一、选择题（每小题2分、共30分）将一个正确选项前的字母填在括号内
1．在调谐放大器的LC回路两端并上一个电阻R，可以（ C ）A．提高回路的Q值B．提高谐振频率C．加宽通频带D．减小通频带2．在自激振荡电路中，下列哪种说法是正确的（C）A．LC振荡器、RC振荡器一定产生正弦波B．石英晶体振荡器不能产生正弦波C．电感三点式振荡器产生的正弦波失真较大D．电容三点式振荡器的振荡频率做不高3．如图为某收音机的变频级，以下正确叙述是（ A ）
A．电感三点式本机振荡电路
B．双回路调谐放大器取出中频信号
C．对接收信号构成共基放大电路
D．以上说法都不对
4．试用自激振荡的相位条件判别下图能产生自激振荡的电路（D）
A B C D
5．功率放大电路根据以下哪种说法可分为甲类、甲乙类、乙类、丙类等（D ）A．电路特点B．功率放大倍数C．电流大小D．功放管静态工作点选择情况6．用万用表欧姆档测量小功率三极管的电极时，应该把欧姆档拨到（A）A．R×100或R×1k档B．R×1档C．R×10档D．R×10k档7．若载波u C(t)=U C cosωC t,调制信号uΩ(t)= UΩcosΩt，则调频波的表达式为（A ）A．u FM(t)=U C cos（ωC t＋m f sinΩt）B．u FM(t)=U C cos（ωC t＋m p cosΩt）C．u FM(t)=U C（1＋m p cosΩt）cosωC t D．u FM(t)=kUΩU C cosωC tcosΩt 8．MC1596集成模拟乘法器不可以用作（C ）A．振幅调制B．调幅波的解调C．频率调制D．混频
9．某超外差接收机的中频为465kHz，当接收931kHz的信号时，还收到1kHz的干扰信号，此干扰为（ A ）A．干扰哨声B．中频干扰
C．镜像干扰D．交调干扰
10．混频电路又称变频电路，在变频过程中以下正确叙述是（C）A．信号的频谱结构发生变化B．信号的调制类型发生变化
C．信号的载频发生变化
11．二极管峰值包络检波器，原电路正常工作。若加大调制频率Ω，会引起（A）
A．惰性失真B．底部切割失真C．惰性失真和底部切割失真12．AGC电路的作用是（C）A．维持工作频率稳定B．消除频率误差
C．使输出信号幅度保持恒定或仅在很小的范围内变化
13．同步检波器要求接收端载波与发端载波（ C ）A．频率相同、幅度相同B．相位相同、幅度相同
C．频率相同、相位相同D．频率相同、相位相同、幅度相同
14．属于频谱的线性搬移过程的有（A）A．振幅调制B．频率调制C．相位调制D．角度解调
15．双边带（DSB）信号的振幅正比于（C）A．UΩB．uΩ(t)C．|uΩ(t)|
二、填空题（每小题2分，共10分）
1．石英晶体振荡器是利用石英晶体的压电和反压电效应工作的，其频率稳定度很高，通常可分为串联型晶体振荡器和并联型晶体振荡器两种。
2．为了有效地实现基极调幅，调制器必须工作在欠压状态，为了有效地实现集电极调幅，调制器必须工作在过压状态。
3．大信号包络检波器是利用二极管的单向导电性和RC网络的充放电特性工作的。4．调频有两种方法，分别称为直接调频和间接调频。
5．谐振功率放大器通常工作在丙类，此类功率放大器的工作原理是：当输入信号为余弦波时，其集电极电流为周期性余弦脉冲波，由于集电极负载的选频作用，输出的是与输入信号频率相同的余弦波。
三、简答题（每小题5分，共10分）
1．无线电通信为什么要进行调制？常用的模拟调制方式有哪些？
答： 1）信号不调制进行发射天线太长，无法架设。
2）信号不调制进行传播会相互干扰，无法接收。
常用的模拟调制方式有调幅、调频及调相
2．锁相环路与自动频率控制电路实现稳频功能时，哪种性能优越？为什么？
答：锁相环路稳频效果优越。
这是由于一般的AFC技术存在着固有频率误差问题（因为AFC是利用误差来减小误差），往往达不到所要求的频率精度，而采用锁相技术进行稳频时，可实现零偏差跟踪。
四、如图所示调谐放大器，问：
1．LC回路应调谐在什么频率上？
2．为什么直流电源要接在电感L的中心抽
头上？
3．电容C1、C3的作用分别是什么？
4．接入电阻R4的目的是什么？
（8分）
解：1. LC回路应调谐在输入信号ui的频
率上
2．直流电源要接在电感L的中心抽头上是使本电路晶体管的输出端部分接入调谐回路，其目的是要达到预定的选择性和通频带要求
3．电容C1、C3是高频旁路电容，它们的作用是保证放大器工作在放大区 4．接入电阻R4的目的是降低Q值，加宽放大器的通频带
五、已知载波电压u C(t)=5cos2π×106t，调制信号电压uΩ(t)=2cos2π×103t，令常
数k a＝1。试：
1．写出调幅表达式；
2．求调幅系数及频带宽度；
3．画出调幅波的波形和频谱图。（12分）解：1. m a=k a UΩm/U cm=0.4
u AM(t)=U Cm（1＋m a cosΩt）cosωC t=5(1+0.4 cos2π×103t) cos2π×106t
2. m a=k a UΩm/U cm=0.4 BW=2F=2kHz
3. 图（略）
六、给定调频波的中心频率f c＝50MHz，最大频偏Δf m＝75kHz，求：
1．当调制信号频率F＝300Hz时，调频指数m f及调频波有效带宽BW
2．当调制信号频率F＝15kHz时，调频指数m f及调频波有效带宽BW （10分）解：1. 调频指数m f=Δf m/F=250rad BW=2(Δf m+F)=150.6kHz
2. 调频指数m f=Δf m/F=5rad BW=2(Δf m+F)=180kHz
七、在大信号包络检波电路中，
已知：u AM（t）=10（1+0.6cos2π×103t）cos2π×106t (v), 图中
R L=4.7kΩ,C L=0.01μF,检波效率ηd=ηa=0.85
求: 1.检波器输入电阻R i
2.检波后在负载电阻R L上得到的直流电压U D和低频电压振幅值UΩm
3.当接上低频放大器后,若R L’=4kΩ,该电路会不会产生负峰切割失真?
4.按检波二极管的方向,若要实现反向AGC控制,受控管为NPN管,则AGC
电压加到受控管的哪个电极? (20分)
解：1. R i= R L /2=2.35kΩ
2. 直流电压U D=8.5V 低频电压振
幅值 UΩm=0.85×0.6×10＝5.1V
3.会产生负峰切割失真
4.＋AGC电压加到受控管的发射极
机械设计---3 一、填空题(每空1分共24分) 1.螺纹的公称直径是指螺纹的 大 径，螺纹的升角是指螺纹 中 径处的升角。螺旋的自锁条件为 v γ?≤ 。 2、三角形螺纹的牙型角α＝ 60度 ，适用于 联接 ，而梯形螺纹的牙型角α＝30度 ，适用于传动 。 3、螺纹联接防松，按其防松原理可分为 摩擦 防松、 机械 防松和 永久 防松。 4、选择普通平键时，键的截面尺寸(b ×h)是根据 轴径d 查标准来确定的,普通平键的工作面是 侧面 。 5、带传动的传动比不宜过大，若传动比过大将使 包角变大 ，从而使带的有效拉力值减小。 6、链传动瞬时传动比是 变量 ，其平均传动比是常数 。 7、在变速齿轮传动中，若大、小齿轮材料相同，但硬度不同，则两齿轮工作中产生的齿面接触应力 相同 ，材料的许用接触应力 不同 ，工作中产生的齿根弯曲应力 不同 ，材料的许用弯曲应力 不同 。 8、直齿圆柱齿轮作接触强度计算时取 节点 处的接触应
力为计算依据，其载荷由一对轮齿承担。 9、对非液体摩擦滑动轴承，为防止轴承过度磨损，应校核p ，为防止轴承温升过高产生胶合,应校核pv 。 10、挠性联抽器按是否具行弹性元件分为无弹性元件挠性联轴器和有弹性元件挠性联轴器两大类。 二、单项选择题(每选项1分,共10分) 1.采用螺纹联接时,若被联接件之—厚度较大，且材料较软，强度较低，需要经常装拆，则一般宜采用 B 。 A螺栓联接；B双头螺柱联接；C螺钉联接。 2.螺纹副在摩擦系数一定时,螺纹的牙型角越大,则 D 。 A. 当量摩擦系数越小，自锁性能越好； B．当量摩擦系数越小，自锁性能越差； C. 当量摩擦系数越大，自锁性能越差； D.当量摩擦系数越大，自锁性能越好； 3、当键联接强度不足时可采用双键。使用两个平键时要求键 D 布置。(1分) A 在同—直线上; B相隔900 ; C．相隔1200；D 相隔1800
Book 2 习题答案(unit 1-unit 5) Unit 1. Inside view 2. They have decided on: 2, 5 and 5 5, 1, c; 2. C; 3. b; 4. A; 5.d 6. 1.Maybe I should 2. Supposing 3. everything’s organized, isn’t it 4. I’ve arranged for people to 5. I’ll count it all up 6. We’d better 7. I’ve got a suggestion 8. How about Outside view 2. The true statements are 3 and 5 3. 1, one of the best universities 2. most talented students 3. well-known around the world 4. have open doors 5. good social life 6.you want it to be 7. on another campus 8. it’s a fun place 9. go to concerts 10. during the week Listening in 8. 1. b; 2. D; 3. D; 4. B ; 5, a Unit 2 Inside view 2. Kate; Kate; Janet; Janet; Janet; Janet; Kate 3 4-1-2-7-3-5-6 6. 1. b; 2, a; 3. D; 4, d; 5. D;
开放英语2复习题答案
《开放英语二》复习题I、单选题 A. Complete each sentence below by selecting the best answer from the options given. 1. - I haven't seen Belly for 10 years. - _B_____________ ____________ A. Either have I B. Neither have I C. Haven't I D. So have I 2. - What subjects are you studying? - ____C__________ _______________ ____. A. Yes, I'm studying history B. I'm studying now C. I'm studying philosophy D. I'm doing my homework 3. - I wonder if you could help me. - ___________D___ _______________ ____. A. I could B. Yes, I do C. No, not at all D. Of course 4. - Hurry up. The lecture begins at 2:00. - ____________A__
_______________ ____. A. Don't worry. We've got 20 minutes B. Thank you. No hurry C. Never mind. You go if you like D. The lecture is useful 5. - David, you've been losing your temper over nothing lately. - ____________C__ _______________ ____. A. I haven't been getting much sleep either B. You'd better not push yourself too hard, or you'll get sick C. I'm sorry. I shouldn't have blown up like that D. You'd better do exercises regularly 6. - Excuse me, I didn't mean to bother you. - ____________C__ _______________ ____. A. There's no problem B. It's a pleasure C. That's quite all right D. I didn't realize that
第二部分词汇与结构(40分) 阅读下面的句子和对话，从A、B、C三个选项中选出一个能填入空白处的最佳选项，并在答题纸上写出所选的字母符号。(每题2分，共40分) 6. David is only accountant in my father's company. A.a B. an C. the 7. I usually get up ______ 7 o'clock in the morning. A. at B. in C. on 8. _____ name is Clair. A. She B. She's C. Her 9. There is in front of the television. A. a sofa B. sofa C. many sofas 10. I don't want milk in my coffee. A. some B. any C. many 11. I'm sorry she's not in. Would you like to a message? A. leave B. rest C. keep 12. Hurry up. We don't have ______ time. A. many B. C. too many 13. You ____ go to bed and sleep. A. need B. should C. would 14. She is making ______ a cup of coffee. A. itself B .himself C. herself 15. What ____ they do on Sundays? A. have B. do C. are 16. I'm bad at spelling, but Jane is _______ than me. A. less B. bad C. worse 17. It heavily here at this moment. A. rain B. rains C. is raining 18. _______ you like to go to the pub after work? A. Would B. Should C. Could
1．在疲劳曲线上，以循环基数N0为界分为两个区：当N≥N0时，为（无限寿命区）区；当N ＜N0时，为（有限寿命区）区。 2．刚度是指机械零件在载荷作用下抵抗（弹性变形）的能力。零件材料的弹性模量越小，其刚度就越（小）。 3．润滑油的（油）性越好，则其产生边界膜的能力就越强；（粘度）越大，则其内摩擦阻力就越大。 4．为改善润滑油在某些方面的性能，在润滑油中加入的各种具有独特性能的化学合成物即为（添加剂）。 5．正是由于（弹性滑动）现象，使带传动的传动比不准确。带传动的主要失效形式为（打滑）和（带的疲劳破坏）。 6．蜗杆传动的主要缺点是齿面间的（相对滑动速度）很大，因此导致传动的（效率）较低、温升较高。 7．链传动水平布置时，最好（紧边）边在上，（松边）在下。 8．设计中，应根据被联接轴的转速、（转矩）和（直径）选择联轴器的型号。 9．径向滑动轴承的半径间隙与轴颈半径之比称为（相对间隙）；而（偏心距）与（半径间隙）之比称为偏心率 。 10．对于普通平键，考虑到载荷分布的不均匀性，双键联接的强度按（1.5 ）个键计算。 1．当所受轴向载荷通过（螺栓组形心）时，螺栓组中各螺栓承受的（轴向工作拉力）相等。2．从结构上看，带轮由（轮毂）、轮辐和（轮缘）三部分组成。 3．在直齿圆柱齿轮传动的接触疲劳强度计算中，以（节点）为计算点，把一对轮齿的啮合简化为两个（圆柱体）相接触的模型。 4．按键齿齿廓曲线的不同，花键分为（矩形）花键和（渐开线）花键。 5．请写出两种螺纹联接中常用的防松方法：（双螺母等）和（防松垫圈等）。
6．疲劳曲线是在（应力比）一定时，表示疲劳极限 与（循环次数）之间关系的曲线。 γN 7．理论上为（点）接触或（线）接触的零件，在载荷作用下，接触处局部产生的应力称为接触应力。 8．开式齿轮传动的主要失效形式是：（齿面的磨粒磨损）和（断齿）。 9．径向滑动轴承的条件性计算主要是限制压强、（速度）和（pv值）不超过许用值。10．在类型上，万向联轴器属于（无弹性元件的挠性）联轴器，凸缘联轴器属于（刚性）联轴器。 二、选择填空（每空1分，共10分） 1．下列磨损中，不属于磨损基本类型的是（ 3 ）；只在齿轮、滚动轴承等高副零件上经常出现的是（ 2 ）。 （1）粘着磨损；（2）表面疲劳磨损； （3）磨合磨损；（4）磨粒磨损。 2．在通过轴线的截面内，（1 ）的齿廓为直边梯形；在与基圆柱相切的截面内，（3 ）的齿廓一侧为直线，另一侧为曲线。 （1）阿基米德蜗杆；（2）法向直廓蜗杆； （3）渐开线蜗杆；（4）锥蜗杆。 3、对于直齿圆柱齿轮传动，其齿根弯曲疲劳强度主要取决于（4 ）；其表面接触疲劳强度主要 取决于（ 1 ）。 （1）中心距和齿宽；（2）中心距和模数； （3）中心距和齿数；（4）模数和齿宽。 4、对于径向滑动轴承，（1 ）轴承具有结构简单，成本低廉的特点；（ 3 ）轴承必须成对使 用。 （1）整体式；（2）剖分式； （3）调心式；（4）调隙式。 5．在滚子链传动的设计中，为了减小附加动载荷，应（4 ）。 （1）增大链节距和链轮齿数；（2）增大链节距并减小链轮齿数； （3）减小链节距和链轮齿数；（4）减小链节距并增加链轮齿数。 6．对中性高且对轴的削弱又不大的键联接是（ 1 ）联接。
综合教程二unit1 课后习题答案 Active reading（1） 3）．Match the words in the box with their definitions. 1 a subject that people discuss or argue about (issue) 2 a chance to do something (opportunity) 3 the most important and powerful people in the country (establishment) 4 an area of land containing all the main buildings of a university (campus) 5 something such as a meeting or public statement by people who strongly disagree with a policy, law etc (protest) 6 to start a major activity (launch) 7 chances of success, especially in a job or a career (prospects) 8 work that you are paid regularly to do for a person or company (employment) 4）. Complete the paragraph with the correct form of the words in Activity 3. What are the most important (1) issues for students today? Is the university (2) campus really such a different place compared to what it was 40 years ago? Perhaps, as the passage suggests, there are fewer (3) protests by students against the (4) establishment than there used to be. And of course, improving your (5)prospects of being competitive in the (6) employment market is a major concern for students everywhere, since a good university degree is the means by which you can (7) launch your career. But in spite of all this, the role of the university is the same as it always has been. It is the place where you have the (8) opportunity to learn to think for yourself. 5）.Replace the underlined words with the correct form of the words and phrases in the box. You may need to make other changes. 1 There were fights between police and protestors outside the US Embassy. (clashes) 2 The two parties formed a temporary political arrangement to respond to the problem. (alliance) 3 I’ve always considered myself as someone who is tolerant of other people’s idea. (liberal) 4 The chief official of an American state has a lot of power. (governor) 5 The financial situation of Western European countries rapidly improved in the 1960s. (economy) 6 The 1960s were associated with a new type of popular music. (characterized) The 1960s were characterized by a new type of popular music. 7 Mark left college without finishing the course and joined a rock band. (dropped out) 8 For many people, listening to their music was an experience which made them feel free. (liberating) For many people, listening to their music was a liberating experience. 9 For some people, an interest in politics went hand in hand with a strong enthusiasm for music. (passion) 6) . Answer the questions about the words. 1 (b) not very clearly? 2 (a) active?
开放英语(1形成性考核册作业 1答案 选择题请在在选项上画√ 1、请自我评估一下目前的英语基础 你是否掌握了本课程作为起点要求的 600基础词汇:是否√ 2、你现有的词汇量约为 -:500词,熟练使用的词汇约为:300 3、请写出你认为自己已经掌握的内容:人称代词、冠词、一般现在时、词类、 there be的句型等的用法。 下面提供一些英语学习的方法, 供你参考。但请注意,语言的运用是一种技能,这种技能不是专靠技巧能够获得的, 必须要对学习的内容本身投入较多的时间和精力。只有通过大量而反复的练习,才能真正做到熟能生巧。 (根据实际选择行当的方法用√表示 1、把英语当成获取信息、交流的工具,让英语派上用场,也让自己从学习中找到乐趣 . 2、每周制订一份切实可行的学习计划 , 帮助自己安排学习时间 , 完成学习任务 . 3、我每天都会抽出一些时间学习英语,不间断地进行听说读写的练习。 4、记忆单词时不是孤立地死记硬背 , 而是通过例句来记住它的含义 \搭配 , 并试着用它造句来加深理解和记忆。 5、学习新单词时注意它的词性及其变化形式。例如,名词要区分是可数还是不可数, 如果是可数名词,还要了解它的复数形式;动词要分清是及物,还是不及物,以及它的各种变化形式(单数第三人称的变化形式; ing 形式等等。
6、在学习新的语法知识时注意把新知识与已经掌握的联系起来,并进行归纳总结,加深理解。 7、选择自己感兴趣的内容进行阅读,如小说、幽默故事等,以保证有足够的动力坚持下去。 8、看到好的的句子就把它摘抄下来,反复诵读。 9、先跟读音内容,尽量模仿其语音语调,然后再不跟录音自己大声朗读。将自己的朗读录下来与原录音内容进行比较,找出差距。 10选择一些难度适当的听力材料反复听然后进行听力练习,争取做到一字不漏。 11、营造听力的语言环境,如听英语广播、看英语电视节目,坚持每天都有语音输入, 锻炼自己的听力。 12、学完一篇课文后,将其译为汉语,然后不看原文再将汉语译文口译回英文,这样既作了复述练习, 又作了口语练习, 同时还发掘出一些学习课文时容易忽略的地道的英语用法。 13、经常选择身边非常熟悉的人或事物,用英语进行讲述。 14、说英语的时候不刻意追求语言形式上的完全正确, 而将注意力集中在要表达的意思上。 15、经常使用英英字典。 16、经常用英语记述一些身边发生的事情。 如果你有什么好的学习方法,可以写在这里和大家共享。 认真预习和巩固复习,加强听、说、读、写训练,经常上网学习,按时完成作业。 1、下列名词的复数形式。 Parent photo bus life half child woman tooth
《大学英语》试卷考试时间：90分钟闭卷任课老师： 班级：学号：姓名：成绩：Ⅰ.Match the words in column A with the explanations in column B. (15 points) Column A Column B 1.term a.. easy to get to 2.department b. accept sth.as true 3.overseas c. give great pleasure to 4.charge d. one of several division in a university, etc. 5.worth e. abroad 6.believe f. one of the periods into which the academic year is divided 7.somewhat g.. become less tense; rest 8.convenient h.. good of useful enough to do or have 9.relax i. responsibility, care or control 10.delight j. a little II.Multiple choice questions (15 points) There are five sentences in this section. Beneath each sentence there are four choices marked A, B, C and D. Choose one or more that you think are suitable. 11. Take your camera with you. We’d like to take some of the beautiful park. A. paintings B. pictures C. files D. films 12. The is very useful. She can helps me to find many good books. A. employer B. member C. monitor D. librarian 13. Small cars are of fuel, so they have more appeal for consumers. A. free B. short C. typical D. economical 14. Next Sunday is her birthday.I ______her a bicycle as a present. A.allow B.give C.offer D.promise 15. I was in s small countryside in China. A. brought up B. bring up C. raised up D. raise up 16. Miss Yang is likely to be for promotion. A. sent B. recommended C. advised D. reported 17. The number of people invited _________ fifty, but a number of them
华南理工大学期末考试 《机械设计》试卷B 一、选择题（共30分、每小题2分） 1、链传动作用在轴和轴承上的载荷比带传动要小，这主要是因为（ C ）。 A、链传动只用来传递较小功率 B、链速较高，在传递相同功率时圆周力小 C、链传动是啮合传动，无需大的张紧力 D、链的质量大，离心力大 2、直齿圆柱齿轮传动，当齿轮直径不变，而减小模数增加齿数时，则（ C ）。 A、提高了轮齿的弯曲强度 B、提高了齿面的接触强度 C、降低了轮齿的弯曲强度 D、降低了齿面的接触强度 3、受中等冲击载荷、支承刚度较差、速度较高的两轴之间宜选用（ A ）。 A．弹性柱销联轴器 B．凸缘联轴器 C. 十字滑块联轴器 D．万向联轴器 4、带传动工作时，设小带轮为主动轮，则带的最大应力发生在带（ C ）。 A．进入大带轮处 B．离开大带轮处 C. 进入小带轮处 D．离开小带轮处 5、有一减速器传动装置由带传动、链传动和齿轮传动组成，其安排顺序以方案 （ A ）为好。 A．带传动齿轮传动链传动 B．链传动齿轮传动带传动 C．带传动链传动齿轮传动 D．链传动带传动齿轮传动 6．螺纹联接防松的根本问题在于（ C ）。 A、增加螺纹联接的轴向力 B、增加螺纹联接的横向力 C、防止螺纹副的相对转动 D、增加螺纹联接的刚度 7．为联接承受横向工作载荷的两块薄钢板，一般采用的螺纹联接类型应是（ A ）。 A．螺栓联接 B. 双头螺柱联接 C．螺钉联接 D. 紧定螺钉联接
8．齿面硬度HB ≤350HBS 的闭式钢制齿轮传动中，主要失效形式为（ B ）。 A ．齿面磨损 B ．齿面点蚀 C ．齿面胶合 D. 轮齿折断 9.不完全液体润滑滑动轴承，验算][pv pv 是为了防止轴承（ B ）。 A. 过度磨损 B. 过热产生胶合 C. 产生塑性变形 D. 发生疲劳点蚀 10、对于温度变化不大的短轴，考虑结构简单，轴承部件的轴向固定方式宜采用（ A ）。 A ．两端固定 B ．两端游动 C ．一端固定一端游动 D ．A ，B ，C 均可以 11、在蜗杆传动设计中，除规定模数标准化外，还规定蜗杆直径d 1取标准，其目的是（ B ）。 A ．限制加工蜗杆的刀具数量 B ．限制加工蜗轮的刀具数量并便于刀具的标准化 C ．为了装配方便 D ．为了提高加工精度 12、工作时承受弯矩并传递转矩的轴称为（ B ）。 A 、转动心轴 B 、转轴 C 、传动轴 D 、固定心轴 13、普通平键的主要失效是（ A ）。 A ．工作面被压溃或键被剪断 B ．工作面产生胶合破坏 C. 工作面产生过度磨损 D ．键被弯曲折断 14、带传动产生弹性滑动的原因是由于（ D ）。 A 、带不是绝对挠性体 B 、带与带轮间的摩擦系数偏低 C 、带绕过带轮时产生离心力 D 、带的紧边与松边拉力不等 15、非液体摩擦滑动轴承正常工作时，其工作面的摩擦状态是（ C ）。 A 、完全液体摩擦状态 B 、干摩擦状态 C 、边界摩擦或混合摩擦状态 D 、不确定 1．在一般工作条件下，齿面硬度HB ≤350的闭式齿轮传动，通常的主要失效形式为 【 】
Unit 1 Outside view Activity 1 Activity 2 one of the best universities most talented students well-known around the world have open doors good social life you want it to be on another campus it's a fun place go to concerts during the week Activity 3 library system online three / 3 four / 4 Brian leisure purposes the libraries listening in
Passage 1 1.2 2. 6 3.1 4.5 5.3 6.4 to Passage 1 again and rearrange the answers in the right column to match those questions in the left column. Ceahbgdf Passage 2 OC/O/C/O/C/C/O/C/O/OC to Passage 2 again and choose the best way to complete the sentences BDDBA Test CCBBD CDBCB C Unie 2 Outside view Activity 1 the video clip and match the speakers with the statements. K/K/T/S/T/K/S/K Activity 2
大学英语试题及答案一、交际英语 Can I help you, sir - _________ , I don't need your help. . I'd like to withdraw some money. , leave me alone. 't bother me! 答案：B I wonder if I could use your computer tonight - ___________ I'm not using it right now. , here you are. don't know. doesn't matter. cares 答案：A Excuse me, how much is the jacket - It's 499 Yuan. ________ , no. That's OK! do you like it do you prefer you like to try it on 答案：D It's rather cold in here. Do you mind if I close the window - ________ , please. , please. , please. don't like it. 答案：B Do you mind my smoking here - _______
, thanks. , I do. . I'd rather not. idea. 答案：B 二、阅读理解 Peter arrived home and discovered that he had forgotten his door key. He rang the bell, but nobody came to open the door. He rang again, and waited, but still there was no answer. He walked around the house to see if he could find an open window. But they were all closed. It was beginning to rain and he did not know what to do. Dorothy, his wife, had obviously gone out, and he did not know where she had gone, or when she would return. He waited for half an hour. Still nobody came. Finally feeling wet and angry, he picked up a big stone and threw it through the kitchen window and was climbing through it. When he heard the front door open, his wife came back. could not open the door with his key one day. 答案：B was raining that day. 答案：A threw a big stone through a window to get into his house. 答案：A wife came back when he was walking around the house.
Unit 1 Outside view Activity 1 3.5 Activity 2 one of the best universities most talented students well-known around the world have open doors good social life you want it to be on another campus it's a fun place go to concerts during the week Activity 3 library system online three / 3 four / 4 Brian leisure purposes the libraries listening in Passage 1 1. 2 2. 6 3. 1 4. 5 5. 3 6. 4 2.Listen to Passage 1 again and rearrange the answers in the right column to match those questions in the left column. Ceahbgdf Passage 2 OC/O/C/O/C/C/O/C/O/OC
2.Listen to Passage 2 again and choose the best way to complete the sentences BDDBA Test CCBBD CDBCB C
Unie 2 Outside view Activity 1 1.Watch the video clip and match the speakers with the statements. K/K/T/S/T/K/S/K Activity 2 2.3.5 Activity 3 regarded along communicating But If during how as plays less LISTENING IN Passage 1 1.Listen to Passage 1 and match the colours with the characteristics
《开放英语二》复习题 I、单选题 A. Complete each sentence below by selecting the best answer from the options given. 1. - I haven't seen Belly for 10 years. - _B_________________________ A. Either have I B. Neither have I C. Haven't I D. So have I 2. - What subjects are you studying? - ____C____________________________ _. A. Yes, I'm studying history B. I'm studying now C. I'm studying philosophy D. I'm doing my homework 3. - I wonder if you could help me. - ___________D_____________________ _. A. I could B. Yes, I do C. No, not at all D. Of course 4. - Hurry up. The lecture begins at 2:00. - ____________A____________________ _. A. Don't worry. We've got 20 minutes B. Thank you. No hurry C. Never mind. You go if you like D. The lecture is useful 5. - David, you've been losing your temper over nothing lately. - ____________C____________________ _. A. I haven't been getting much sleep either B. You'd better not push yourself too hard, or you'll get sick C. I'm sorry. I shouldn't have blown up like that D. You'd better do exercises regularly 6. - Excuse me, I didn't mean to bother you. - ____________C____________________ _. A. There's no problem B. It's a pleasure C. That's quite all right D. I didn't realize that 7. - Thanks a lot. You've gone to so much trouble. - ________A________________________ _. A. It's no trouble at all B. That's all right. I like it C. I don't think it's a trouble D. That's very kind of you 8. - I've ordered pizza and salad. What else do you want? - _________________________________. A. You are Ckind to invite me B. Yes, please C. A beer is fine for me. I'm not hungry yet D. I find pizza is tasty 9. - What would you like, tea or coffee? - _______B_________________________ _. A. Yes, I would B. Coffee, please C. Yes, please D. It's very nice 10. - Hello, could I speak to Don please? - ________D_________________________? A. Who are you B. What's the problem C. Are you Jane
《大学英语》试卷 考试时间：90分钟闭卷任课老师： 班级：学号：姓名：成绩：Ⅰ.Match the words in column A with the explanations in column B. (15 points) Column A Column B 1.term a.. easy to get to 2.department b. accept sth.as true 3.overseas c. give great pleasure to 4.charge d. one of several division in a university, etc. 5.worth e. abroad 6.believe f. one of the periods into which the academic year is divided 7.somewhat g.. become less tense; rest 8.convenient h.. good of useful enough to do or have 9.relax i. responsibility, care or control 10.delight j. a little II.Multiple choice questions (15 points) There are five sentences in this section. Beneath each sentence there are four choices marked A, B, C and D. Choose one or more that you think are suitable. park. A. paintings B. pictures C. files D. films 12. The is very useful. She can helps me to find many good books. A. employer B. member C. monitor D. librarian 13. Small cars are of fuel, so they have more appeal for consumers. A. free B. short C. typical D. economical 14. Next Sunday is her birthday.I ______her a bicycle as a present. A.allow B.give C.offer D.promise 15. I was in s small countryside in China. A. brought up B. bring up C. raised up D. raise up 16. Miss Yang is likely to be for promotion. A. sent B. recommended C. advised D. reported
《机械设计》试题（一） 一、选择题：本题共10个小题，每小题2分，共20分，在每小题给出的四个选项中，只有一项是符合题目要求的。把所选项前的字母填在题后的括号内。1．一般工作条件下，齿面硬度HB≤350的闭式齿轮传动，通常的主要失效形式为【B 】A．轮齿疲劳折断 B. 齿面疲劳点蚀 C．齿面胶合 D. 齿面塑性变形 2．带传动在工作时产生弹性滑动，是由于【C 】A．包角α太小 B. 初拉力F0太小 C．紧边与松边拉力不等 D. 传动过载 3．下列四种型号的滚动轴承，只能承受径向载荷的是【B 】A．6208 B. N208 C. 3208 D. 5208 4．下列四种螺纹，自锁性能最好的是【D】A．粗牙普通螺纹 B.细牙普通螺纹 C．梯形螺纹 D.锯齿形螺纹 5．在润滑良好的条件下，为提高蜗杆传动的啮合效率，可采用的方法为【C】A．减小齿面滑动速度υs B. 减少蜗杆头数Z1 C．增加蜗杆头数Z1 D. 增大蜗杆直径系数q 6．在圆柱形螺旋拉伸（压缩）弹簧中，弹簧指数C是指【D 】A．弹簧外径与簧丝直径之比值 B．弹簧内径与簧丝直径之比值 C．弹簧自由高度与簧丝直径之比值 D．弹簧中径与簧丝直径之比值 7．普通平键接联采用两个键时，一般两键间的布置角度为【B 】A．90° B. 120° C.135° D.180° 8．V带在减速传动过程中，带的最大应力发生在【D 】A．V带离开大带轮处 B. V带绕上大带轮处 C．V带离开小带轮处 D. V带绕上小带轮处 9．对于普通螺栓联接，在拧紧螺母时，螺栓所受的载荷是【D 】A．拉力 B.扭矩 C．压力 D.拉力和扭矩 10．滚子链传动中，链节数应尽量避免采用奇数，这主要是因为采用过渡链节后【D 】A．制造困难 B.要使用较长的销轴 C．不便于装配 D.链板要产生附加的弯曲应力