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一、单项选择 第1题～第800题。选择一个正确的答案，将相应的字母填入题内的括号中。
1. 用晶体管图示仪观察共发射极放大电路的输入特性时，
A、X轴作用开关置于基极电压，Y轴作用开关置于集电极电流
B、X轴作用开关置于集电极电压，Y轴作用开关置于集电极电流
C、X轴作用开关置于集电极电压，Y轴作用开关置于基极电压
D、X轴作用开关置于基极电压，Y轴作用开关置于基极电流
2. 线圈中的感应电动势大小与线圈中
A、磁通的大小成正比
B、磁通的大小成反比
C、磁通的变化率成正比
D、磁通的变化率成反比
3. JSS-4A型晶体三极管h参数测试仪中的偏流源部分有
档输出且连续可调，给被测管提供偏流。
4. 下列属于轮廓控制型数控机床是
A、数控车床
B、数控钻床
C、加工中心
D、数控镗床
5. 直流差动放大电路可以
A、放大共模信号，抑制差模信号
B、放大差模信号，抑制共模信号
C、放大差模信号和共模信号
D、抑制差模信号和共模信号
6. 寄存器主要由
C、多谐振荡器
D、触发器和门电路
7. 自动生产线按自动化程度分
大类。（自动化生产线和非自动化生产线C
A、图解分析法
B、图形分析法
C、近似估算法
D、正交分析法
9. 小型变压器的绕制时，对铁心绝缘及绕组间的绝缘，按对地电压的
倍来选用。
10. 简单逆阻型晶闸管斩波器的调制方式是
A、定频调宽
B、定宽调频
C、可以人为地选择
D、调宽调频
11. 机械设备中，轴承的常用润滑剂有
正在加载中，请稍后...第一题。1×2+2×3+3×4+...+n×(n+1）=（）第二题。1×2×3+2×3×4+3×4×5+...+7×8×9=（） - 同桌100学习网
您好，欢迎您来到！[]或[]
在线解答时间：早上8:00-晚上22:30周六、日照常
第一题。1×2+2×3+3×4+...+n×(n+1）=（）第二题。1×2×3+2×3×4+3×4×5+...+7×8×9=（）
谢谢，最好说出想的过程。
提问者：sunshuxing
上传:[注意：图片必须为JPG,GIF格式，大小不得超过100KB]
您好，欢迎来到同桌100！您想继续回答问题？您是新用户？
首先把n(n+1)拆成n^2+n，然后每一项都以此类推，左边变成(1^2+1)+(2^2+2)+(3^2+3)……（n^2+n）
然后把平方项放在一起相加，普通数字放在一起相加，得到：
（1^2 + 2^2 + 3^2 + 4^2 + …… + n^2）+(1+2+3+4+……+n)
左边的括号内是一个特例求和公式，等于n(n+1)(2n+1)/6，可用数学归纳法证明，也可用立方和公式推导，右边括号内是等差数列，不用说了吧，
你不是要乘以3吗，就在每个括号前乘以3好了，然后分别计算，再分别乘以3，最后相加得
n(n+1)(n+2)，原式即可证明
另外你可以用数学归纳法证明
复制的资料：2?=(1+1)?=1+3+3+1
3?=(1+2)?=1+3×2?+3×2+2?
(1+n)?=1+3×n?+3×n+n?
2?+3?+...+n?+(1+n)?=n+3(1+2?+...+n?)+3(1+2+...+n)+1+2?+3?+...+n?
S=n(n+1)*(2n+1)/6
回答者：teacher012
1*2*3+2*3*4+3*4*5+...+7*8*9
=1/4*1*2*3*4+1/4*[2*3*4*5-1*2*3*4]+...+1/4*[7*8*9*10-6*7*8*9]
=1/4[1*2*3*4+2*3*4*5-1*2*3*4+...+7*8*9*10-6*7*8*9]
=1/4*7*8*9*10
回答者：teacher012答案：BCABC;ACBBC;ACACA;CABCA
请选择年级高一高二高三请输入相应的习题集名称(选填)：
科目：高中英语
来源：江苏省厉庄高级中学2007届高三年级第一学期第二阶段测试　英语试题
第一部分听力
第一节(共5小题：每小题1.5分，共7.5分)
听下面5段对话。每段对话后有一道小题，从每题所给的A、B、C三个选项中选出最佳选项。听完每段对话后，你将有10秒钟的时间来回答有关小题和阅读下一小题。每段对话你将听一遍。
1．Which model did the man order most?
A．Nokia 8210．
B．Motorola C266．
C．Sony-Ericsson T628．
2．What can you infer from the dialogue?
A．The bus drivers seldom go on strike in England．
B．The bus drivers this time ask for different things．
C．The bus drivers this time again ask for less work and more pay．
3．What does the woman want to become?
A．A teacher．
B．A translator．
C．An actress．
4．What is the woman likely to do during the festival?
A．She may do anything that she will meet．
B．She will help her mother do some shopping．
C．She will help her mother do some cooking．
5．What can you learn from Jim’s reply?
A．He goes to most types of games．
B．Basketball is his only sport．
C．He plays basketball．
第二节(共15小题：每小题1.5分，共22.5分)
听下面6段对话或独白。每段对话或独白后有几道小题，从每题所给的A、B、C三个选项中选出最佳选项。听每段对话或独白前，你将有5秒钟的时间阅读每小题。听完后，每小题将给出5秒钟的做答时间。每段对话或独白你将听两遍。
听第6段材料，回答第6至7题。
6．What is the relationship between the speakers?
A．Friends．
B．Caller and operator．
C．Secretary and boss．
7．What does the man want to do?
A．He wants to know Ms．Amanda Rhodes’s telephone number．
B．He wants to find where Ms．Amanda Rhodes lives．
C．He wants to tell the woman Ms．Amanda Rhodes’s name．
听第7段材料，回答第8至10题。
8．Where hasn’t the man been in China?
A．Beijing．
B．Suzhou．
C．Shanghai．
9．What did the man buy in Xi’an?
A．An ancient jar．
B．A wonderful knife．
C．A set of china．
10．When will the woman go to the man’s house?
A．This Saturday evening．
B．This Sunday evening．
C．Next Saturday evening．
听第8段材料，回答第11至13题。
11．Where did the man work before?
A．In the bank．
B．In the shipping department．
C．In the shopping department．
12．How did the man find the wok and the workmates now?
A．The work was tiring but the people were friendly．
B．The work was interesting but the people were impolite．
C．Neither the work nor the people were satisfying．
13．What was the woman’s wish?
A．The man’s idea would come true．
B．She would make things better for the man．
C．The man would learn how to get on well with others．
听第9段材料，回答第14至16题。
14．Why is the woman worried?
A．Because she can’t speak French well．
B．Because she doesn’t have friends in Canada．
C．Because she can’t find her way to Quebec City．
15．What do we know about Montreal?
A．It is the capital of Quebec Province．
B．It is the biggest city in Quebec Province．
C．It is far away from the St．Lawrence River．
16．What can we learn from this conversation?
A．Only French is spoken in Quebec．
B．All the buildings in Quebec City are old．
C．Most people in Montreal speak French．
听第10段材料，回答第17至20题。
17．Why is the No．16 bus of no use to the man?
A．It’s always late．
B．It’s always full．
C．It gets off after the No．49 bus．
18．How long will the speaker wait for a bus sometimes?
A．One hour．
B．Ten minutes．
C．Half an hour．
19．What is the maximum number of passengers a bus is supposed to carry?
20．At what speed did a No．49 bus drive on Saturday morning?
A．60 m．p．h．
B．80 m．p．h．
C．50 m．p．h．
科目：高中英语
来源：2007年普通高等学校招生全国统一考试、英语(四川卷)
第一部分听力
第一节(共5小题；每小题1.5分，满分7.5分)
听下面5段对话．每段对话后有一个小题，从题中所给的A、B、c三个选项中选出最佳选项．听完每段对话后，你都有10秒钟的时间来回答有关小题和阅读下一小题．每段对话仅读一遍．
例：How much is the shirt?
A．￡19．15．
B．￡9．15．
C．￡9．18．
1．Who is coming for tea?
C．Tracy．
2．What will the man do next?
A．Leave fight away．
B．Stay for dinner．
C．Catch a train．
3．What does the mall come for?
A．A lecture．
B．A meeting．
C．A party．
4．What size does the man want?
5．What are the speakers talking about?
A．Life in Southeast Asia．
B．Weather conditions．
C．A holiday tour．
第二节(共15小题；每小题1.5分，满分22.5分)
听下面5段对话或独白．每段对话或独自后有几个小题，从题中所给的A、B、C三个选项中选出最佳选项．听每段对话或独白前，你将有时间阅读各个小题，每小题5秒钟；听完后，各小题将给出5秒钟的作答时间．每段对话或独白读两遍．
听第6段材料，回答第6、7题．
6．What is the man doing?
A．Giving a speech．
B．Chairing a meeting．
C．Introducing a person．
7．Why does the woman sing so well?
A．She has a great teacher．
B．She teaches singing．
C．She is young．
听第7段材料，回答第8、9题．
8．What is the second gift for Jimmy?
A．A car．
B．A watch．
C．A computer．
9．Why does Jimmy feel happy?
A．He lives with his parents．
B．He’s got what he dreamt of．
C．He’s received lots of presents．
听第8段材料，回答第10至12题．
10．What is the relationship between the speakers?
A．They are friends．
B．They are strangers to each other．
C．They are husband and wife．
11．Why does the woman come to talk with the man?
A．To get a job．
B．To take a test．
C．To see the secretary．
12．What does the man mean by saying sorry?
A．He can’t hear the woman clearly．
B．He doesn't need a designer．
C．He can’t help the woman．
听第9段材料，回答第13至16题．
13．What do we know about the woman?
A．She lives close to the office．
B．She is new to the company．
C．She likes the big kitchen．
14．How does the man go to work?
A．On foot．
B．By bus．
C．By car．
15．Why was Susan late for work?
A．She missed the bus．
B．Her train was late．
C．Her car broke down．
16．What will the man do the next day?
A．Go to work by train．
B．Visit Lily in her flat．
C．Leave home earlier．
听第10段材料，回答第17至20题．
17．Where can you most probably hear this talk?
A．In a class of the English language．
B．In a class of the Greek language．
C．In a class of the French language．
18．How long does the class last?
A．11 weeks．
B．13 weeks．
C．15 weeks．
19．What is “the short-cut” to learning words according to the speaker?
A．Taking more courses．
B．Reading basic words aloud．
C．Learning how words are formed．
20．Why is the class popular?
A．It is not offered each term．
B．It’s taught by Professor Morris．
C．It helps to master some useful rules．
科目：高中英语
来源：2013福建高考英语试题
第一部分听力(共两节，满分30分)
1．What does the man want to do?
A．Take photos．
B．Buy a camera．
C．Help the woman．
2．What are the speakers talking about?
A．A noisy night．
B．Their life in town．
C．A place of living．
3．Where is the man now?
A．On his way．
B．In a restaurant．
C．At home．
4．What will Celia do?
A．Find a player．
B．Watch a game．
C．Play basketball．
5．What day is it when the conversation takes place?
A．Saturday．
B．Sunday．
C．Monday．
笫二节(共15小题；每小题1.5分，满分22.5分)
听第6段材料, 回答第6、7题。
6．What is Sara going to do?
A．Buy John a gift．
B．Give John a surprise．
C．Invite John to France．
7．What does the man think of Sara's plan?
A．Funny．
B．Exciting．
C．Strange．
听第7段材料，回答第8、9题。
8．Why does Diana say sorry to Peter?
A．She has to give up her travel plan．
B．She wants to visit another city．
C．She needs to put off her test．
9．What does Diana want Peter to do?
A．Help her with her study．
B．Take a book to her friend．
C．Teach a geography lesson．
听第8段材料，回答第10至12题。
10．Why does the man call the woman?
A．To tell her about her new job．
B．To ask about her job program．
C．To plan a meeting with her．
11．Who needs a new flat?
B．Andrea．
C．Miranda．
12．Where is the woman now?
A．In Baltimore．
B．In New York．
C．In Avon．
听第9段材料，回答第13至16题。
13．What does Jan consider most important when he judges a restaurant?
A．Where the restaurant is．
B．Whether the prices are low．
C．How well the food is prepared．
14．When did Jan begin to write for a magazine?
A．After he came back to Sweden．
B．Before he went to the United States．
C．As soon as he got his first job in 1982．
15．What may Jan do to find a good restaurant?
A．Talk to people in the street．
B．Speak to taxi drivers．
C．Ask hotel clerks．
16．What do we know about Jan?
A．He cooks for a restaurant．
B．He travels a lot for his work．
C．He prefers American food．
听第10段材料，回答第17至20题。
17．What do we know about the Plaza Leon?
A．It's a new building．
B．It's a small town．
C．It's a public place．
18．When do parents and children like going to the Plaza Leon?
A．Saturday nights．
B．Sunday afternoons．
C．Fridays and Saturdays．
19．Which street is known for its food shops and markets?
A．Via del Mar Street．
B．Fernando Street．
C．Hernandes Street．
20．Why does the speaker like Horatio Street best?
A．It has an old stone surface．
B．It is named after a writer．
C．It has a famous university．
科目：高中英语
来源：北京市2012届高三高考预测英语试题
第一部分：听力(共两节，满分30分)
第一节(共5小题；每小题1.5分，满分7.5分)
听下面5段对话。每段对话后有一个小题，从题中所给的A、B、C三个选项中选出最佳选项。听完每段对话后，你都有10秒钟的时间来回答有关小题和阅读下一小题。每段对话仅读一遍。
1．Where does this conversation most probably take place?
A．In the hospital．
B．At a nursery．
C．In a library．
2．When are Jenny's parents coming?
A．In April．
B．In June．
C．In July．
3．What will the woman probably do?
A．Go to visit the writer．
B．Buy the writer's new book．
C．Write a book review．
4．What does the man mean?
A．The lady's room is a long way from here．
B．She has to sign up for using the lady's room．
C．She is not able to use the lady's room right now．
5．Why won't the woman eat any more?
A．She is losing weight．
B．She isn't feeling well．
C．She has had enough．
第二节(共15小题；每题1.5分，满分22.5分)
听下面5段对话或独白。每段对话或独白后有几个小题，从题中所给的A，B，C三个选项中选出最佳选项。听每段对话或独白前，你将有时间阅读各个小题，每小题5秒钟；听完后，每小题将给出5秒钟的作答时间。每段对话或独白读两遍。
听第6段材料，回答第6至7题。
6．What do we know about Kate?
A．The doctor's advice does her no good．
B．She hasn't got well though she has seen a doctor．
C．She's too busy to see a doctor．
7．Who will go to see Kate?
A．The woman．
B．The man．
C．Both of them．
听下面一段材料，回答8至10题。
8．What does the man want?
A．Less work．
B．More fun．
C．A holiday．
9．How does the man feel?
A．Dissatisfied．
B．Excited．
C．Tired．
10．What is the man's attitude towards his older generation?
B．Dislike．
听下面一段材料，回答11至13题。
11．Why does the man hire some bikes?
A．To visit the island with his friend．
B．To go to visit the bicycle rental(出租)shop．
C．To go graveling abroad．
12．What does the woman suggest?
A．See her tomorrow．
B．Go to the beach．
C．Hire a motorbike．
13．Where is the man staying?
A．At Burt's Bicycle Rental．
B．At the Holiday Sun Hotel．
C．At No．100 Teekman Street．
听下面一段材料，回答14至16题。
14．When did Meg hand in the report?
A．On September 3rd．
B．On September 5th．
C．On September 1st
15．What is the most important to Starbucks’ success?
A．The taste of its coffee．
B．Its selections of stores and service．
C．Its management．
16．What does the professor advise Meg to do?
A．To leave out some figures．
B．To change a new topic．
C．To do more research．
听下面一段材料，回答17至20题。
17．How many American rivers are seriously polluted?
A．One-sixth of them．
B．One-third of them．
C．Half of them．
18．When did Susan start the work of cleaning the river?
A．Three years ago．
B．Last August．
C．A few weeks ago．
19．What did the students find when they came to the river this year?
A．There was no garbage left to clean up．
B．The river had become to clean that a lot of water-birds came back．
C．The river was much cleaner and they had to search for garbage．
20．What was the expected reaction of the local people into the river．
A．Most of them would keep on throwing garbage into the river．
B．They would join the students in changing the situation．
C．They would become more aware of the pollution problem．新GRE作文官方题库写作第1题ARGUMENT
GRE批改分类
大家最近批改了
Woven baskets characterized by a particular distinctive pattern have
previously been found only in the immediate vicinity of the prehistoric village
of Palea and therefore were believed to have been made only by the Palean
people. Recently, however, archaeologists discovered such a "Palean" basket in
Lithos, an ancient village across the Brim River from Palea. The Brim River is
very deep and broad, and so the ancient Paleans could have crossed it only by
boat, and no Palean boats have been found. Thus it follows that the so-called
Palean baskets were not uniquely Palean.
Write a response in which you discuss what specific evidence is needed to
evaluate the argument and explain how the evidence would weaken or strengthen
the argument.
分类:Argument
话题:动物 考古
一种具有独特花纹的编织篮子以前只在史前村庄Palea的临近地区发现过，因而被认为是Palea居民所独有的。然而最近，考古学家在一个与Palea隔着一条叫做Brim河的村庄Lithos发现了一个这样的Palea篮子。Brim河很深很宽，所以古代Palea人只能坐船穿过它，但没有证据表明Palea人拥有船只。而且能够运载大量人和货物的船只直到Palea人消失几千年后才出现。而且，Palea人应该没有必要穿过这条河流--Palea周围的林地有丰富的果实和小动物。这表明那种所谓的Palea篮子并不是那里所独有的。
这种篮子不只P有。因为与他们住的地方隔一条河的地方也被发现有这个篮子，河很深只能划船过，但又没有证据证明P有船，而且能装很多人的船是在他们消失后几千年才出现的。另外P也没有必要过河，因为他们那边的山上长满了坚果草莓。
·前提不一定成立。论者是由P没有到过这里，得出篮子不只P有。但是论者没有提供任何确切的资料证明这里没有P来过的痕变，或是P的确没有来过这里。虽然P无法过河，但论者也没有告诉我们是否只有过河，P才能到这里
·论者的论据没有说服力。论者指出河很深，而P没有船，大船的出现也在P之后。但是首先论者没有提供关于史前时代这条河的状况，有可能这条大河在史前时代并不存在，或是很浅。第二虽然没有证据表明P有船，而那个时代也没有大船，但P有可能使用一些简便的类似船的工具过河，比如木板。这些都可以使P达到这里。至于论者说P那边满是食物所以没有必要到这里就更没有说服力了，首先史前时代P那边是否也满是食物论者没有说，其次P不一定必须是为食物才到其他地方去，他可能是为玩耍或是其他什么偶然的因素。
·论者的结论很武断。论者认为P没有到过这里，所以这些篮子不是P的，篮子也就不只P有。但是就算P没有到过这里，论者也没有提供证据证明其他人不会把P的篮子带到这里来，比如说这里人，比如后人。结论：论断要加强说服力还应进一步了解史前时代P人生活的状况，并对这里的地理状况提供更详细的资料。
1. The author fails to consider the possibility that the Paleans may
arrived in Lithos through other means. (I.T) ★★★★
2. The Palean basket could arrive other place through many possible methods
such as trade, or boats possessed by other culture. (I.T) ★★★★
3. In Palean times, the Brim River may not be as deep and broad as it is
currently. (C→P) ★★★
4. The fact that there are abundant resources currently does not indicate
that those resources also existed in Palean times. (C→P) ★★★
5. Other reasons other than food shortages may well result in the migration
of a culture. (I.E) ★★★
讲解来源互联网，不代表批改网观点
新东方批改网版权所有　　我想你去很多家公司面试的时候，遇到单链表倒置的问题可能比较多，如果一定要给面试题来一个排名，估计也能上top10吧，其实这个
题目玩的是技巧和你对单链表的理解，其实我们仔细想想也不是很难，既然是倒置，那我们一定是一定要走一遍单链表的，对吧，那么走单链
表有两种形式，递归和循环两种方式，而递归正是压栈和出栈，那么我们就想起来了，这不就是顺序和逆序的关系吗？第二种就是循环，还记
得我们曾今学习单链表的时候有一种插法叫做头插法，这种插入复杂度为O(1),不好的地方就是顺序插入的数字，出来的时候却是反的，所以这
个不就是可以将原先的链表原地倒置过来吗？
　 说到递归，我们脑子里面一定要有一个V型图，还有一个就是好记性不如烂笔头，算法这东西很难用脑子想的清楚的，多画画图就见青天了，
下面我就举个简单的例子：现有链表L={8,1,6,3}，需要将L倒置，然后我就画好了V型图。
从图中可以看到，当我递归到3再出栈的时候，只需要将6赋给3.next，1赋给6.next，然后这样以此类推。。。最后结果就出来了，貌似
口头上描述起来很简单，但是在写代码的时候需要注意以下几个点，先上代码说话。
public LinkNode Reverse(LinkNode node)
if (node.next == null)
var prevNode = Reverse(node.next);
var temp = node.
temp.next =
node.next = null;
return prevN
第一点：我们在走链表的时候，可以操控的只有两个结点，node和node.next，所以递归出口的时候，一定不能使用最常见的写法。
if (node == null)
　　　 而应该像下面这么写，其实就告诉我们只需要走到6节点就行了，用6.next来判断下是不是链尾，这样做是方便我们进行node和
　　　node.next进行节点交换。
if (node.next == null)
第二点：当我们每一次出栈的时候，其实也是退到曾今压栈时的方法环境中，进行节点交换的时候，也只能在当前的方法上下文中起效，比如
& & & & & 说：出栈到1的时候，其实3和6的节点已经交换了，但是1这个方法环境不知道，它仍然指向6，但此时节点6.next再也不是3了，因为
　　　 曾今3和6进行了交换，所以这不是我们所期望的，所以在回退的时候，一定要有一个链表保存这个所有节点交换的集合，恰巧在链表中
& & & & &有一个特征就是，只要我有一个指针始终指向头结点的地址，它就相当于一个集合的功能了，因为我不管你后面节点怎么转换，我都可以
& & & & &通过head.next依次找到后面痉挛的所有结点，比如下图中在出栈的过程中，每个出栈的方法环境中都依次交换了node和node.next结
& & & & &点，而我的prevnode始终指向的是结点3，所以我通过3.next就可以找到后面所有的&变化，所以这里就是prevnode的精妙之处。
最后看一下倒置的输出结果：
二：非递归实现
　　如果你知道头插法，那么循环实现真的很简单，不像递归做法很难想到那个prevnode节点，我们知道头插法是把新节点插入到链表的头部，
而我们遍历的时候又可以控制两个节点node和node.next，所以依次采用头插法，将node.next插入到node之前，有人说，那插入到node节
点之前不就乱了吗？所以在操作之前，我可以把node.next先保存起来，比如放到申请的一个叫next的节点上，为了保存新转换的节点，我们再
申请一个prev结点来保存头插法中的新节点。
为了好理解，画图如下，其实这里要注意，结点还是那些结点，并没有删除再添加。
public LinkNode Reserve(LinkNode node)
LinkNode prev = null;
LinkNode next = null;
while (node != null)
next = node.
node.next =
其实我们发现，代码只有那么一点点，但是信息量还是蛮大的，这些东西要是用口头描述还是很累的。
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