______does she like office work?
60．a． i don't know what to do next.
b．i have no_______ what to do next.
ⅸ．用所给动词的适当形式填空。（共10小题，每小题0．5分）
61．look at the picture. the students_______(work) hard.
62．li lei_______(lift) a basket of rice on to the truck.
63．good morning, jim! nice_______(meet)you!
64．let's_______(get) off the bus, liu wei.
65． some apples are too high. it's hard for me_______ (reach)them.
66．she_______(go) to school every day.
67．i_______(not listen) to the radio every day
68．i_______ born in shanghai in 1978.
69．―did you have a good time last night? ―yes, i_______(enjoy)myself very much.
70．would you like_______(have) a cup of coffee?
ⅹ．口语应用（共5小题，每小题1分）
从右边方框中选择恰当的句子完成对话，每个句子只能使用一次。
a：hi, han meimei!
b：hi, peter.
a： 71
b：nice to see you, too! 72
a：oh, yes. it's saturday.
b：that's right. 73 we chinese often eat moon cakes on that day.
a：what? mooncakes? 74
b：don't you know? mooncake is a cake round like the moon.
a：oh, i see. are they delicious?
b：yes, it is. 75
a：yes, please! oh, it's very nice. thank you very much.
b：you're welcome. goodbye!
a：goodbye!
a．would you like to have some?
b．nice to see you!
c． how comes the word“moon cakes”?
d．and it's mid autumn day, too.
e．do you know what day it is today?
xi．完形填空（共15小题，每小题1分）
a schoolboy wanted to ask for two days off, 76 he had only learnt the phrase(短语)“have a day off”. he 77 ,then he had 78 . “mother is ill. may i have a day off, 79 ? ”he asked the teachef. “of course, you can,”replied the teacher 80 .
after a while, the boy came to 81 at the teacher's door. “may i have a day off 82 ? ” the teacher was very 83 ,“didn't you say it just now? ”
“yes, sir. but i can't be here 84 , either. ”the teacher 85 him and could not help 86 . then he said with a smile,“ 87 didn't you say‘ 88 i have two days off? ’”
the boy answered quickly 89 a loud voice. “but you only 90 us ‘have a day off’! ”
76．a．but b．and c．or d．for
77．a．thought hardly b．thought hard and hard
c．hard thought d．thought and thought
78． a．a problem b． a way c． an idea d． a phrase
79．a．miss, b．sir c．teacher d．mr
80．a．at first b．at lastly c．at once d．at all
81．a．strike b．best c．hit d．knock
82．a．too b．again c．also d．once
83．a．surprised b．excited c．afraid d．worried
84．a．tomorrow b．the day after tomorrow
c．yesterday d．the day before yesterday
85．a．heard b．understood
c．learned d．knew
86．a．laugh b．to laugh c．laughed d．laughing
87．a． why b． how c． when d． where
88．a．must b．need c．should d．may
89．a． on b． with c． in d． by
90．a．teach b．taught
c．were teaching d．are teaching
ⅶ．阅读理解（共10小题，每小题2分）
阅读下面短文，选择最佳答案。
it was a saturday morning in may. when mrs green opened her curtains(窗帘) and looked out, she said,“it's going to be a beautiful day. ” she said to her son(儿子),“get up, tom. we are going to the zoo(动物园)today. wash your hands and face. we are going to new york(纽约) by train,”
tom was six years old. he was very happy now, because he liked going to the zoo very much. he also liked going by train. he said,“i dreamed(做梦) about the zoo last night, mum. ”
“and what did you do in the zoo in your dream? ”
tom laughed(大笑) and answered,“you know, mum!
you were there in my dream too. ”
91． it was a saturday morning ______.
a． may b． march
c． in may d．in march
92．they were going to ______.
a．the zoo b． the park
c．the street d． the school
93．they were going to new york ______.
a． be bike b． by bus
c． by train d． by plane
94．tom was ______.
a．five
b．six
c．seven
d．eight
95．tom was very happy ______ he liked going to the zoo very much.
a．but
b．so
c．when
d．because
ⅷ．书面表达（共10分）
betty和bob要去邮局，按图写出他们应该怎么走。
第一学期期末测试题
第一学期期末测试题学校____ 班级____ 姓名____ 成绩____
第一部分 听力（20分）
ⅰ．将你听到的字母的序号写在题前的括号内（5分）
（ ）1．a．d t b．b t c．p t
（ ）2．a．n m b．m n c．l n
（ ）3．a．s x b．x s c．s l
（ ）4．a．g j b．j g c．j k
（ ）5．a．q u b．u q c．w q
ⅱ．将你听到的`单词或数字的序号写在题前的括号内（5分）
（ ）6．a．383838 b．338833 c．333888
（ ）7．a．class b．glass c．glasses
（ ）8．a．football b．volleyball c．basketball
（ ）9．a．100156 b．101056 c．100516
（ ）10．a．you b．yours c．your
ⅲ．根据你听到的问话，选择正确的答案，将序号写在题前的括号内（5分）
（ ）11．a．yes, it is. b．yes, there is.
c．yes, i can.
（ ）12．a．he works in a factory.
b．he has supper at seven.
c．he often watches tv at home.
（ ）13．a．i want a cup of te
b．i'm from tianjin.
c．i can speak english.
（ ）14．a．i'm fine, thanks. and you?
b．not at all.
c．here it is.
（ ）15．a．yes, she does.
b．no, she doesn't.
c．yes, he does.
ⅳ．听后完成下列文章（5分）
this is a picture 16 the bedroom. it is not 17 . the twins live here（双胞胎住在这）. there is a 18 on the floor. their shoes are under the desk. their trousers 19 on the bed. where're they? now it's nine thirty. they are 20 school now.
第二部分 笔试（80分）
ⅴ．单词辨音（2.5分）
从四个单词中，找出划线部分发音不同的：
21．a．name b．have c．game d．cake
22．a．go b．so c．do d．no
23．a．pear b．wear c．bear d．near
24．a．bowl b．grow c．yellow d．down
25．a．heavy b．ready c．speak d．bread
ⅵ．单词拼写（2.5分）
从a，b，c，d四个选项中，找出正确的拼写形式：
26． zer __
a．e b．a c．u d．o
27．d___ty
a．e b．a c．u d．i
28．n __ber
a．am b．em c．un d．um
29．j __p
a．ee b．ie c．ea d．ii
30．bl __se
a．au b．ou c．uo d．ao
ⅶ．词形转换（10分）
根据括号中的要求，写出下列单词的相应形式：
31．man（复数）____ 32．new（反义词）____
33．box（复数）____ 34．white（反义词）____
35．women（单数）____ 36．know（同音词）____
37．these（单数）____ 38．stand up（反义词）____
39．that is（缩写）____ 40．come（反义词）____
ⅷ．选择填空（20分）
41．the man is ____father.
a．kate b．kate's
c．she's d．kate's
42．how old ____?
a．are you mother b．are your mother
c．your mother is d．is your mother
43．---- who's that girl?
---- she's ____.
a．my sister b．ten
c．in red d．nice
44．i go to bed____9：15 in the evening.
a．in b．at
c．under d．on
45．tom is ____english boy. he's in ____class four, grade three.
a．an; the b．an; ×
c．a; × d．×; ×
46．let me ____it.
a．to do b．do
c．do to d．do the
47．---- is this box heavy or light? --____.
a．yes, it is b．no, it isn't
c．it's light. d．yes, it's heavy
48．---- what colour is that hat?
--____.
a．that's blue. b．it's a blue
c．it's blue d．its blue
49．hello, jim! nice____ you!
a．see b．seeing
c．sees d．to see
50．____ turn is it now?
a．who's b．whose
c．who d．whom
51．the man ____the bike is our teacher.
a．at b．in
c．on d．by
52．i am ____.
a．an chinese b．chinese
c．the chinese d．one chinese
53．---- ____is your father?
---- he is all right.
a．how b．what
c．where d．who
54．---- are you a student?
---- ____.
a．yes, i am b．no, you aren't
c．yes, you are d．yes, i'm
55．please look ____the picture on the wall.
a．in b．at
c．to d．on
56．---- hello. here is your pencil-box. ____very much.
---- ____.
a．thank; that's right
b．thank you; that's all
c．thank you; you're welcome
d．thank you; no, no
57．---- have you any sisters?
---- ____.
a．yes, i have b．no, haven't
c．yes, i've d．have
58．---- ____that girl?
---- she's my sister.
a．where's b．which is
c．who's d．whose
59．---- ____are we?
---- we're in hubei.
a．what b．who
c．where d．how
60．---- ____?
---- how do you do?
a．how do you do
b．how are you
c．what's your name, please
d．how old are you
ⅸ．按要求改写句子（10分）
61．there's some milk in the glass.（变否定句）
________________________
62．sometimes he goes shopping with his mother（就划线部分提问）
_________________________
63．they have lunch in the middle of the day. （就划线部分提问）
_________________________
64．mr white is about thirty.（就划线部分提问）
_________________________
65．he carries one frisby in his hand. （变复数句子）
_________________________
ⅹ．连词成句（5分）
66．jeep, green, is, their（.）
_________________________
67．am, in, i, not, two, class（.）
_________________________
68．his, are, these, pictures（.）
_________________________
69．colour, dress, is, kate's, what（?）
_________________________
70．that, is, who, old, woman（?）
_________________________
ⅺ．选择适当的词，填在相应的空处（10分）
now look 71 the picture. the farm in the picture is in the 72 . it is not cold today. the sun is in the sky. there's a farm-house near the river. there are many tall trees 73 the farm-house. in the field there are some small trees. they are some apple trees. there are a lot of apples 74 them. there are many 75 on the farm. they are horses, cows, 76 , and pigs. the man near the gate （门口） is the 77 . a woman is feeding the chickens. this is the 78 wife. （妻子）
they have two children. one is a boy. the other is a girl. they are 79 school. they study hard.
it's a happy 80 , isn't it?
71．a．in b．at c．for d．with
72．a．country b．farm c．city d．town
73．a．in front b．in c．in front of d．at
74．a．at b．from c．on d．in
75．a．animals b．pigs c．people d．cats
76．a．a sheep b．sheeps c．sheep d．sheep's
77．a．farmer b．writer c．driver d．teacher
78．a．his b．farmer's c．farmer d．farmers
79．a．go to b．for c．at d．with
80．a．house b．family c．home d．room
ⅻ．阅读理解（10分）
选择正确的答案，完成句子
look! it's a picture of a family. there is a white house in the picture. behind the house, there are some tall trees. in front of it, there are some flowers. there is a little child in front of the house. she's about eight. she is a schoolgirl. she doesn't go to school today. she is watering some flowers. she loves flowers. she does it every day. a man and a woman are near the house. they are the girl's father and mother. the man is mending a bike. he is a worker. he doesn't go to his factory today, too. the woman is reading a newspaper. she is an english teacher. she speaks english very well. she is in the same school with her daughter. to day is sunday. they are all at home. this is a very good family.
（ ）81．the house is in the ____.
a．country b．city c．picture
（ ）82．near the house there are some ____.
a．trees b．trees and flowers c．flowers
（ ）83．all the people in the picture are ____.
a．free b．working c．studying
（ ）84．the father goes to work ____.
a．by plane b．on foot c．by bike
（ ）85．it is a____ family.
a．happy b．interesting c．kind
ⅹⅲ．补全对话（10分）
86．a：how are you?
b：fine, ____and you?
a：i'm ____, too.
87．a：excuse me! are you liu wei?
b：sorry, i am ____.
88．a：____ that over there?
b：it's a green bike.
a：is it yours?
b：no, ____.
89．a：are you in?
b：i'm ____class four.
90．a：whose shirt is this? is it ____, jim?
b：no, it isn't. mine ____green, and this one is yellow.
91．a：excuse me, ____that boy?
b：which one?
a：the one under the tree.
b：oh, ____my friend, li lei.
第一学期期末测试题
第一学期期末测试题笔试部分（60％）
ⅰ．语音。找出每组划线部分的读音与其它三个不同的'词（10％）
( )1．a．bell b．lesson c．metre d．second
( )2．a．hand b．animal c．happy d．many
( )3．a．truck b．month c．june d．nothing
( )4．a．term b．turn c．short d．word
( )5．a．post b．watch c．stop d．hospital
( )6．a．hard b．quarter c．class d．half
( )7．a．side b．night c．july d．city
( )8．a．shall b．machine c．chicken d．sure
( )9．a．third b．tooth c．than d．think
( )10．a．begin b．orange c．glass d．green
ⅱ．选择划线部分的正确释义（5％）
( ) 1．you'd better catch a bus.
a．等公共汽车
b．赶公共汽车
c．乘坐小汽车
( ) 2．walk along the road, and take the first turning on the left.
a．在左边
b．在一边
c．在旁边
( )3．i like to keep busy.
a．不紧不慢
b．保存东西
c．保持忙碌，紧张
( ) 4．are you enjoying living in china?
a．住在中国
b．在中国工作
c．在中国学习
( ) 5．i think february is worse than january.
a．比一月份好
b．比一月份糟
c．和一月份一样
ⅲ．选择填空（15％）
( )1．shanghai is a big city. suzhou is a small city.
shanghai is ______ than suzhou.
a．small b．smaller
c．big d．bigger
( ) 2．the fifth month of the year is ______.
a．february b．may
c．april d．august
( )3．a： how do you usually come ______ school?
b： i usually come ______ bus.
a．at, in b．to, with
c．to, by d．by, to
( )4．a： ______ your mother work in a post office?
b： yes, she ______.
a．do, do b．is, is
c．are, are d．does, does
( ) 5．a： where ______ you meet him yesterday?
b： i ______ him in front of the station.
a．do, meet b．were, met
c．did, meet d．did, met
( )6．a： are you free tomorrow?
b： no. i ______ see my grandma with my mother.
a．be going to b．am going to
c．going to d．am not going to
( )7．a：______ you at home last night?
b： no, i ______.
a．were, were not b．were, wasn't
c．did, didn't d．are, am not
( ) 8．a： ______ is that meat, please?
b： four yuan a kilo.
a．how much b．how many
c．how often d．how long
( ) 9．a： what are we going to do next week?
b： nothing ______. why?
a．many b．a lot
c．much d．all
( )10．i think it's time ______ class.
a．for b．in
c．to d．go
( )11．a： when shall we meet?
b： let's ______ it a quarter to three.
a．do b．make
c．have d．see
( )12．i think i can ______ tomorrow.
a．am free b．free
c．going to be free d．be free
( ) 13．who has ______ apples, li lei, jim or lucy?
a．much b．most
c．the most d．more
( )14．we can see ______ sun in the day-time.
a．a b．the
c．an d．some
( ) 15．this ruler is ______ short. do you have a long one?
a．two b．to
c．too d．not
ⅳ．连词成句（5％）
1．was, jim, born, not, oxford, in
______________?
2．there, long, you, did, how, stay?
______________?
3．day, tomorrow, what, it, is?
______________?
4．school, to, he, went, bike, by
______________?
5．no time, breakfast, he, for, had
______________?
ⅴ．补全对话（每空一词）（15％）
（1） a： excuse me. where ______ the nearest hospital, please?
b： walk ______ this road, and take the second turning ______ the left. it's about 50 metres along on the right.
a： thank you.
b： you're welcome.
（2） a： what ______ ______ ______ today?
b： it's saturday.
a： ______ day was it ______?
b： it was friday.
（3）a： hello, bill! may i ______ some questions?
b： certainly!
a： ______ were you born?
b： i was born ______ january lst, 1978.
a： ______ were you born?
b： i was born ______ england.
a： ______ did you come to china?
b： because my father and mother wanted to work in china.
a： do you enjoy living in china?
b： yes, very ______.
ⅵ．阅读短文，然后做下列练习（10％）
mark twain（马克・吐温）was an american writer（作家）. one day he went to a city by train. he wanted to see one of his friends there. he was a very busy man. he usually forgot something.
when he was in the train, the conductor（列车员）asked him for his ticket. mark twain looked for the ticket here and there, but he couldn't find it. the conductor knew mark twain. she said,“show me your ticket on your way back. and if（如果）you can't find it,it doesn't matter.”
“oh, but it does,”said mark twain.“i must find the ticket. if i can't find it, how can i know where i'm going?”
a．根据短文判断下列句子的正（√）误（×）（5％）
( ) 1．mark twain usually forgot something because he was very busy.
( ) 2．mark twain did not want to show his ticket to the conductor.
( ) 3．the conductor didn't know mark twain.
( ) 4．the conductor said mark twain could show his ticket on his way back.
( ) 5．mark twain couldn't find his ticket, so he bought another one.
b．选择正确答案（5％）
( ) 1．mark twain was a ______.
a．teacher b．student
c．doctor d．writer
( ) 2．mark twain went to the city
a．by plane b．by car
c．by train d．by bus
( ) 3．mark twain went to the city to ______.
a．see his friend b．buy some paper
c．sell his books d．see his parents
( ) 4．when he was in the train, the conductor asked him for ______.
a．some books b．the ticket
c．a pen d．some food
( )5．mark twain didn't show his ticket because he could not ______ it.
a．buy b．find
c．look for d．know
听力部分（20％）
ⅰ．听对话，选择正确答案（5％）
1．a．she is fourteen. b．she is twelve.
c．she is eleven. d．she is fifteen.
2．a．the apples b．the pears.
c．the oranges. d．the bananas.
3．a．it's over the car. b．it's behind the car.
c．it's inside the car d．it's behind the tree.
4．a．at 6∶30 b．at 8∶30.
c．at 7∶00. d．at 7∶30.
5．a．noodles, milk and eggs. b．porridge, milk and bread.
c．bread, eggs and milk. d．fish, eggs and rice.
ⅱ．听短文，回答问题（5％）
1．where is the big tree?
a．near the river b．in the river.
c．near the house. d．near the school.
2．what are the boys diong?
a．they are reading books. b．they are swimming.
c．they are boating. d．they're playing football.
3．what are there in the tree?
a．some birds. b．some boys.
c．some dogs. d．some cats.
4．who is going to climb the tree?
a．a boy. b．a cat.
c．a dog. d．a bird.
5．what colour is the dog?
a．white. b．black.
c．brown. d．yellow.
ⅲ．听写填空（10％）
tom is an ______ teacher. he is ______ in china. he lives in a ______ building in the ______ of the city. there are ______ floors in his building. he lives ______ the twelfth floor. he ______ walks up and down. he ______to work by ______ every day. he ______ very strong.
口试部分（20％）
ⅰ．教师准备若干对话，学生两人一组抽签。给予一定的准备时间，然后两人表演。表演时不能看对话（10％）
下面的对话供参考：
1．a： what are you going to do tomorrow?
b： i've no idea. what do you think?
a： shall we go to the zoo?
b： good idea! when shall we meet?
a： what about a quarter past nine?
b： that's ok. see you then.
2．a： excuse me. is there a post office near here?
b： no, there isn't. the nearest one is about 3 kilometres away. you'd better catch a bus.
a： which bus do i take, please?
b： i take bus no. 15. the bus stop is over there in front of the tall building.
a： thank you very much.
b： you're welcome.
ⅱ．教师准备若干难易相当的短文，学生抽读。快速阅读后，口头回答教师的问题（10％）
下面的短文供参考：
li hai had a busy and happy day last sunday. he got up at 7∶30 in the morning. after breakfast he began to wash his clothes. after he finished the washing, he began to do his english homework. in the afternoon he mended his mother's bike. at about five o'clock he helped his mother cook supper. he watched tv for some time after supper. then he went to bed at about 10 o'clock.
1．when did li hai get up last sunday morning?
2．what did li hai do after he finished washing his clothes?
3．what did he do last sunday afternoon?
4．when did he help his mother cook supper?
5．did he go out last sunday?
数学初二第一单元测试题
练习：
1、三角形的三边长分别是4、7、x，则x的取值范围是它的周长的取值范围是
2、已知等腰三角形的两边长分别是4cm和5cm，则它的周长是，若它的`两边长分别是4cm和9cm，则它的周长是。
3、有5条线段分别长为1cm、2cm、3cm、4cm、5cm，则以其中3条线段为边可以构成个三角形。
4、在下面三个三角形中分别画出它的三条高、三条中线、三条角平分线，并写出图中相等的线段或角。
5、要使一个五边形具有稳定性，则需至少添加条对角线。
6、已知直角三角形的三边长为3cm、4cm、5cm，那么它的斜边上的高
为cm。
11.2与三角形有关的角
三角形内角和定理：
推论：1、直角三角形的;
2、有三角形是直角三角形;
3、三角形的外角等于。
练习：
1、三角形至少有个锐角，至少有个锐角小于60°
2、等腰三角形的一个角为40°，则它的另外两个角为
3、等腰三角形的一个角为140°，则它的另外两个角为
4、δabc中，∠b=∠a 20°，∠c=∠b 50°，求δabc的各内角的度数。
5、如图，∠b=42°，∠a 10°=∠1,∠acd=64°证明：ab∥cd
6、如图，ab∥cd，∠b=72°，∠d=32°，求∠f的度数。
为大家推荐的数学初二第一单元测试题，大家一定要仔细阅读哦，祝大家学习进步。
初二数学下册期末测试题
解答题(本题共30分，第17题5分，第18～20题每小题6分，第21题7分)
17.解：.
，，.…………………………………………………………1分
.……………………………………………2分
方程有两个不相等的实数根…………………………3分
.
所以原方程的根为，.(各1分)………………5分
18.解：(1)∵一次函数的图象与y轴的交点为a，
∴点a的坐标为.…………………………………………………1分
∴.…………………………………………………………………2分
∵，
∴.…………………………………………………………………3分
∵一次函数的图象与x轴正半轴的交点为b，
八年级是一个至关重要的学年，大家一定认真复习，接下来看看为大家推荐的八年级下册数学期末试题(苏教版)，会有很大的收获哦!
一、选择题(单项选择，每小题3分，共21分).
1.要使分式有意义，必须满足的条件是.
a.b.c.d.
2.下列代数式中，是分式的是()
a.b.c.d.
3.在平面直角坐标系中，点(2，-3)关于轴对称的点的坐标是().
a.(-2，-3)b.(2，-3)c.(-2，3)d.(2，3)
4.如果把分式中的、都扩大3倍，那么分式的值()
a.扩大3倍 b.不变 c.缩小3倍 d.缩小6倍
5.若点p()在第二象限，则的取值范围是()
a.<1b.<0c.>0d.>1
6.函数与(a≠0)在同一直角坐标系中的图象可能是()
7.如图，小亮在操场上玩，一段时间内沿m→a→b→m的路径匀速散步，能近似刻画小亮到出发点m的距离y与x之间关系的函数图象是()
二、填空题(每小题4分，共40分)
8.若分式方程有增根，则这个增根是
9.如图，反比例函数的图象经过点p，则=.
10.用科学记数法表示：0.000004= .
11.将直线向下平移4个单位得到直线，则直线的解析式为.
12.直线y=kx b与直线y=-2x 1平行，且经过点(-2,3)，则解析式为.
13.已知点q(-8，6)，它到x轴的距离是，它到y轴的距离是.
14、如图，在矩形abcd中,ab=3,ad=4,p是ad上一动点,pf⊥bd于f,pe⊥ac于e,
则pe pf的值为.
15、如图，在反比例函数的图象上，有点，，，，它们的横坐标依次为1，2，3，4，分别过这些点作轴与轴的垂线，图中所构成的阴影部分的面积从左到右依次为，，，则 =
16.14.如果菱形的两对角线分别为6和8，则它的面积是.
17.如图，矩形abcd中，ab=1，ac=2，对角线ac、bd相交于点o，直线bd绕点o逆时针旋转(0°<<120°)，交bc于点e，交ad于点f.
(1)oa= ;
(2)若四边形aecf恰好为菱形，则的值为 .
综合试卷5.30
班级姓名座号成绩
一、选择题
题目1234567
选项
二、填空题
8、9、10、11、12、
13、(1)(2)14、15、16、17、(1)(2)
三、解答题(共89分).
18.(10分)计算：(1).(2)
19、解方程(10分)(1) (2)
20.(7分)先化简，再求值：其中.
21、(9分)如图，已知反比例函数y=的图象与一次函数y=ax b的`图象交于
m(2，m)和n(-1，-4)两点.
(1)求这两个函数的解析式;(2)求△mon的面积;
(3)请判断点p(4，1)是否在这个反比例函数的图象上，并说明理由.
22.(9分)如图，菱形的对角线、相交于点，，，请说明四边形是矩形.
23.(9分)如图，在四边形abcd中，ab=cd，bf=de，ae⊥bd，cf⊥bd，垂足分别为e，f.(1)求证：△abe≌△cdf;
(2)若ac与bd交于点o，求证：ao=co.
24.(9分)如图，在梯形abcd中，ad∥bc，ab=cd，且ab
(1)直接填空：ab=;
(2)若直线ab以每秒0.5的速度向右平移，交ad于点p，交bc于点q，则当直线ab移动的时间为多少秒时，四边形abqp恰好为菱形?(精确到0.1秒)
25.(13分)如图11，矩形中，点在轴上，点在轴上，点的坐标是
(-12，16)，矩形沿直线折叠，使得点落在对角线上的点处，折痕与、轴分别交于点、.
⑴直接写出线段的长;⑵求直线解析式;
⑶若点在直线上，在轴上是否存在点，使以、、、为顶点的四边形是平行四边形?若存在，请求出一个满足条件的点的坐标;若不存在，请说明理由.
26.(13分)是等边三角形，点是射线上的一个动点(点不与点重合)，是以为边的等边三角形，过点作的平行线，分别交射线于点，连接.
(1)如图(a)所示，当点在线段上时，
①求证：;
②探究：四边形是怎样特殊的四边形?并说明理由;
(2)如图(b)所示，当点在的延长线上时，
①第(1)题中所求证和探究的两个结论是否仍然成立?(直接写出，不必说明理由)
②当点运动到什么位置时，四边形是菱形?并说明理由
为大家推荐的八年级下册数学期末试题(苏教版).还满意吗?相信大家都会仔细阅读，考出一个满意的成绩，加油哦!
∴点b的坐标为.…………………………………………………4分
(2)将的坐标代入，得.
解得.…………………………5分
∴一次函数的解析式为.
…………………………………6分
19.解：(1)按要求作图如图1所示，四边形和
四边形分别是所求作的四边形;…………………………………4分
(2)bd≥ac.……………………………………………………………6分
阅卷说明：第(1)问正确作出一个四边形得3分;第(2)问只填bd>ac或bd=ac只得1分.
20.(1)证明：如图2.
∵四边形abcd是平行四边形，
∴ab∥cd，ab=cd.……………1分
∴∠1=∠2.………………………2分
在△abe和△cdf中，
………………………3分
∴△abe≌△cdf.(sas)…………………………………………4分
∴ae=cf.……………………………………………………………5分
(2)当四边形aecf为矩形时，=2.………………………………6分
编辑老师在此也特别为朋友们编辑整理了宁城县初二数学下册期末测试题。
寒窗苦读，为的就是在考试中展现出自己最好的水平，大家更应该加把劲，努力学习，认真总结知识点，大量做题，从中找出自己的不足。详细内容请看下文苏州高新区初二数学下册期末测试题。
解答题(本题7分)
22.北京是水资源缺乏的城市，为落实水资源管理制度，促进市民节约水资源，北京市发
改委在对居民年用水量进行统计分析的基础上召开水价听证会后发布通知，从
年5月1日起北京市居民用水实行阶梯水价，将居民家庭全年用水量划分为三档，水
价分档递增，对于人口为5人(含)以下的家庭，水价标准如图1所示，图2是小明
家在未实行新水价方案时的一张水费单(注：水价由三部分组成).若执行新水价方
案后，一户3口之家应交水费为y(单位：元)，年用水量为x(单位：)，y与x
之间的函数图象如图3所示.
根据以上信息解答下列问题：
(1)由图2可知未调价时的水价为元/;
初二数学下册期末测试题
一、选择题
1.要了解全校学生 的课外作业负担情况，你认为以下抽样方法中比较合理的是( ) a.调查全体女生 b.调查全体男生
c.调查九年级全体学生 d.调查七年级，八年级，九年级各100名学生
2.为了了解某市八年级学生的肺活量，从中抽样调查了500名学生的肺活量，这项调查中的样本是( ).
a.某市八年级学生的肺活量 b.从中抽取的500名学 生的肺活量
c.从中抽取的500名学生 d.500
3. 袋子中装有4个黑球和2个白球，这些球的形状、大小、质地等完全相同，在看不到球的条件下，随机地从袋子中摸出三个球.下列事件是必然事件的是( )
a.摸出的三个球中至少有一个球是黑球.
b.摸出的三个球中至少有一个球是白球.
c.摸出的三个球中至少有两个球是黑球.
d.摸出的三个球中至少有两个球是白球.
4、下列约分，结果正确的是( )
a、b、c、d、
5、若 中的x和y都缩小一半，那么分式的值 ( )
a、缩小为原来的 b、不变 c、扩大到原来的2倍 d、扩大到原来的4倍
6、在平行四边形abcd中，对角线ac，bd相交于o，若ac=10，bd=6，则ab的长的取值范围是( ).
a、2
7. 如图.在菱形abcd中，对角线ac，bd交于点o，下列说法错误的是( )
a.ab∥dc b.ac=bd c.acbd d.oa=oc
8. 如图，矩形abcd的对角线ac、bd相交于点o，ce∥bd，de∥ac，若ac=4，则四边形code的周长( )
a. 4 b. 6 c. 8 d. 10
9. 如图，abcd是正方形，g是bc上(除端点外)的任意一点，deag于点e，bf∥de，交ag于点f.下列结论不一定成立的是
a.△aed≌△bfa b.de-bf=ef
c.af-bf=ef d.de-bg=fg
第7题图 第8题图 第9题图
10、如图，矩形abcg(ab
a.0 b.1 c.2 d.3
二、填空题
11.将一批数据分成5组，列出分布表，其中第一组与第五组的频率之和是0.27，第二与第四组的频率之 和是0.54，那么第三组的频率是 _________ .
12.某中学为了了解本校2 000名学生所需运动服尺码，在全校范围内随机抽取100名学
生进行调查，这次抽样调查的样本容量是 _________ .
13、在分式 中，当 时，分式无意义;
14、分式 、、、中，最简分式的个数是_________个。
15.分式 的最简公分母是_____ ___ _.
16、菱形的.两条对角线分别为6cm和8cm，则菱形的面积为_____cm;边长是_____cm，菱形的高是_____cm
17、平行四边形的一个内角平分线将对边分成3和5两个部分，则该平行四边形的周长是____________.
18、如图，正方形abcd中，e为bc延长 线上一点，且ce=ac，ae交dc于f， 则 afc=_______.
19、设 ， ，则 的值等于 .
20.如图，将n个边长都为1cm的正方形按如图所示摆放，点a1、a2、、an分别是正方形的中心，则n个这样的正方形重叠部分的面积和为____________ __(用n的代数式表示);