练习题答案
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1 《管理经济学》练习题 与 答案一、填空题1.边际产量曲线与平均产量曲线相交于 平均产量 曲线的最高点。
2产量增加的百分比率大于生产规模扩大的百分比率称为 规模收益递增 ;产量增加的百分比率等于生产规模扩大的百分比率,称为 规模收益不变 ;产量增加的百分比率小于生产规模扩大的百分比率,称为 规模收益递减 。
3.在完全竞争市场上,企业面临的需求曲线是一条在完全竞争市场上,企业面临的需求曲线是一条水平 线;在各种不完全竞争市场上,企业面临的需求曲线是一条上,企业面临的需求曲线是一条 向右下方倾斜 线。
线。
线。
4.在图形上,供给量的变动表现为在图形上,供给量的变动表现为 同一条供给曲线上点子同一条供给曲线上点子 的移动,供给的变动表现为的移动,供给的变动表现为 整条供给曲线整条供给曲线 的移动。
的移动。
5.总产量曲线、平均产量曲线、边际产量曲线都是先上升而后再下降,这种变化特征反映了 边际产量递减 规律。
6如果把等产量曲线与等成本线合在一个图上,那么等成本线必定与许多条等产量曲线中的一条相切于一点,在这个切点上就实现了 生产要素最优组合 (生产者均衡) 。
7.边际成本曲线与平均成本曲线相交于 平均成本曲线 曲线的最低点。
8.在图形上,需求的变动表现为在图形上,需求的变动表现为 整条需求曲线整条需求曲线 的移动,需求量的变动表现为的移动,需求量的变动表现为 同一条同一条需求曲线上点子需求曲线上点子 的移动。
的移动。
的移动。
9、不同的等成本线与不同的等产量线相切,形成不同的生产要素最适(优、佳)组合点,将这些点连接在一起就可得出这些点连接在一起就可得出 生产扩展线(或生产扩张线)生产扩展线(或生产扩张线)生产扩展线(或生产扩张线) 线。
线。
10、两种互补商品之间价格与需求呈 反 方向变动,两种替代商品之间价格与需求呈 同 方向变动。
方向变动。
11、当某商品的价格上升5%,而需求量减少8%时,该商品属于需求%时,该商品属于需求 富 有 弹性。
练习四一、填空题(每空1分)1、氨在血液中的主要运输形式是(谷氨酰胺)和(丙氨酸)。
2、可以编码相同氨基酸的密码子称为(同义)密码子。
3、参与DNA切除修复的酶有(DNA聚合酶Ⅰ)、(DNA聚合酶Ⅱ)、(DNA连接酶)。
4、遗传密码的特点有连续性、(方向性)、(简并性)、(变偶性)、(通用性)以及有起始密码和终止密码。
5、酪氨酸tRNA反密码子是5'-GUA-3',它能辨认mRNA上的相应密码子是(5'-UAC -3' )。
6、假尿嘧啶核苷的糖苷键是(C-C )连接。
7、mRNA分子5'末端的帽子结构是(m7Gp5'ppN )。
8、终止密码子一共有三个,它们分别是(UAA )、(UGA )、(UAG )。
9、在尿素循环中,能穿出线粒体进入细胞质继续反应的代谢物是(瓜氨酸)。
10、肽链延伸包括进位、(转肽)、(移位)三个步骤重复进行。
11、蛋白质生物合成的新生肽链是从(N )端开始,在mRNA上阅读时,密码子是从(5' )端到(3' )端。
12、RNA聚合酶复合物中σ因子的作用是(识别启动基因)。
13、可被转录的DNA链,它的顺序同转录合成的RNA链是(反向互补的)。
14、一段线性双螺旋DNA,在经过连续五次增殖后,最初的DNA占总DNA的比例为(1/32 )。
15、E.coli中某蛋白质是由250个氨基酸残基构成的单链蛋白,该蛋白质的基因长度是(255 )nm,合成该蛋白质总共需要(1000 )分子ATP。
16、DNA聚合酶Ⅰ是多功能酶,若用蛋白酶将其有限水解得到两个片段,其中小片段具有(5'→3' 核酸外切酶)活性。
17、一种氨基酸与专一的tRNA结合是由(氨酰-tRNA合成酶)决定的。
18、以RNA 为模板合成DNA 的酶叫做(逆转录酶)。
19、嘌呤核苷酸分解代谢的最终产物是(尿酸),若生成过多则出现(痛风)症。
【导语】要想学习好,死记硬背是远远不够的,多做试题是难免的,这样才能够掌握各种试题类型的解题思路,在考试中应⽤⾃如。
为⼤家准备了《六年级上册语⽂练习题及答案3篇》,供⼤家参考阅读。
1.六年级上册语⽂练习题及答案:《跟祖⽗学诗》 ⼀、查字典 “闻”⽤⾳序查字法先查___,再查_____(声调可不标);⽤部⾸查字法先查___部,再查____画。
“闻”在字典中的解释有:A、听见;B、听见的事情,消息;C、出名,有名望;D、⽤⿐⼦嗅⽓味。
请你给下⾯的“闻”选择合适的解释。
1.你闻闻这是什么⽓味?( ) 2.奶奶家⽣出的⼩⽜居然只有三条腿,成了这⼀带的`奇闻。
( ) 3.处处闻啼鸟。
( ) ⼆、看拼⾳写词语 jǐnɡɡào yáo tái bái lù shuāi lǎo tí jiào ( )( )( )( )( ) 三、辨字组词 唬( ) 瑶( ) 沥( ) 衰( ) 琥( ) 摇( ) 厉( ) 衷( ) 四、课⽂内容我知道。
1.本课选⾃________的回忆体⼩说《呼兰河传》,作者以⼀个单纯幼稚的⼩姑娘之⼝讲述了_______________________的故事。
2.联系上下⽂,说说“房盖被你抬⾛了”是什么意思,表达了祖⽗怎样的情感? 参考答案 ⼀、W wen 门 6 1.D 2.B 3.A ⼆、警告瑶台⽩鹭衰⽼啼叫 三、吓唬瑶台淅沥衰⽼ 琥珀摇摆厉害热衷 四、1.萧红童年跟祖⽗学诗 2.“房盖被你抬⾛了”意思是说作者念诗声⾳很⼤,似乎要掀翻屋顶,是⼀种夸张的写法。
表达了祖⽗对作者的关⼼与疼爱之情。
2.六年级上册语⽂练习题及答案:《青⼭不⽼》 ⼀、在括号⾥填上合适的词语。
( )的⼤树 ( )的波光 ( )的狂风 ( )的环境 ( )的设想 ( )的波浪 ⼆、指出破折号的不同⽤法(填序号)。
A.表解释说明B.表语意转换C.表声⾳断续 1.他⽤林业收⼊资助每户买了⼀台电视机——他还有宏伟设想,还要栽树,直到⾃⼰爬不起为⽌。
练习题及参考答案一、选择题1、假设欧元利率为5%,美元利率为3%,根据利率平价理论,欧元对美元的远期汇率应A、升水B、贴水C、上浮D、下浮2、按外汇管制程度不同,可将汇率划分为A、金融汇率和贸易汇率B、官方汇率与市场汇率C、名义汇率和实际汇率D、基本汇率和套算汇率3、以两国货币的铸币平价为汇率确定基础的是A、金币本位制B、金块本位制C、金汇兑本位制D、纸币流通制4、一国货币升值对其进出口贸易的影响是A、出口增加,进口减少B、出口减少,进口增加C、出口增加,进口增加D、出口减少,进口减少5、在直接标价法下,如果需要比原来更少的本币来兑换一定数量的外国货币则表明A、本币币值上升,外币币值下降,通常称为外汇汇率上升B、本币币值下降,外币币值上升,通常称为外汇汇率上升C、本币币值上升,外币币值下降,通常称为外汇汇率下降D、本币币值下降,外币币值上升,通常称为外汇汇率下降6、国际金本位制的特点是黄金可以A、自由买卖、自由铸造、自由兑换B、自由铸造、自由兑换、自由输出入C、自由买卖、自由铸造、自由输出入D、自由流通、自由兑换、自由输出入7、为使国际收支平衡表的借方总额和贷方总额相等而人为设置的项目是A、经常项目B、资本与金融项目C、错误与遗漏D、官方储备8、国际收支平衡表中记录一国的商品出口与进口的项目是A、货物B、服务C、收益D、经常转移9、以下国际收支调节政策中,能使国际收支迅速得到改善的是A、财政政策B、准备金比率政策C、贴现政策D、直接管制10、采用间接标价法的国家或地区有A、美国和英国B、美国和香港C、英国和日本D、中国和日本11、若汇率采用的是直接标价法,即A、外币数额固定B、本币数额固定C、买入价在前,卖出价在后D、买入价在后,卖出价在前E、大多数国家采用12、理论上调节国际收支的手段主要包括A、汇率政策B、货币政策C、信贷政策D、直接管制措施E、财政政策13、根据《我国外汇管理条例》的定义,外汇包括以下内容A、外国货币B、外币支付凭证C、外币有价证券D、普通提款权E、其他外汇资产14、在间接标价下标价数字变大说明A、外国货币汇率上涨B、本国货币汇率上涨C、外国货币下跌D、本国货币下跌E、本币升值15、以下哪些因素会导致本币汇率上升A、国内通货膨胀B、贸易顺差C、资本流入增加D、提高进口关税E、本国利率上升二、计算题1、计算分析题(第四版格式)假设,某国某年发生以下对外经济交易(单位:亿美元)商品出口 101.11商品进口-99.36劳务收入 25.14劳务支出-34.53经常转移-l.10直接投资-2.66证券投资 1.75其他长期投资-5.70其他短期投资 5.84错误与遗漏 x外汇储备变化 7.13根据以上资料进行分析,并回答下列问题:(1)求贸易收支差额、经常账户收支差额、资本与金融账户差额和总差额(2)求错误与遗漏的数额。
高考英语写作技巧练习题50题(答案解析)1. 描述一个人的性格很开朗,以下哪个词最合适?A. quietB. shyC. outgoingD. serious答案解析:C。
A 选项“quiet”表示安静的;B 选项“shy”表示害羞的;C 选项“outgoing”表示外向的、开朗的;D 选项“serious”表示严肃的。
只有C 选项符合描述人的性格开朗。
2. 在写作中表达“重要的”,以下哪个词更高级?A. importantB. significantC. necessaryD. useful答案解析:B。
A 选项“important”是常见的表达重要的词;B 选项“significant”有重大的、显著的意思,比“important”更高级;C 选项“necessary”表示必要的;D 选项“useful”表示有用的。
所以答案是B。
3. 形容一个地方很美丽,以下哪个词最准确?A. niceB. goodC. beautifulD. pretty答案解析:C。
A 选项“nice”可以形容人或事物好;B 选项“good”也比较宽泛;C 选项“beautiful”专门用来形容美丽,最准确;D 选项“pretty”通常形容人漂亮或事物可爱。
答案是C。
4. 表达“有趣的”,以下哪个词更地道?A. interestingB. funnyC. amusingD. delightful答案解析:A。
B 选项“funny”更多是滑稽的意思;C 选项“amusing”和D 选项“delightful”相对不那么常用。
A 选项“interesting”最地道地表达有趣的。
答案是A。
5. 表示“困难的”,以下哪个词程度最深?A. hardB. difficultC. toughD. arduous答案解析:D。
A 选项“hard”和B 选项“difficult”比较常见,程度中等;C 选项“tough”也表示艰难,但程度不如“arduous”深;D 选项“arduous”表示艰巨的、艰难的,程度最深。
练习题+答案第二章练习题一、单项选择题1、根据借贷记账法的原理,记录在账户贷方的是()。
AA.费用的增加B.收入的增加C.负债的减少D.所有者权益的减少资产和费用的增加记借,减少记贷;收入、负债和所有者权益增加记贷,减少记借。
2、我国《企业会计准则》将会计要素分为六类,《企业会计制度》将的会计科目分为()。
BA.六类B.五类C.七类D.三类资产、负债、权益、成本、损益五大类3、借贷记帐法中资产类帐户的余额一般在()。
BA.无余额B.借方C.贷方D.借方或贷方4、资产类账户期末余额的计算公式是()。
AA.期末余额 = 期初借方余额 + 本期借方发生额–本期贷方发生额B.期末余额 = 期初贷方余额 + 本期贷方发生额–本期借方发生额C.期末余额 = 期初借方余额 + 本期借方发生额D.期末余额 = 期初贷方余额 + 本期贷方发生额5、下列错误能够通过试算平衡查找的是()。
DA.重记经济业务B.借贷方向相反C.漏记经济业务D.借贷金额不等试算平衡的具体内容就是检查会计分录的借贷金额是否平衡。
6、“待摊费用”账户本期期初余额3500元,借方本期发生额1500元,本期摊销500元,则该账户期末余额为()。
B A.借方4500元 B.贷方4500元C.借方3500元 D.贷方1000元待摊费用属于资产类,按照资产类账户计算期末余额。
7、对账户记录进行试算平衡是根据()的基本原理。
CA.账户结构B.会计要素划分的类别C.会计等式D.所发生的经济业务的内容8、复式记账法是指对每一笔业务都要以相等的金额在相互联系的()中进行登记的记账方法。
DA.一个账户B.两个账户C.三个账户D.两个或两个以上的账户9、借贷记账法的记账规则是()。
DA.同增、同减、有增、有减B.同收、同付、有收、有付C.有增必有减,增减必相等D.有借必有贷,借贷必相等 D10、会计账户的开设依据是()。
CA.会计对象 B.会计要素C.会计科目 D.会计方法11、收到某单位的预付购货款存入银行,所引起的会计要素变动是() BA一项资产增加,一项资产得减少B一项资产增加,一项负债得增加C一项资产增加,一项负债得减少D一项负债增加,一项负债得减少借:银行存款(资产)贷:预收账款(负债)12、对于每一个账户来说,期末余额()。
Be动词专项练习题及答案1. I ___ a teacher. (am / is / are) 答案:am2. He ___ tall. (am / is / are) 答案:is3. They ___ students. (am / is / are) 答案:are4. We ___ in the classroom. (am / is / are) 答案:are5. You ___ my friend. (am / is / are) 答案:are6. It ___ a dog. (am / is / are) 答案:is7. She ___ beautiful. (am / is / are) 答案:is8. This ___ a book. (am / is / are) 答案:is9. Those ___ pens. (am / is / are) 答案:are10. The cat ___ on the chair. (am / is / are) 答案:is11. My mother ___ at home. (am / is / are) 答案:is12. Your father ___ happy. (am / is / are) 答案:is13. I ___ ten years old. (am / is / are) 答案:am14. He ___ a doctor. (am / is / are) 答案:is15. They ___ playing football. (am / is / are) 答案:are16. We ___ good friends. (am / is / are) 答案:are17. You ___ clever. (am / is / are) 答案:are18. It ___ my dog. (am / is / are) 答案:is19. She ___ in the park. (am / is / are) 答案:is20. This ___ my pen. (am / is / are) 答案:is21. Those ___ flowers. (am / is / are) 答案:are22. The bird ___ in the tree. (am / is / are) 答案:is23. My sister ___ nice. (am / is / are) 答案:is24. Your brother ___ tall. (am / is / are) 答案:is25. I ___ happy today. (am / is / are) 答案:am26. He ___ at school. (am / is / are) 答案:is27. They ___ watching TV. (am / is / are) 答案:are28. We ___ in the library. (am / is / are) 答案:are29. You ___ right. (am / is / are) 答案:are30. It ___ a car. (am / is / are) 答案:is31. She ___ singing. (am / is / are) 答案:is32. This ___ my house. (am / is / are) 答案:is33. Those ___ books. (am / is / are) 答案:are34. The ball ___ under the table. (am / is / are) 答案:is35. My uncle ___ kind. (am / is / are) 答案:is36. Your aunt ___ beautiful. (am / is / are) 答案:is37. I ___ a girl. (am / is / are) 答案:am38. He ___ playing the piano. (am / is / are) 答案:is39. They ___ running. (am / is / are) 答案:are40. We ___ in the park. (am / is / are) 答案:are41. You ___ tired. (am / is / are) 答案:are42. It ___ a bird. (am / is / are) 答案:is43. She ___ dancing. (am / is / are) 答案:is44. This ___ my computer. (am / is / are) 答案:is45. Those ___ oranges. (am / is / are) 答案:are46. The dog ___ on the floor. (am / is / are) 答案:is47. My cousin ___ smart. (am / is / are) 答案:is48. Your friend ___ happy. (am / is / are) 答案:is49. I ___ at home. (am / is / are) 答案:am50. He ___ reading a book. (am / is / are) 答案:is。
1第一章1-1. 晶体与非晶体的本质区别是什么?单晶体为何有各向异性而实际金属表现为各向同性?(1)晶体中的质点在空间作有规则的排列,而非晶体内部的质点排列不规则 (2)因为不同的晶面及晶向上,原子的排列情况不同,所以晶体表现为各向异性,而实际金属是由很多方向各异的单晶体杂乱排列而成,所以整体表现为各向同性。
1-4. 铜和铁室温下的晶格常数分别为0.286n m 和0.3607n m ,求1c m 3铁和铜中的原子数。
1n m (n a n o m e t e r )=10--99m =10A (a n g s t r o n g ) 铜的晶格常数=0.286 x 10--77c m 铁的晶格常数=0.3607 x 10--77c m1c m 3铜的原子数=3)710286.0(31cm x cm - x 4 = 1.71x 10231c m 3 铁的原子数=3)7103607.0(31cm x cm -x 2 = 4.26x 102221-5. 常见的金属晶体典型结构有哪几种?α-F e , γ-F e , C u , A l , N i , P b , C r , V , M o , M g , Z n , W 各属于何种晶体结构?面心立方结构、体心立方结构、密排六方结构 γ-F e , C u , A l , N i , P b - 面心立方结构 α-F e , C r , V , M o , W - 体心立方结构 M g , Z n - 密排六方结构1 作图表示立方晶系(211)、(112)、(210)、(321)、(223)、(236)晶面与[111]、[111]、[021]、[112]、[211]、[123]晶向。
解:如图所示。
(211)、(112)、(210)、(321)、(223)、(236)晶面:(211) (112) (210)1.2★作图表示立方晶系(211)、(112)、(210)、(321)、(223)、(236)晶面与[111]、[111]、[021]、[112]、[211]、[123]晶向。
非谓语动词专项练习100题(含答案)1.The great hall was crowded with many people, __many children __on their parents’ laps.A.including; seated B.including; seating C.included; sat D.included; sitting 2.It’s said that the Olympic Games __ in Beijing in 2008 will cover more events than any other Olympics did. A.holding B.to be held C.held D.to be holding 3.____for a long time, most of the crops in this area died from lacking water. A.Being no rain B.There was no rain C.To be no rain D.There being no rain 4.A street-beggar bought a lottery ticket purposelessly,__him a millionaire overnight. A.making B.makes C.to make D.made 5.In the face of the big fire in October in California, many people in the fire-stricken areas moved out _____. A.to escape burning B.to escape being burned C.escaping burned D.escaping from burning 6.Taking this medicine, if _____, will of course do good to his health. A.continued B.to continue C.continues D.continuing 7.The little boy still needs the _____20 dollars to do with some things _____. A.remaining; remained to be settled B.remaining; remaining to be settled C.remained; remained to settle D.remained; remaining to settle 8._____ his age, the little boy read quite well. A.Considering B.Considered C.Consider D.Having considered 9.___from the appearance,it is very peaceful;but in fact,a war will break out soon. A.Judged B.Judging C.Having judged D .To judge D.To judge 10. —Tom enjoys ___ basketball on Sunday afternoons, doesn’t he?— Yes, he does. But what his sister enjoys _____. A.to play; dancing B.playing; to dance C.to play; to dance D.playing; is to dance 11.His letter, _____ to the wrong number, reached me late. A.having been addressed B.to have addressed C.to have been addressed D.being addressed 12. The Space Shuttle Columbia broke into pieces over Texas as it returned to the earth on February 1, 2003, _____ all sev astronauts aboard. A.having killed B.killing C.being killed D.killed 13. There are lots of places of interest _____ in our city. A.needs repairing B.needing repaired C.needed repairing D.needing to be repaired 14. — What caused the party to be put off? What caused the party to be put off? —— _____ the invitations. A.Tom delayed sending B.Tom’s delaying sendingC.Tom delaying to send D.Tom delayed to send 15. I was afraid _____ to my customers because I was afraid _____ them. A.of talking back; to lose B.of talking back; of losing C.to talk back; to lose D.to talk back; of losing 16.Standing on the top of the hill, I would not do anything but _____ the flowing of the smog around me. A.enjoy B.enjoying C.enjoyed D.to enjoy 17.17.—— Is Tom a good talker? — No, he never speaks to me other than _____ something? A.ask for B.to ask for C.asked for D.asking for 18.I can’t get my car __ on cold mornings, so I have to try __ the radiator with some hot water.A.run; to fill B.running; filling C.running; to fill D.ran; filling 19.The drunken husband knocked against the table and sent the bowls _____ in all directions before he was sent _____ by h wife. A. flying; to sleep B. flying; sleeping C. to fly; to sleeping D. to fly; to sleep 20. When we got back from the cinema,we found the lamp ___but the door ___. A. being on; shut A. being on; shut B. burning; shutting B. burning; shutting B. burning; shutting C. burning; shut C. burning; shut D. on; shutting 21.We found the students seated at tables and had their eyes ____on the scene of the launch of Shenzhou V spaceship. A. fixed B. fix C. fixing D. to fix 22.A doctor can expect _____ at any hour of the day or night. A. calling B. to call C. being called D. to be called 23.The boy often gives a satisfactory answer to the teacher’s question, ____ just a minute. So he’s usually the teacher’s pet. A. thought B. having thought C. and to think D. thinking 24.The policeman came up to the lonely house with the door ____, ___there for a while and then entered it. A. open; to stand B. opening; stood C. open; stood D. opened; standing 25._____ along the quiet road at forty miles an hour, and then an old man suddenly started to cross the road in front of me. A. Driving B. I was driving C. Having driven D. When I was driving 26.Mr. Smith was much surprised to find the watch he had had ___was nowhere to be seen. A. repairing B. it repaired C. repaired D. to be repaired 27.What did the librarian _____ out of the library? A. permit to take B. forbid to be taken C. allow to take D. insist being taken 28. — Mum, why do you give me so much popcorn? — _____ the boring time. A. Kill B. Killing C. To kill D. Having killed 29.What Yang wanted to do when he got out of the spaceship was __the joy with all the Chinese. A. share B. shared C. having shared D. about to share 30.When she was alone at home, Mary needed a friend _____. A.playing with B.having played with C.with whom to play with D.with whom to play 31._____ the big snake, the little girl stood under the tree _____ out of life. A.Seeing; frightened B.Seeing; frightening C.Seen; frightened D.To see; frightening D.To see; frightening 32.The competitor never dreamed of __ for him to win the first prize in the 100-meter race. A.there was a chance B.there being a chance C.it being a chance D.it was a chance 33._____ everything to go wrong in advance, and you won’t feel quite so bad when it doe s. A. Having expected B. Expect C. To expect D. Expecting 34.34.—— You _____ part in the party on time. — Sorry, I was delayed by the accident. A.are to take B.have supposed to take C.were to have taken D.supposed to take 35._____ with the size of the whole earth, the highest mountain doesn’t seem high at all.A. When compared B.To compare C. While comparing D. It compared 36._____ in her best suit, the girl tried to make herself _____ at the party. A.Dressed; noticed B.Dressing; noticing C.Dressed; noticing D .Dressing; noticed D.Dressing; noticed 37.The matter _____ your study surely requires _____ carefully. A. relating to; dealing with B. related to; dealt with C. related to; being dealt with D. relating to; having dealt with 38._____ made her parents worried a lot. A. Her not to come back B. Not her to come back C. Her not coming back D. Not her coming back 39.Everything ___into consideration, they believed themselves more and returned to their positions. A.to take B.taken C.to be taken D.taking 40.He moved away from his parents and missed them ____enjoy the exciting life in New York. A. much so as to B. very much to C. too much to D. enough to 41.41.—— What do you think of the plan? — It’s easier said than _____. than _____. A. carried out B. carrying out C. carry out D. to carry out 42.Many businessmen attended the Boao Forum because they knew what __ from the forum. A. to get B. to be got C. got D. getting 43.There was a famous person at the party whom everyone would like _____to themselves. A. to introduce B. to be introduced C. introducing D. being introduced 44.44.—— Were you at home last Sunday? — Yeah! I devoted the whole day to _____ the English grammar. A. review B. reviewing C. be reviewed D. being reviewed 45.Once _____ at the shop, you will be dismissed immediately. A. caught stealing B. caught to steal C. catching stealing D. to catch to steal 46. Prices of daily goods____through a computer can be lower than store prices. A. are bought B. bought C. been bought D. buying 47._____, John returned to school from his hometown. A. The summer vacation being over B. The summer vacation is over C. Because the summer vacation over D. After the summer vacation being over 48._____ she can’t come, who will do the work?A. Supposed B. Supposing C. Having supposed D. Being supposed 49.49.—— Is there anything you want from town? — No, thank you. But I would like to get ___. A.those letters mailed B.mailed letters B.mailed letters C.to mail those letters D.those letters mail 50.After the guests left, she spent as much time as she could _____ the rooms. A. tidy up B. to clear away C. clear away D. tidying up 51._____ it or not, his discovery has shocked everyone in scientific circles. A. Believe B. To believe C. Believing D. Believed 52.To tell you the truth, I’d rather read than watch television; the programs seem __all the time.A.to get worse B.to be getting worse C.to have got worse D.getting worse 53.After the Arab states won independence, great em phasis was laid on education, with girls as well as boys _____ to go to school. A. to be encouraged B. encouraging C. encouraged D. be encouraged 54.Everyone had an application form in his hand, but no one knew which office _____. A. to send it to B. to send it C. to be sent to D. to have it sent 55.___that it was going to snow, the climbers decided to put off their attempt on the highest mountain. A. Having told B. Having been told C. Tell D. Telling 56.As is known to us all, traveling is __, but we often feel __ when we are back from travels. A.interesting; tired B.interested; tiring C.interesting; tiring D.interested; tired 57.The foreign tourists have visited many scenic spots in Shanghai,____as interpreter. A. the guide acts B. the guide acting C. acting D. acted 58.Linda is thought to___ in Africa, but I really don’t know what country she’s working in.A. have worked B. work C. be working D. be worked 59._____ 59._____ time time time and and and labor, labor, labor, cartoonists cartoonists cartoonists generally generally generally draw draw draw the the the hands hands hands of of of their characters their characters with with only only only 3 3 3 fingers fingers fingers and and and a a a thumb. thumb. A.To save B.Saved C.Saving D.Having saved 60.I am busy ____ for the entrance examination, so I can’t help ____housework at home.A.preparing; doing B.preparing; to do C.to prepare; doing D.to prepare; to do 61.In order to protect our planet, _____. A.all kinds of pollution should be reduced B.we should reduce all kinds of pollution C.the environment should be protected first D.it’s important to protect our environment62.Hoping he would not be seen, Bob stole in, ___his schoolbag and rushed out. A. picking up B. picked up C. to pick up D. having picked up 63.____money 63.____money if if if you you you can can can and and and many many many poor poor poor children children children in in in the the the poor poor poor mountainous mountainous mountainous areas areas areas will will will be be be able able able to to to go go go back back back to to to school. school. A.Having given B.Given C.To give D.Give 64.Whatever trouble Mr. White had ___with the case, he would stick to his own opinion. A.deal B.to deal C.dealt D.dealing 65.While listening to pop music, _____. A.she felt asleep B.the light went out C.someone knocked at the door D.and she couldn’t help laughing66.___ the distance was too long and the time was short, we decided not to drive to Florida. A. Discovering B. To discover C. To have discovered D. Discovered 67._____, J.K. Rowling is considered to be the best fiction writer A.Having sold millions of copies of her books B.Because millions of copies of her books are sold C.Sold millions of copies of her books D.Selling millions of copies of her books 68.What surprised me most was that there appeared a ____ look on her face on hearing the unexpected news. A.worrying B.worried C.worry D.worries 69._____ one of the most important inventions of the time, the computer helps people living in different countries to do a lot 69._____ one of the most important inventions of the time, the computer helps people living in different countries to do a lot things. A.Knowing to be B.It was known C.Known as D.Which was known to be 70.70.—— Did you enjoy yourself last night? — It’s very nice of you. I appreciated _____ to the party.A. to be invited B.to have invited C.being invited D.having been invited 71.If you go to the West Lake in Hangzhou, you will find it more attractive than commonly__. A. supposing B. to suppose C. supposed D. being supposed 72.72.—— Haven’t you seen the sign,_____ “NO PHOTOS”? — I’m really sorry I didn’tA. reads B. to read C. read D. reading 73.73.—— Do you feel like _____ out? — No. I’d rather we _____ a taxi.A. to drive; take B. to drive; took C. driving; take D. driving; took 74.74.—— Kate shouldn’t have done that sort of thing.— Whatever she did was reasonable, ____to what you had done. Besides, it’s none of your business. Get down to _____ you work. A. comparing; doing B. comparing; do C. compared; doing D. compared; do 75._____ nice and delicious, the fried chicken was soon sold out. A. Tasted B. Being tasted C. Tasting D. To taste 76.76.—The plan is heard ____ so well that we don’t have to make any changes. —The plan is heard ____ so well that we don’t have to make any changes. — It is indeed. A. to design B. designing C. designed D. design 77.W 77.While we’re developing agriculture and industry, we must prevent the earth___.hile we’re developing agriculture and industry, we must prevent the earth___. A. from polluting B. polluted C. polluting D. being polluted 78.The woman found it no good _____ her daughter too much money. A. giving B. being given C. given D. gave 79.He felt it a great honor _____ to visit me when I was in his city. A. to have been taken B. to have taken C. having taken D. being taken 80.Will you please tell me why you had no pen _____ in class, Kate? A.to have written B.to be written with C.to have been written D.to write with 81.Her dress has become loose. She appears _____ weight. A. to lose B. being lost C. losing D. to have lost 82.The building ____ will be completed in a month. It will be our lab building. A. to paint B. being painted C. to have painted D. painting 83.I find these problems are easy _____. A.to be worked out B.to work them out C.to work out D. to be worked them out 84.84.——What do you think of last night’s lecture? — _____ speaking, I thought it was rather boring. A. Real B. General C. Fair D. Honestly 85.Nancy let me repeat her instruction _____ sure that I understood what was _____ after she was away on business. A.to make; to be done B.making; doing C.to make; to do D.making; to do 86.The purpose of new drugs used on patients is to make them less painful, __ them more terrible. A.not make B.not to make C.not making D.do not make 87.As the stone was too heavy to move, I left it _____on the ground. A. laying B. lay C. lying D. lain 88.88.—— I would like to buy an expensive camera. — Well. We have several models __. A. to choose from B. of choice C. to be chosen D. for choosing st night I saw Yang Weiwei lying in bed, _____in deep thought. A. lost B. losing C. to lose D. being lost 90.Tigers _____ meat-eating animals _____ meat. A. belonged to; fed on B. belonging to; feed on C. were belonged to; feed on D. belonging to; feeding on 91.91.—— Is it _____ the bad smell that is difficult ? — Of course. A. how getting rid of B. got rid of C. to get rid of D. being got rid of 92.92.—— Have you made up your mind _____ the chance to go to France? — No. I’m practicing _____ the French language.A.to give up; to learn B.to give up; learning C.giving up; to learn D.giving up; learning 93.Never _____ off your coat; it’s rather cold outside.A. take B. taking C. to take D. taken 94.A big factory has been set up in this area ___ such goods for people all over the country. A. to produce B. producing C. produced D. being produced 95.The _____ look in her face suggested that she _____ it before. A. surprising; wouldn’t know B. surprised; hadn’t knownC. surprising; hadn’t known D. surprised; shouldn’t know96.You have no business _____ to me the way you did yesterday. A. about talking B. talking C. talked D. on talking 97.___ what he can do. He might get a job tomorrow. He might stay out of work for weeks. A.We didn’t know B .He doesn’t knowB.He doesn’t know C.There is no knowing D.It was known that 98.John’s bad habit is _____ without thorough understandingA.read B.being read C.to be read D.reading 99.She reached the top of the hill and stopped _____on a big rock by the side of the path A.to have rested B.resting C.to rest D.rest 100.We must treasure every minute because _____ time is _____ forever. A.lost; losing B.lost; lost C.losing; losing D.losing; lost 非谓语动词专项练习答案及部分解析:非谓语动词专项练习答案及部分解析:1.A 。
《空气有质量吗》练习一、填空题1、空气很轻,但是,空气还是质量的。
(选填:有、没有)2、书包、书本、桌子、椅子、人等周围所有看得见的物质,都质量。
(选填:有、没有)3、多充气20下的皮球和多充气10下的皮球质量是,因为多充气20下,皮球里的空气就要比多充气10下皮球里的空气,因此要大一些,由此我们可以得出结论:充气越多,皮球和空气的总质量 ,说明空气是。
4、放气后的皮球,与之平衡的绿豆数目。
二、判断题1、书本有质量。
()2、空气没有质量。
( )3、和相同体积的水、石头相比,空气的质量最小。
()4、物质的质量是一成不变的。
( )5、在实验过程中,可以大声喧哗,来回跑动。
()6、在使用天平过程中,需要先检查天平是否平衡。
()三、选择题1、有一种物质,它能占据空间、能流动,没有固定的形状,易压缩,重量较轻,它会是( )A.水B.空气C.石头2、在两个同样大小的塑料袋里分别装满水和空气,称量比较准确的结果是( )。
A.装满水的塑料袋重B.装满空气的塑料袋重C.两个塑料袋-样重3、下列不能证明空气有质量的是()。
A.皮球充气前后在电子天平上的示数不一样B.在平衡尺一端挂上空气球,另一端挂上相同的充气气球,平衡尺不平衡C.将气球充满气后,放在水面上,气球能浮在水面上。
4、空气总是在( )运动的。
A.向上B.向下C.循环四、解答题1、请你结合课堂所学知识,说说哪些物质具有质量?_____________________________________________________________________ _____________________________________________________________________ 2、请你结合课堂所学知识,说说物质的质量在生活中,有哪些应用?_____________________________________________________________________ _____________________________________________________________________五、实验分析题1、设计一个探究“空气是否有质量”的实验:【1】实验名称:探究“空气是否有质量”【2】我的假设:空气_________质量。
答案:第一章:1.1 简述下列概念:数据、数据元素、数据类型、数据结构、逻辑结构、存储结构、线性结构、非线性结构。
● 数据:指能够被计算机识别、存储和加工处理的信息载体。
● 数据元素:就是数据的基本单位,在某些情况下,数据元素也称为元素、结点、顶点、记录。
数据元素有时可以由若干数据项组成。
● 数据类型:是一个值的集合以及在这些值上定义的一组操作的总称。
通常数据类型可以看作是程序设计语言中已实现的数据结构。
● 数据结构:指的是数据之间的相互关系,即数据的组织形式。
一般包括三个方面的内容:数据的逻辑结构、存储结构和数据的运算。
● 逻辑结构:指数据元素之间的逻辑关系。
● 存储结构:数据元素及其关系在计算机存储器内的表示,称为数据的存储结构.● 线性结构:数据逻辑结构中的一类。
它的特征是若结构为非空集,则该结构有且只有一个开始结点和一个终端结点,并且所有结点都有且只有一个直接前趋和一个直接后继。
线性表就是一个典型的线性结构。
栈、队列、串等都是线性结构。
● 非线性结构:数据逻辑结构中的另一大类,它的逻辑特征是一个结点可能有多个直接前趋和直接后继。
数组、广义表、树和图等数据结构都是非线性结构。
1.2 试举一个数据结构的例子、叙述其逻辑结构、存储结构、运算三个方面的内容。
答:例如有一张学生体检情况登记表,记录了一个班的学生的身高、体重等各项体检信息。
这张登记表中,每个学生的各项体检信息排在一行上。
这个表就是一个数据结构。
每个记录(有姓名,学号,身高和体重等字段)就是一个结点,对于整个表来说,只有一个开始结点(它的前面无记录)和一个终端结点(它的后面无记录),其他的结点则各有一个也只有一个直接前趋和直接后继(它的前面和后面均有且只有一个记录)。
这几个关系就确定了这个表的逻辑结构是线性结构。
这个表中的数据如何存储到计算机里,并且如何表示数据元素之间的关系呢? 即用一片连续的内存单元来存放这些记录(如用数组表示)还是随机存放各结点数据再用指针进行链接呢? 这就是存储结构的问题。
在这个表的某种存储结构基础上,可实现对这张表中的记录进行查询,修改,删除等操作。
对这个表可以进行哪些操作以及如何实现这些操作就是数据的运算问题了。
.3 常用的存储表示方法有哪几种?答:常用的存储表示方法有四种:● 顺序存储方法:它是把逻辑上相邻的结点存储在物理位置相邻的存储单元里,结点间的逻辑关系由存储单元的邻接关系来体现。
由此得到的存储表示称为顺序存储结构,通常借助程序语言的数组描述。
● 链接存储方法:它不要求逻辑上相邻的结点在物理位置上亦相邻,结点间的逻辑关系是由附加的指针字段表示。
由此得到的存储表示称为链式存储结构,通常借助于程序语言的指针类型描述。
● 索引存储方法:除建立存储结点信息外,还建立附加的索引表来标识结点的地址。
组成索引表的索引项由结点的关键字和地址组成。
若每个结点在索引表中都有一个索引项,则该索引表称之为稠密索引(Dense Index)。
若一组结点在索引表中只对应一个索引项,则该索引表称为稀疏索引。
● 散列存储方法:就是根据结点的关键字直接计算出该结点的存储地址。
1.4 设三个函数f,g,h分别为 f(n)=100n3+n2+1000 , g(n)=25n3+5000n2 , h(n)=n1.5+5000nlgn 请判断下列关系是否成立:(1) f(n)=O(g(n))(2) g(n)=O(f(n))(3) h(n)=O(n1.5)(4) h(n)=O(nlgn)数学符号"O"的严格的数学定义:若T(n)和f(n)是定义在正整数集合上的两个函数,则T(n)=O(f(n))表示存在正的常数C和n0,使得当n≥n0时都满足0≤T(n)≤C·f(n)。
通俗地说,就是当n→∞时,f(n)的函数值增长速度与T(n)的增长速度同阶。
一般,一个函数的增长速度与该函数的最高次阶同阶。
即:O(f(n))=n3O(g(n))=n3O(h(n))=n1.5所以答案为:答:●(1)成立。
●(2)成立。
●(3)成立。
●(4)不成立。
1.5 设有两个算法在同一机器上运行,其执行时间分别为100n2和2n,要使前者快于后者,n至少要多大? 分析:要使前者快于后者,即前者的时间消耗低于后者,即:100n2<2n求解上式,可得答:n=151.6 设n为正整数,利用大"O"记号,将下列程序段的执行时间表示为n的函数。
(1) i=1; k=0;while(i<n){ k=k+10*i;i++;}i=1; //1k=0; //1while(i<n) //n{ k=k+10*i; //n-1i++; //n-1}由以上列出的各语句的频度,可得该程序段的时间消耗:T(n)=1+1+n+(n-1)+(n-1)=3n可表示为T(n)=O(n)(2) i=0; k=0;do{k=k+10*i; i++;}while(i<n);分析:i=0; //1k=0; //1do{ //nk=k+10*i; //ni++; //n}while(i<n);//n由以上列出的各语句的频度,可得该程序段的时间消耗:T(n)=1+1+n+n+n+n=4n+2可表示为T(n)=O(n)(3) i=1; j=0;while(i+j<=n)if (i>j) j++;else i++;}分析:通过分析以上程序段,可将i+j看成一个控制循环次数的变量,且每执行一次循环,i+j的值加1。
该程序段的主要时间消耗是while循环,而while循环共做了n次,所以该程序段的执行时间为:T(n)=O(n)(4)x=n; // n>1while (x>=(y+1)*(y+1))y++;分析:由x=n且x的值在程序中不变,又while的循环条件(x>=(y+1)*(y+1))可知:当(y+1)*(y+1)刚超过n 的值时退出循环。
由(y+1)*(y+1)<n得:y<n^0.5-1所以,该程序段的执行时间为:向下取整(n^0.5-1)(5) x=91; y=100;while(y>0)if(x>100){x=x-10;y--;}else x++;分析:x=91; //1y=100; //1while(y>0) //1101if(x>100) //1100{ x=x-10; //100y--; //100}elsex++; //1000以上程序段右侧列出了执行次数。
该程序段的执行时间为:T(n)=O(1)1.7 算法的时间复杂度仅与问题的规模相关吗?答:算法的时间复杂度不仅与问题的规模相关,还与输入实例中的初始状态有关。
但在最坏的情况下,其时间复杂度就是只与求解问题的规模相关的。
我们在讨论时间复杂度时,一般就是以最坏情况下的时间复杂度为准的。
1.8 按增长率由小至大的顺序排列下列各函数:2100, (3/2)n,(2/3)n, n n ,n0.5 , n! ,2n,lgn ,n lgn, n(3/2)答:常见的时间复杂度按数量级递增排列,依次为:常数阶0(1)、对数阶0(log2n)、线性阶0(n)、线性对数阶0(nlog2n)、平方阶0(n2)、立方阶0(n3)、k次方阶0(n k)、指数阶0(2n)。
先将题中的函数分成如下几类:常数阶:2100对数阶:lgnK次方阶:n0.5、n(3/2)指数阶 (按指数由小到大排):n lgn、(3/2)n、2n、 n!、 n n注意:(2/3)^n由于底数小于1,所以是一个递减函数,其数量级应小于常数阶。
根据以上分析按增长率由小至大的顺序可排列如下:(2/3)n < 2100 < lgn < n0.5 < n(3/2) < n lgn < (3/2)n < 2n < n! < n n1.9 有时为了比较两个同数量级算法的优劣,须突出主项的常数因子,而将低次项用大"O"记号表示。
例如,设T1(n)=1.39nlgn+100n+256=1.39nlgn+O(n), T2(n)=2.0nlgn-2n=2.0lgn+O(n), 这两个式子表示,当n足够大时T1(n)优于T2(n),因为前者的常数因子小于后者。
请用此方法表示下列函数,并指出当n足够大时,哪一个较优,哪一个较劣?函数大"O"表示优劣(1) T1(n)=5n2-3n+60lgn 5n2+O(n) 较差(2) T2(n)=3n2+1000n+3lgn 3n2+O(n) 其次(3) T3(n)=8n2+3lgn 8n2+O(lgn) 最差(4) T4(n)=1.5n2+6000nlgn 1.5n2+O(nlgn) 最优2.1 试描述头指针、头结点、开始结点的区别、并说明头指针和头结点的作用。
答:开始结点是指链表中的第一个结点,也就是没有直接前趋的那个结点。
链表的头指针是一指向链表开始结点的指针(没有头结点时),单链表由头指针唯一确定,因此单链表可以用头指针的名字来命名。
头结点是在链表的开始结点之前附加的一个结点。
有了头结点之后,头指针指向头结点,不论链表否为空,头指针总是非空。
而且头指针的设置使得对链表的第一个位置上的操作与在表其他位置上的操作一致(都是在某一结点之后)。
2.2 何时选用顺序表、何时选用链表作为线性表的存储结构为宜?答:在实际应用中,应根据具体问题的要求和性质来选择顺序表或链表作为线性表的存储结构,通常有以下几方面的考虑:1.基于空间的考虑。
当要求存储的线性表长度变化不大,易于事先确定其大小时,为了节约存储空间,宜采用顺序表;反之,当线性表长度变化大,难以估计其存储规模时,采用动态链表作为存储结构为好。
2.基于时间的考虑。
若线性表的操作主要是进行查找,很少做插入和删除操作时,采用顺序表做存储结构为宜;反之,若需要对线性表进行频繁地插入或删除等的操作时,宜采用链表做存储结构。
并且,若链表的插入和删除主要发生在表的首尾两端,则采用尾指针表示的单循环链表为宜。
2.3 在顺序表中插入和删除一个结点需平均移动多少个结点?具体的移动次数取决于哪两个因素?答:在等概率情况下,顺序表中插入一个结点需平均移动n/2个结点。
删除一个结点需平均移动(n-1)/2个结点。
具体的移动次数取决于顺序表的长度n以及需插入或删除的位置i。
i越接近n则所需移动的结点数越少。
2.4 为什么在单循环链表中设置尾指针比设置头指针更好?答:尾指针是指向终端结点的指针,用它来表示单循环链表可以使得查找链表的开始结点和终端结点都很方便,设一带头结点的单循环链表,其尾指针为rear,则开始结点和终端结点的位置分别是rear->next->next 和 rear, 查找时间都是O(1)。