【 – 小学作文】
篇一:《2013-2014年13分八年级下学期期中数学答案》
2013–2014学年度北京市第十三中学分校 第二学期期中 八年级 数学答案
一．选择题：（每小题3分，共30分）
1．A 2．A 3．D 4．B 5．C 6．C 7．A 8．C 9．D 10．C
二．填空题：（每小题2分，共16分）
11．24/5； 12．30°； 13．1.5； 14．（1
1
； 15． x=3； 16．8； 17．3 18． -6 三．解答题
19. 过A作AD⊥BC于D，……………………………1分
在RTΔABD中，∠
D=30°，
∴∠BAD=60°，AD=1/2AB=4
，BD=√3AD=4√3，………3分
在RTΔACD中，∠CAD=105°-60°=45°，
∴CD=AD=4，………………………………………………4分 ∴BC=4√3+4。
………………………………………
.5分
20. 解 (1)∵点C(m,4)在直线y=x上,
∴4=m, 解得m=3. …………….1分
∵点A(-3,0)与C(3,4)在直线y=kx+b(k≠0)上,
∴解得
∴一次函数的解析式为y=x+2……………….3分
(2)如图,过点D1作D1E⊥y轴于点E,过点D2作D2F⊥x轴于点F,
∵点D在第二象限,△DAB是以AB为直角边的等腰直角三角形,
∴AB=BD1,AB=AD2,
∵∠D1BE+∠ABO=90°,∠ABO+∠BAO=90°,
∴∠BAO=∠D1BE.
∵在△BED1和△AOB中,
八年级 数学期中统测 第 1 页 共 13 页
∴△BED1≌△AOB(AAS),
∴BE=AO=3,D1E=BO=2,
即可得出点D的一个坐标为(-2,5),………………………5分
同理可得出:△D2FA≌△AOB,
∴FA=OB=2,D2F=AO=3,
∴点D的另一个坐标为(-5,3),…………………………….6分
综上所述:点D的坐标为(-2,5)或(-5,3).
21. 证明：∵四边形ABCD是平行四边形，
∴CD=AB，AD=CB，∠DAB=∠BCD．………………………..1分
又∵△ADE和△CBF都是等边三角形，
∴DE=BF，AE=CF．
∠DAE=∠BCF=60°．
∵∠DCF=∠BCD﹣∠BCF，
∠BAE=∠DAB﹣∠DAE，
∴∠DCF=∠BAE．………………………………………………..3分
∴△DCF≌△BAE（SAS）．
∴DF=BE．……………………………………………………………….4分
∴四边形BEDF是平行四边形．………………………………5分
22. 证明：∵AP+AB=PBPD+CD=PC
∴PA+PC=PB-AB+PD+CD
∵AB=CD
∴PA+PC=PB+PD……………………………….3分
2.当点P运动到矩形ABCD外时，结论仍然成立……………..4分
证明：作PF⊥BC,垂足为F,交AD于E,则PE⊥AD,
AP=AE+PEPD=ED+PE, PC=PF+FCPB=PF+BF
∴AP+PC=AE+PE+PF+FC, BP+DP =PF+BF+ED+PE ∵AE=BF,ED=FC ∴PA+PC=PB+PD…………………..6分
23. 作图正确并猜出四边形BGME为菱形……………………………….1分 ∵BD⊥AC，GM⊥AC
∠GMD=∠BDC=90°
∴BD‖GM，∠CGM+∠GCM=∠EGB+∠GCB=90°，………..2分
∵CE平分∠BCA
∴∠GCM=∠GCB
∵∠GBC=90°
八年级 数学期中统测 第 2 页 共 13 页
∴BG⊥BC
∴GM=GB…………………….3分
∴∠CGM=∠CGB，
∴∠CGM=∠GEB，
∴GB=BE
∴GM=BE
∴四边形GMEB是平行四边形…………………………………………….…..5分 ∴GB=GM ∴BGME为菱形…………………………………………6分
24. 解：（1）设商场计划购进空调x台，则计划购进彩电（30﹣x）台，由题意，得 y=（6100﹣5400）x+（3900﹣3500）（30﹣x）=300x+12000；…………….1分
（2）依题意，有，………….2分
解得10≤x≤12．……………………….3分
∵x为整数，
∴x=10，11，12．…………………………..4分
即商场有三种方案可供选择：
方案1：购空调10台，购彩电20台；
方案2：购空调11台，购彩电19台；
方案3：购空调12台，购彩电18台；…………………5分
（3）∵y=300x+12000，k=300＞0，
∴y随x的增大而增大，
即当x=12时，y有最大值，y最大=300×12+12000=15600元．
故选择方案3：购空调12台，购彩电18台时，商场获利最大，最大利润是15600元．………….6分
八年级 数学期中统测 第 3 页 共 13 页
25. （1）E（1,0）………………….1分
（2）（2）作点D关于x轴的对称点轴,且，作∥=2，连CG交轴于点F，此时四边形
的周长是最小的。 ————2分 ∵
∴OD={13.13分是多少点}.
∵=2 ，D为边OB的中点 =2 即（0，-2） ∴G(2，-2) ————3分 ∵矩形,,{13.13分是多少点}.
∴OB=AC=4,OA=BC=3
∴C(2,3)
设直线CG的解析式为y=kx+b
∵G（2，-2）,C(3,4)
∴y=6x-14 ————4分
当y=0时，
x=即F
（，0） ∴E
（，0）
∴当E
（，0），F
（，0
）时四边形的周长是最小的。 ————6分
26. .证明：（1）∵∠BAC=90°，∠ABC=45°，
∴∠ACB=∠ABC=45°，
∴AB=AC，
∵四边形ADEF是正方形，
∴AD=AF，∠DAF=90°，
∵∠BAD=90°﹣∠DAC，∠CAF=90°﹣∠DAC，
∴∠BAD=∠CAF，
则在△BAD和△CAF中，
八年级 数学期中统测 第 4 页 共 13 页
，
∴△BAD≌△CAF（SAS），
∴BD=CF，
∵BD+CD=BC，
∴CF+CD=BC； ……………………………………………..3分
（2）CF﹣CD=BC；……………………………………………4分
（3）①CD﹣CF=BC……………………………………………5分 ②∵∠BAC=90°，∠ABC=45°，
∴∠ACB=∠ABC=45°，
∴AB=AC，
∵四边形ADEF是正方形，
∴AD=AF，∠DAF=90°，
∵∠BAD=90°﹣∠BAF，∠CAF=90°﹣∠BAF，
∴∠BAD=∠CAF，
∵在△BAD和△CAF中，
∴△BAD≌△CAF（SAS），
∴∠ACF=∠ABD，
∵∠ABC=45°，
∴∠ABD=135°，
∴∠ACF=∠ABD=135°，
∴∠FCD=90°，
∴△FCD是直角三角形．…………………………..6分
∵正方形ADEF的边长为
2且对角线AE、DF相交于点O． ∴
DF=AD=4，O为DF中点．
∴
OC=DF=2．………………………………….7分
八年级 数学期中统测 第 5 页 共 13 页
篇二:《高考得分点基础训练 13》
高考得分点基础训练（13）
II． Grammar and Vocabulary
A
The flu season doesn’t officially start until next month, and continues until March. Yet signs touting flu shots are all over. It’s too early ___25___________ (roll) up the sleeve and get one, isn’t it? Not at all, says Dr. Derek Van Amerongen, medical director of Chicago-based Humana Vitality. Actually, the earlier the better. Now is the perfect time, because then you ward off the flu season, according to Van Amerongen. “Everyone should take the flu seriously and get the vaccine,” says Van Amerongen. “The shots are a safe, inexpensive way to prevent ___２６___ (get) sick.” And ___２７______________ (forget) those misconceptions that the shot causes the flu. “The shot contains only dead cultures of the virus,” Van Amerongen says. “It is a matter of coincidence ___２８_________ someone gets the flu after getting the shot.” Even if a person had the shot and later came down with the flu, there is an upside. “The flu shot is not perfect,” said Van Amerongen, “but it is the only ___２９___________ (prove) protection against the virus and if someone should get the flu after having the shot it will be much milder.” No new strains of the flu have surfaced this season; however, the ones that exist Dr. Van Amerongen says, “are dangerous enough.” Last year 40,000 people died from the virus. The young and elderly are ___３０________ most susceptible to get the virus and typically have the worse eases. He recommends everyone age 6 months and older ___３１_____ have the vaccine. 25_________________26.______________ 27_______________.28.______________
29.________________30._______________31._______________
B
Is social media making us smarter? You bet it is, argues a new study.
Academic newspaper Globe and Mail claims that social media—especially Twitter—is making us hyper literate. But how could our feed, ___３2_________ probably contains a mixture of fun tweets, hard news, and satirical parody accounts, actually be making us smarter? Think about it: Twitter gives us access to massive amounts of information, right at our fingertips. ___３3___ also introduces us to new words, ideas and opinions. From 1986 to 2006, the average length of a freshman’s essay ___３4__________ (increase) from 422 words to 1038 plus the essays were far more complex, and students used better evidence to support their point. ___３5_______ (scroll) your Twitter feed in your free time may seem like totally no big deal, ___３6________ maybe you should now refer to it as studying—absorbing all the information improves your writing and critical thinking skills! Plus, each time you rush to think of a witty reply ___37___ a tweet or add your commentary to an event you’re live-tweeting (like the VMAs or Grammys), it actually helps you become a better thinker, faster thinker, claims Globe and Mail. “There’s powerful evidence ___３８__________ digital tools are helping young people write and think far ___３９__________ (good) than in the past,” the article states. The Globe and Mail claim that, thanks ___4０__________ Twitter, people aren’t just consuming media they’re “talking back to it.” 32_________________33.______________ 34_______________.35.______________
36.________________37._______________38._______________39____________40.________
▲Section B (10分)
A. expressed B. specialized C. average D. specially E. proved F. vacant G. worked H. history I. hunters J. suggestion K. up
There is a new type of small advertisement becoming increasingly common in newspaper classified columns. It is sometimes placed among “situations ___4１___”, although it does not offer anyone a job, and sometimes it appears among “situations wanted”, although it is not placed by someone looking for a job either. What it does is to offer help in applying for a job. “Contact us before writing your application”, or “Make use of our long experience in preparing your job history”, is how it is usually ___4２___. The growth and success of such a(n) ___4３___ service is, of course, a reflection on the current high levels of unemployment. It is also an indication of the growing importance of job history, with the ___4４___ that it may now qualify as an art form itself.
There was a time when those job ___45___ simply wrote letters of application. “Just put down your name, address, age and whether you have passed any exams”, was about the ___4６___ level of advice offered to young people applying for their first jobs when I left school. The letter was really just for a start, it was explained, everything else could and should be saved for the interview. And in those days of full employment, the technique ___4７___. The letter proved that you could write and were available for work. Your eager face and intelligent replies did the rest.
Later, as you moved ___4８___ the ladder, something slightly more sophisticated (老练的) was called for. The advice then was to put something in the letter which would make you different from the rest. “Your search is over. I am the person you are looking for,” was a widely used trick that occasionally succeeded. Or it might be some special feature ___4９___ designed for the job in view.
There is no doubt, however, that it is the increasing number of applicants with university education that has led to the greater importance of the job ___５０___.
III． Reading Comprehension
A
Andrew Carnegie, once the world’s richest person, was born in 1835 to a weaver’s family in Scotland. As a child, he was expected to follow his father’s profession. But the industrial revolution destroyed the weavers’ craft, and the family had to leave for new possibilities in America.
In 1848 the Carnegies arrived in Pittsburgh, then the iron-manufacturing centre of the country. Young Carnegie took odd jobs at a cotton factory and later worked as a messenger boy in the telegraph office. He was often asked to deliver messages to the city theatre, where he would stay to watch plays by great playwrights. He also spent most of his leisure hours in a small library that a local benefactor (捐助者) made available to working boys.
After the Civil War, Carnegie saw great potential in the iron industry. He devoted himself to the replacement of wooden bridges with stronger iron ones and earned a fortune. He further introduced a new steel refining process to convert iron into steel. By 1900, Carnegie Steel produced more of the metal than all of Great Britain.
However, Carnegie often expressed his uneasiness with the businessman’s life. Wishing to spend more time receiving instruction and reading systematically, he once wrote, “If I were to continue much longer in the state of being overwhelmed by business cares and with most of my thoughts wholly upon the way to make more money in the shortest time, it would degrade me beyond hope of permanent recovery.” The strong desire for intellectual (智力的) pursuit led him to sell his company and retire at 64.
Fond of saying that “the man who dies rich dies disgraced,” Carnegie then turned his attention to giving away his fortune. He abhorred charity; instead, he used his money to help others help themselves. He established over 2,500 public libraries, and sponsored numerous cultural, educational and scientific institutions. By the time he died in 1919, he had given away 350 million dollars.
( ) 66. Andrew Carnegie moved to the United States because _________.
A. his father was offered a good job in Pittsburgh
B. he did not want to follow his father’s profession
C. there were serious political problems in Scotland
D. his family could not make a good living in their hometown
( ) 67. When did Carnegie begin to show his interest in artistic and intellectual pursuit?
A. After he retired from his business.
B. When he was a young boy back in Scotland.
C. After he earned his fortune from his iron business.
D. When he worked as a messenger boy in Pittsburgh.
( ) 68. Which of the following best characterizes how Carnegie managed his business?
A. He was