作业详细解答NO.4

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《大学物理I》作业-No.03 角动量与角动量守恒-A-参考答案

《大学物理I 》作业 No.03 角动量角动量守恒定律（A 卷）班级 ________ 学号 ________ 姓名 _________ 成绩 _______一、选择题[ ]1、一质点沿直线做匀速率运动时，(A) 其动量一定守恒，角动量一定为零。

(B) 其动量一定守恒，角动量不一定为零。

(D) 其动量不一定守恒，角动量不一定为零。

答案：B答案解析：质点作匀速直线运动，很显然运动过程中其速度不变，动量不变，即动量守恒；根据角动量的定义v m r L⨯=，质点的角动量因参考点（轴）而异。

本题中，只要参考点（轴）位于质点运动轨迹上，质点对其的角动量即为零，其余位置均不会为零。

故(B)是正确答案。

[ ]2. 两个均质圆盘A 和B 密度分别为A ρ和B ρ，若A ρ>B ρ，两圆盘质量与厚度相同，如两盘对通过盘心且垂直于盘面的轴的转动惯量各为A J 和B J ，则 (A) A J >B J(B) B J >A J(C) A J ＝B J(D) A J 、B J 哪个大，不能确定答案：B答案解析：设A 、B 联盘厚度为d ，半径分别为A R 和B R ，由题意，二者质量相等，即B B A A d R d R ρπρπ22=因为B A ρρ>，所以22B A R R <，由转动惯量221mR J =，则B A J J <。

[ ]3．对于绕定轴转动的刚体，如果它的角速度很大，则 (A) 作用在刚体上的力一定很大 (B) 作用在刚体上的外力矩一定很大(C) 作用在刚体上的力和力矩都很大 (D) 难以判断外力和力矩的大小答案：D 答案解析：由刚体质心运动定律和刚体定轴转动定律知：物体所受的合外力和合外力矩只影响物体运动的加速度和角加速度，因此无法通过刚体运动的角速度来判断外力矩的大小，正如无法通过速度来判断物体所受外力的大小一样。

作业解答第二版

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北京中医药大学远程教育《英语1》作业4答案

A型题：* 1. I like to get up early so that I can get plenty of work _____before lunch.[ 1分]A.doneB.being doneC.to doD.to be done* 2. If only I ______ the English exam without much hard work.[ 1分]A.will passB.passedC.could passD.can pass* 3. Identify the errors in the following sentence:He always acts as if he is the chairman although he is nothing at all.[ 1分]A.actsB.as ifC.isD.at all* 4. Identify the errors in the following sentence:Alice is the only one of those neighbors who are always willing to help the old.[ 1分]A.the onlyB.whoC.areD.the old* 5. The ______power of the people in this town has been decreasing because most young people have left for the big cities.[ 1分]A.shoppingB.purchasingC.enduringD.spending* 6. Identify the errors in the following sentence:"Excuse me," he said, with more dignity than I would thought of possible considering his appearance.[ 1分]A.thanB.thought ofC.consideringD.appearance* 7. Identify the errors in the following sentence:Bob has mistaken me as Joe.[ 1分]A.hasB.mistakenC.meD.as* 8. She ______ her things into luggage and was in great excitement for the holiday in the West.[ 1分]A.put inB.loadedC.burdenD.packed* 9. I've never heard ______ such a thing.[ 1分]A.fromB.ofC.outD.at* 10. Identify the errors in the following sentence:On his way to school yesterday morning Prof. Wang met an old friend and stopped talking with him for quite a while.[ 1分]A.On his wayB.metC.stopped talkingD.for quite a while* 11. Your remarks are rather ______ because every one stands by her.[ 1分]A.out of the placeB.in the placeC.out of placeD.in place of* 12. Identify the errors in the following sentence:Mary was shocked to realizing that it was time for tides to come in.[ 1分]A.was shockedB.realizingC.wasD.tides* 13. I received a ______parcel yesterday and I am still wondering who may have sent it.[ 1分]A.sincereB.dullplicatedD.mysterious* 14. The police investigation discovered that three young men were ______in the robbery.[ 1分]A.caughtB.involvedC.connectedD.tightened* 15. I don't like the way ______ you laughed at her.[ 1分]A.whyB.thatC.in thatD.at which* 16. There was a long ______ silence between them after his angry words.[ 1分]A.badB.awkwardC.quiteD.embarrass* 17. He said he really couldn't ______ to offend such people in those days.[ 1分]A.spendB.takeC.costD.afford* 18. The school bus was _____by a thick fog.[ 1分]A.held upB.broken offC.kept upD.put off* 19. Children are always longing ______ Christmas because they can be presented with a lot of gifts under the Christmas tree.[ 1分]A.ofB.intoC.forD.after* 20. The children at the kindergarten ______ from 1 to 100.[ 1分]A.counted onB.counted downC.counted outD.counted for* 21. It is the boy’s laziness that ______his failure in the exam.[ 1分]A.resulted fromB.brought inC.result inD.led to* 22. The Chairman of the Trade Union suggested ______ to look into the problem.[ 1分]A.to set up a special committeeB.setting up a special committeeC.having set up aspecial committee D.to set up a committee special* 23. I remember ______ the book to you the other day when I met you on my way to the library.[ 1分]A.returningB.to returnC.returnedD.being returned* 24. Poor old George has ______ the world since his business failed.[ 1分]e down ine down withe down toe down on* 25. I’m ______ for news about them.[ 1分]A.nervousB.anxiousC.eagerD.terrible* 26. Identify the errors in the following sentence:As soon as I showed her the trick, she bursted out laughing[ 1分]A.As soon asB.showed herC.bursted outughing* 27. Identify the errors in the following sentence:I got two vases in China. All of them are expensive.[ 1分]A.gotB.vasesC.AllD.are* 28. Vickie had most probably ______her for another sort of girl.[ 1分]A.regardedB.viewedC.mistakenD.looked* 29. I don't think ______ he believed my reason because he had turned a deaf ear to me.[ 1分]A.at every momentB.for momentC.for the momentD.for a moment* 30. Identify the errors in the following sentence:She is most eagerly to know where the treasure has been hidden.[ 1分]A.mosB.eagerlyC.the treasureD.has been hidden* 31. Identify the errors in the following sentence:When I got to the cinema, the film had already started; I ought to get there earlier.[ 1分]A.got toB.had already startedC.ought to getD.earlier* 32. Identify the errors in the following sentence:He wanted to know how the way they behaved.[ 1分]A.to knowB.ow the wayC.theyD.behaved* 33. ______ at the meeting that everyone present was convinced.[ 1分]A.So forcefully he spokeB.So forcefully did he speakC.So forcefully was hespoken D.So forcefully has he spoken* 34. Identify the errors in the following sentence:Not until my mother told me the sad news last night did I knew that our neighbor Dr. Li was killed in a car accident the week before.[ 1分]A.Not untilB.the sad newsC.did I knewD.was killed* 35. In order to ______ his face, he concealed his real name from us and pretended to be a noble man.[ 1分]A.bring backB.rescueC.handleD.save* 36. The space-shuttle will land on the 18th of this month, _____ the 25th.[ 1分]A.but forB.instead ofC.onD.in* 37. When he heard the news that he was selected to study abroad, he jumped _____ joy.[ 1分]A.withB.ofC.intoD.because of* 38. Identify the errors in the following sentence:Since the beginning of this century, more and more scientists have become interested in the way how the human brain works.[ 1分]A.Since the beginningB.have becomeC.inD.the way how* 39. Identify the errors in the following sentence:After criticizing our proposal in every detail, the director went on telling us that there was nothing personal in his comments.[ 1分]A.After criticizingB.in every detailC.telling usD.nothing personal* 40. The negotiation has already been broken ______.[ 1分]A.outB.awayC.offD.in* 41. He held himself ______ for fear of saying something he would regret.[ 1分]A.onB.aboutC.upD.in* 42. He felt rather______as he was the only person who wore sportswear at the dinner party.[ 1分]A.in placeB.in the wayC.by the wayD.out of the place* 43. I hired a boat ______ I could go fishing.[ 1分]A.andB.toC.so thatD.in order* 44. The newly-retired old man looked ______ at the article on display before he made a decision to make a purchase.[ 1分]A.closelyB.closeC.nearlyD.near* 45. “We’ll do what we can to get the goods ____on time,” said the manger of the company.[ 1分]A.reached fromB.deliveredC.returnede* 46. Identify the errors in the following sentence:No matter whatever he wanted, she would give it to him.[ 1分]A.No matterB.whateverC.wantedD.would* 47. We must begin testing this instrument, ______ difficult it is.[ 1分]A.no matter whatB.no matter howC.no matter soD.no matter however* 48. Only guests of the hotel enjoy the ______of using the private beach.[ 1分]A.privilegeB.possibilityC.favorD.advantage* 49. How we______ a chance to visit your great country![ 1分]A.looked forB.longed forC.waited forD.went for* 50. What the ______ is that thing on your head?[ 1分]A.hellB.homeC.earthD.hall* 51. Identify the errors in the following sentence:That is troubling me is that I don’t have much experience in international commerce.[ 1分]A.ThatB.isC.much experienceD.in international commerce* 52. He mistook me ______ my sister from my receding figure in darkness.[ 1分]A.forB.ofC.byD.into* 53. Jim ______ to act on his own judgment, but he didn't because as a soldier he had to obey the order.[ 1分]A.would preferB.would have preferredC.preferredD.might prefer* 54. The boy leaning against the wall ______ and ______ but______ nothing and finally burst into crying.[ 1分]A.heard ... hear, listened toB.listened ... listened, heardC.heard ... from,listened D.heard ... heard of, listened* 55. His mother helped him select the pop music ______ his taste as his birthday gift.[ 1分]A.up toB.inC.toD.off* 56. Identify the errors in the following sentence:If one does not work hard, you cannot expect to succeed.[ 1分]A.IfB.oneC.youD.to succeed* 57. Identify the errors in the following sentence:After making observations for a week, Sam found why Mr. Hob bs’s short factory was so inefficient.[ 1分]A.making observationsB.for a weekC.foundD.so* 58. Identify the errors in the following sentence:There are many faults in his homework.[ 1分]A.There areB.manyC.faultsD.homework* 59. Identify the errors in the following sentence:Jonnie was not barely able to walk without help because of the bad injury in his leg.[ 1分]A.was notB.without helpC.because ofD.bad* 60. The general designer was talking to the builders of the Grand Hotel while pointing ______ the map.[ 1分]A.forB.outC.dowuD.at。

“三违”详细清单

“三违”详细清单“三违”是指“违章指挥、违规作业和违反劳动纪律”的简称。

违章指挥：主要是指生产经营单位的生产经营管理人员违反安全生产方针、政策、法律、条例、规程、制度和有关规定指挥生产的行为。

违章指挥具体包括：生产经营管理人员不遵守安全生产规程、制度和安全技术措施或擅自变更安全工艺和操作程序，指挥者使用未经安全培训的劳动者或无专门资质认证的人员；生产经营管理人员指挥工人在安全防护设施或设备有缺陷、隐患未解决的条件下冒险作业;生产经营管理人员发现违章不制止等。

违章作业：主要是指工人违反劳动生产岗位的安全规章和制度(如安全生产责任制、安全操作规程、工作交接制度等)的作业行为。

违章作业具体包括：不正确使用个人劳动保护用品、不遵守工作场所的安全操作规程和不执行安全生产指令。

违反劳动纪律：主要是指工人违反生产经营单位的劳动纪律的行为。

违反劳动纪律具体包括：不履行劳动合同及违约承担的责任，不遵守考勤与休假纪律、生产与工作纪律、奖惩制度及其他纪律等。

“三违”行为具体分类如下：NO.1 作业性违章1、上岗未出示安全作业证、未佩戴工作证。

未经三级安全教育上岗作业。

2、厂区内吸烟。

3、酒后上岗。

4、非特种作业人员从事特种作业。

4.1、未取得特种作业证的员工从事压力容器、起重、液氯充装、气割、电焊等特种作业。

4.2司机无特种车辆作业证开叉车、铲车。

5、检修设备时安全措施不落实，开始检修。

5.1、清洗置换不合格进行检修作业5.2、与系统未断开进行检修作业5.3、在未泄压的情况下进行拆卸法兰、阀门。

5.4、设备管线未置换、置换、吹扫。

6、停机检修后的设备，未经彻底检查启用。

7、进行检维修作业时，未关闭设备电源、水源及其它能源供应，释放残余能量，监护措施未落实及未设置警戒区域或未挂警示牌。

7.1、人员随意穿越警戒区域或警戒线。

8、发现隐患，未排除、报告，冒险作业。

9、工作前未检查设备(施)或设备(施)带故障、安全装置不齐全便进行操作。

九上化学4习题答案

九上化学4习题答案九上化学4习题答案在学习化学的过程中，习题是巩固知识和检验理解的重要工具。

本文将为大家提供九上化学第四章的习题答案，帮助大家更好地掌握相关知识。

第一题：下面是几种常见的化学物质，请根据其化学式写出它们的名称。

1. H2O：水2. CO2：二氧化碳3. NaCl：氯化钠4. CH4：甲烷5. C6H12O6：葡萄糖第二题：下面是几个物质的化学式，请根据其名称写出化学式。

1. 水：H2O2. 二氧化碳：CO23. 氯化钠：NaCl4. 甲烷：CH45. 葡萄糖：C6H12O6第三题：下面是几个物质的化学式，请判断它们是离子化合物还是分子化合物。

1. H2O：分子化合物2. CO2：分子化合物3. NaCl：离子化合物4. CH4：分子化合物5. C6H12O6：分子化合物第四题：下面是几个物质的化学式，请根据它们的化学式判断它们是酸、碱还是盐。

1. H2SO4：酸2. NaOH：碱3. NaCl：盐4. HCl：酸5. KOH：碱第五题：下面是几个物质的化学式，请根据它们的化学式判断它们是有机物还是无机物。

1. CO2：无机物2. CH4：有机物3. H2O：无机物4. C6H12O6：有机物5. NaCl：无机物第六题：下面是几个物质的化学式，请根据它们的化学式判断它们是单质还是化合物。

1. O2：单质2. CO2：化合物3. H2O：化合物4. N2：单质5. HCl：化合物第七题：下面是几个物质的化学式，请根据它们的化学式判断它们是金属还是非金属。

1. Na：金属2. H2O：非金属3. Fe：金属4. CO2：非金属5. Ca：金属第八题：下面是几个物质的化学式，请根据它们的化学式判断它们是酸性物质、碱性物质还是中性物质。

1. H2SO4：酸性物质2. NaOH：碱性物质3. HCl：酸性物质4. KOH：碱性物质5. H2O：中性物质通过以上习题的练习，相信大家对九上化学第四章的知识有了更深入的理解。

《大学物理AII》作业 No.04 光的偏振(参考答案)

பைடு நூலகம்
放置。
I I 0 cos 2 cos 2 (90 ) I 0 cos 2 sin 2
0 当 45 时，出射光强最大， I max
1 I 0 sin 2 (2 ) 4
1 I0 4
*3、在夏天，炽热的阳光照射柏油马路发出刺眼的反光，汽车司机需要戴上一副墨镜来遮挡。是否可用偏振片做眼镜？这比墨镜有什么优点？答：一般来讲，从路面上发出的直接射入人眼的反射光要比来自其他目标的漫射光强烈得多。通常把这种刺眼的强光叫眩光。眩光对司机的安全行车有严重的影响。戴上墨镜，可以减弱射入眼睛的光强，但并不能限制眩光。如果用偏振片做眼镜，情况就大不相同了。因为阳光（自然光）经路面反射后是部分偏振光，在入射角接近布儒斯特角时偏振度很高，近似为线偏振光。对于水平的路面来说，反射部分偏振光的强度极大的分量总是在水平方向。因此，只要使眼镜上的偏振片的偏振化方向为竖直方向，就可以强烈地吸收刺目的眩光，而对来自其他目标的漫射光的吸收则要相对小得多。这种有选择地吸收眩光的优点是墨镜所没有的。此外，墨镜对光的吸收往往对波长有选择作用，会改变观察目标的色调。而偏振片对光的吸收只对偏振态有选择作用，对波长并无选择吸收，不会改变目标
n2 ）时，反射光 n1
将为线偏振光，并且反射光与折射光的夹角为（）。（用 n1 和 n2 表示两种介 2
质的折射率） 6、单轴晶体内有一确定的方向，光沿该方向入射时折射光在晶体内只有一束，该方向称为（光轴）；除了这个方向外，一般情况下入射光在晶体内都将分为两束，一束称为（寻常光）或者 O 光，一束称为（非常光）或者 e 光。在晶体内， O 光沿各个方向传播速度（相同），，因而 O 光的子波面为球面；e 光沿各个方向传播速度（不同），因而 e 光的子波面为旋转椭球面。对于正晶体而言 O 光速度（>）e 光速度，O 光折射率（<）e 光折射率（填>或<）；对于负晶体而言，以上情况正好相反。 7、发生双折射的晶体内，O 光和 e 光都为（线偏振光）；O 光的振动方向（垂直）于其主平面，e 光的振动方向（平行）于其主平面。当入射光在晶体主截面内时， O 光和 e 光的主平面与主截面重合，此时 O 光与 e 光振动方向相互（垂直）。 8、尼科耳棱镜是利用（双折射现象）定理和（全反射）原理做成的起偏器，同时尼科耳棱镜也可做为检偏器使用。一束入射光通过旋转的检偏器，如果光强（周期性变化，并且每旋转一周出现两次最大，两次消光）则可判断入射光是线偏振光；如果光强周期性变化，但没有消光现象则可判断入射光是（部分偏振光）或者（椭圆偏振光）；如果光强没有变化，则入射光是（自然光）或者（圆偏振光）。 9、一束自然光和线偏振光的混合光，让它垂直通过一偏振片。若以此入射光束为轴旋转偏振片，测得透射光强度最大值是最小值的 5 倍，那么入射光束中自然光与线偏振光的光强比值为（1:2）。解：设入射自然光光强为 I1，线偏振光光强为 I2，混合光通过偏振片后光强为：

大学英语1在线作业4满分答案及考点分析---精品模板

1. A：Must we finish the work right now？B: No，you ________. You can do it tomorrow。

A needn’tB shouldn’tC mustn'tD can’t词汇与结构2013答案A考点：考查情态动词2。

This is George，______ class you will be taking。

A whoseB whomC whoD his词汇与结构2013答案A3. What is the train ___________ to Birmingham？A feeB tripC fareD cost词汇与结构2013答案C4。

The reporters had to fight each other for a chance to ______ the famous singer。

A instructB questionC interviewD invest答案C5.Selecting a mobile phone for personal use is no easy task because technolgy ___so rapidly.A is changingB has been changedC will have changedD will change词汇与结构2013答案A6。

For a ______ of reasons，our team will not be participating in the upcoming match.A differenceB varietyC communityD branch词汇与结构2013答案B7。

A woman came in, ______ by her daughter。

A followedB followingC followD being followed词汇与结构2013答案A8。

pep人教版六年级英语下册unit4《Then and now》单元作业练习题附答案 - 副本

Unit 4 Then and nowPart A 第一课时一、读一读，翻译下列单词。

1. easy （）2. before （）3. look up （）4. Internet （）5. ago （）6. change （）7. took （）8. at all （）9. star （） 10. time （）二、读一读，选择正确的选项。

( ) 1. — Tell me about your new school, please.— ________________.A.The teachers’ office is on the second floor.B.There was no gym in my time.C.There is a new library in it.( ) 2. — Could you see stars at night?— ________________.A.Yes, I can.B.Yes, I could saw them on the hill.C.No, I could. I liked stars.三、阅读短文，判断正(T) 误(F)。

This was my school five years ago. There was no library or gym in my old school. There were no computers either. I was in Grade 1 and we had to have PE class in the classroom because there was no playground outside. Now our school has changed a lot. I love the new school.( ) 1. My school has changed a little.( ) 2. There were some computers in my school five years ago.( ) 3. I’m now in Grade Six.( ) 4. There was one small playground in my old school.Part A 第二课时一、补充单词。

22春“英语”专业《汉语写作》离线作业-满分答案4

22春“英语”专业《汉语写作》离线作业-满分答案1. 第三人称代表着有别于作者和读者的小说世界，第一人称代表作者，第二人称代表读者。

( )A.正确B.错误参考答案：A2. By the end of the year all but two people (leave) ______.By the end of the year all but two people (leave) ______.will have left由by引导的许多时间状语往往要求谓语部分为完成时态。

如：by then，by now，by the end of，by the time that等，另外，由于句中时间状语by the end of the year意为“到今年年底时”，因此谓语部分只能用将来完成时。

句意：到今年年底，将仅剩下两个人。

3. 属于艺术分析内容的是( )A.艺术构思B.人物介绍C.直接叙述D.景物和环境的描写参考答案：AD4. The core lexicon of basic English is ( ).A. made up of French wordsB. from Latin and GrThe core lexicon of basic English is ( ).A. made up of French wordsB. from Latin and GreekC. derived from CelticD. of Germanic origin参考答案：D5. 豪放的风格充满阳刚之气，而婉约的语言风格则漫溢着阴柔。

( )A.错误B.正确参考答案：B6. 在电视广告文案中，广告文案的( )常常省略。

A.标题B.广告须由作者负责调节D.随文参考答案：A7. 与请示互相呼应、密切相关的一种公文形式是( )。

A.批复B.写作的实质就是客观事物通过作者的主观意识在恰当的文字形式中的正确反映C.命令D.决定参考答案：A8. We are ______ your letter 26 June and have acted on your instruction. A．in receipt of/duly B．We are ______ your letter 26 June and have acted on your instruction.A．in receipt of/duly B．acknowledgement of/immediatelyC．in priority of/quickly D．in arrangement of/considerablyA9. 黑色幽默的风格特征为冷峻、嘲弄、挖苦、反讽的态度与语调，甚至冷静到了麻木绝望、近乎残酷可怕的地步。

数据库原理课后题答案作业(解答)

第1章引言1．1说明物理数据独立性与逻辑数据独立性的区别。

答：在某个层次上修改数据库的模式定义而不影响位于其上层模式的能力叫做数据独立性。

有两个层次的数据独立性：物理数据独立性与逻辑数据独立性物理数据独立性：是指修改数据库的物理模式而不必重写应用程序的能力；逻辑数据独立性：是指修改数据库的逻辑模式而不必重写应用程序的能力；区别：由定义可知：他们位于数据库系统的不同的层次。

物理数据独立性：为了提高性能，偶尔在物理层做一些修改，通过物理数据独立性的特性尽量不影响逻辑层，从而达到不必重写应用程序的能力。

逻辑数据独立性：只要数据库的逻辑结构发生了变化，逻辑层就必须要做一些修改，通过逻辑数据独立性，保持视图抽象层的不变，从而达到不必重写应用程序的能力。

1．2 数据库管理员的主要作用是什么？答：DBA：一个特殊的用户，负责对DBMS进行集中的管理与控制，它就是数据库管理员--DBA--Database Administrator；DBA的职责包括：决定数据库中的信息内容和结构；决定数据库的存储结构和存取策略；定义数据的安全性和完整性约束；监控数据库的使用和运行；数据库的性能改进、重组和重构，以提高系统的性能。

1．3 举例说明数据库模式和实例间的区别。

答：数据库中的数据会随时发生变化，特定时刻存储在数据库中的信息集合称作数据库的一个实例。

而数据库的总体设计，即数据库的样子，称作数据库模式，按照抽象层次的不同，可分为物理模式、逻辑模式和子模式。

例如：若要存储学生的信息，首先要对存储学生的信息即属性（如：学号、姓名、性别、年龄等）进行抽象，并对属性进行物理层和逻辑层的描述，而实例仅仅是一个具体学生的信息（例如：20050808111,张三、男，1980.10.13），其存储等各种操作按照数据库模式的描述进行。

1．4举例说明数据3层抽象间的区别。

答：数据库管理系统通过如下三个层次的抽象来向用户屏蔽复杂性，简化系统的用户界面：物理层抽象、逻辑层抽象和视图层抽象。

KYT(危险预知训练)

・搬铝板，手放板时，因手抽出时太迟手被挟在板和板之间。
・两手抱着铝板在胸前，放置时脚挂到地面上的板跌倒了
状况你是正将10块铝板（长60ｃｍ宽45ｃｍ厚さ1.5ｃｍ重量12ｋｇ）从台车上卸下、堆叠到置場。
表ＮＯ，５铝板搬运
隐藏着什么样的危险呢?
・将聚乙烯袋放入回收车中时手打到了回收车的角上。・把聚乙烯袋从桶中取出时
・用前叉叉货物搬运时因地面高低面差异叉子摇动货物倒塌砸到其他作业者。
状况你是在仓库内正用电动叉车搬运货物。
表ＮＯ，１２货物运输２
隐藏着什么样的危险呢?
・货物从卡车上移到升降台上时小脚轮被卡入货台和升降面中间的缝隙中头被货物的角打中。
・货物往升降面上移动时因其他作业员按了开关货物倒塌了砸到了下面的人。
・货物移到升降面上时脚被夹在了货台和升降面中的缝隙中。
・推货物时因货台和升降机的中间有缝隙货物被挂住后从升降机上掉下砸到了下面的人。
状況你是正将卡车运来的货物（文件柜）从升降器上卸到地面。
表ＮＯ，１３卸货
指差唱和的推进
眼睛手
声音
指差唱和
・如何防止人为失误「防止人为失误事故」
错觉、揣测判断、无意间疏忽人类特性=人是有耐性的生物
[0灾害！行动！]
知识回顾 Knowledge Review
放映结束感谢各位的批评指导！
谢谢！
让我们共同进步
ＫＹＴ（危险预知训练）
１．ＫＹＴ（危险予知训练）的概要 ①作业的状况用插图等描述 ②作业中潜伏的「危险要因」及引起危险隐患「現象」 ③部门成员商讨、考虑、再解决 ④危险的重点和确定行动目标、指差唱和确认 ⑤行动前先确认安全这种训练叫作危险予知训练 NhomakorabeaＫＹＴ）。

《大学物理AI》作业 No.04 机械能、机械能守恒定律(参考解答)

与地接触，再将弹簧上端缓慢地提起，直到小球刚能脱离地面为止。在此过程中外力所作的功为
m2g2
（
）。
2k
解：缓慢提起弹簧意味着弹簧保持一种准静态平衡，外力大小和弹簧的弹力大小始终相等。设小球刚
1
离开地面时伸长量为 x0
，由 kx0

mg
知 x0

mg k
在此过程中外力的功为 A
x0 0
k
xd
研究对象
质点（质量 m）
质点系
（质量 M，质心速度 vc ，各质点相对质心速度为 vi ）
定轴刚体
（转动惯量 J ）
动能表达式
（ Ek

1 2
mv 2
）
（ Ek

1 2
Mvc 2

i
1 2
mvi2
）
（
Ek

1 2
J 2
）
与动量（p）或角动量（L）的关系
（ Ek

p2 2m
）
（ Ek
4
2.如图所示，长为 l、质量为 m 的均匀细杆可绕水平光滑固定轴 O 转动，开始时
O
杆静止在竖直位置 B 处。另一质量也为 m 的小球，用长也为 l 的轻绳系于 O 轴
m
1 l
上。现将小球在竖直平面内拉到 A 处，与竖直方向的夹角为1，然后放手，小
2
m
球自由下摆与杆下端发生完全非弹性碰撞。求：（1）小球与细杆碰撞前瞬间速度的大小；
解：振动过程中弹簧与墙间存在作用力，所以动量不守恒；振动过程中，势能与动能相互转换，所以动能不守恒；振动过程中弹簧与墙间的作用力并不作功（力作用点没有位移），所以机械能守恒。如果以小车为参考系，振动过程中弹簧与墙间的作用力有位移，要做功，所以这种情况机械能不守恒。

外贸业务操作实务作业及答案

外贸业务操作实务试卷（A 卷）第1页（共14页）2008年全国外贸业务员培训认证考试外贸业务操作实务试卷一、出口报价核算与发盘操作（共15分）根据以下业务背景资料,回答相关问题。

福建新隆进出口有限公司（Fujian Xinlong I/E Co 。

, Ltd 。

）是一家流通型外贸企业。

2008年4月8日，该公司外贸业务员赵萍收到来自加拿大客户LK Footwear Inc.的电子邮件,内容如下： Dear Miss Zhao,We are interested in your Pac Boots Style No 。

NM1048, which is displayed at the last Canton Fair 。

Please quote us the price on FOB Xiamen ， CFR Vancouver, Canada seperately and payment by T/T against the fax of B/L 。

Looking forward to your early reply. Best regards ， Anne赵萍立即通知雪地靴的供应商福州红景制鞋厂报价，次日收到其报价如下:雪地靴，最低起订量1200双，RMB¥93.6元/双（含税价）,增值税税率为17%，每双装1个纸盒，每6盒装一个标准出口纸箱，纸箱尺寸为70厘米×45厘米×40厘米，每箱毛重为12千克，净重为10千克，1200双装1×20’FCL ,月生产能力为5000双，交货时全额付款，工厂交货。

1．经查询，该雪地靴的H 。

S 。

编码为6403120090,监管证件代码为B ，出口退税税率为11％；若4月9日的美元牌价按USD1=RMB¥6.988/ 7。

016计,为了防范美元贬值的汇率风险，公司规定，每1美元每月扣减6分人民币，这笔业务预期的收款时间约3个月；国内运费为RMB¥2400/20’FCL ,其他所有国内费用为采购成本的3%；厦门至温哥华的海运费为USD1560/20’FCL ；预期成本利润率为10％。

大学英语3(专升本)阶段性作业4

单选题1. — Tomorrow is my birthday.—__________ (2分)(A) Oh, I have no idea.(B) I'm glad you like it.(C) Many happy returns of the day!(D) You must be very happy.参考答案：C2. — How do you like Steven Spielberg’s movies？— ______________.(2分)(A) Oh, I love his movies.(B) Yes, I like it.(C) I’m watching one for the moment.(D) You know him?参考答案：A3. .— Why didn’t you come to my birthday party yesterday? — ______________________.(2分)(A) Well, my friend sent me a flower.(B) Fine, I never go to birthday parties.(C) Ha… ha, I don’t like birthday parties.(D) Sorry, but my wife had a car accident.参考答案：D4. — Thank you for inviting me. I had a good time.— ____________________.(2分)(A) I really had a happy time.(B) Oh, it’s too late.(C) Thank you for coming.(D) Oh, so slowly?参考答案：C5. — Paul, _________________?— Oh, that’s my father! And beside him, my mother. (2分)(A) who is the guy over there(B) who’s talking over there(C) what are they doing(D) which is that参考答案：B6. — Haven’t seen you for ages! What are you busy doing now?— _____________________. (2分)(A) I hate the weather here.(B) My hair is getting a bit longer.(C) Yeah, thanks for coming.(D) I’m working part time in a bookshop.参考答案：D7. — Hey, Tom, what’s up?— _________.(2分)(A) Oh, not much.(B) Yes, definitely!(C) What is happening in your life?(D) You are lucky.参考答案：A8. — I wish to propose a toast to our friendship.— _________________.(2分)(A) Let’s drink.(B) Bottoms up!(C) Great!(D) I also want to propose a toast.参考答案：B9. — Oh, Betty, we will be having a buffet party next Saturday, and we'd like you tojoin us.— __________, Susan. What's the occasion? What time do you want me to come?(2分)(A) I'd love to(B) No way(C) By no means(D) I'm afraid not参考答案：A10. — Are you getting a new flat this year?—__________I can't afford to pay my bills, let alone buy anew flat.(2分)(A) Without question.(B) You must be joking.(C) Good idea!(D) Are you sure?参考答案：B11. — How are you feeling?— Much better. __________(2分)(A) Thanks for coming to see me.(B) You look great.(C) You are so kind.(D) Don't mention it.参考答案：A12. — Could you be so kind as to turn down that rock n’roll? I'm preparing for tomorrow's exam.—__________ (2分)(A) It's none of your business.(B) What are you doing?(C) Sure. Sorry to disturb you.(D) No, I don't think so.参考答案：C13. — We are going to have a singing party tonight. Would you like to join us?— ___________________________.(2分)(A) I’m afraid not, because I have an important meeting.(B) Of course not. I have no idea.(C) No, I would not like it.(D) It’s all set.参考答案：A14. — What can I do for you?— _________________.(2分)(A) I want a kilo of pears.(B) You can do it in your own way.(C) Thanks(D) Excuse me. I’m busy.15. — This box is too heavy for me to carry upstairs.— _______________.(2分)(A) You may ask for help.(B) Let me give you a hand.(C) Please do me a favor.(D) I’d come to help.参考答案：B阅读理解America is growing older. Fifty years ago, only 4 out of every 100 people in the United States were 65 or older. Today, 10 out of every 100 Americans are over 65. The aging of the population will affect American society in many ways —education, medicine, and business. Quietly the graying of America. has made us a very different society — one in which people have a quite different idea of what kind of behavior is suitable at various ages.A person’s age no longer tells you anything about his/her social position, marriage or health. There’s no longer a particular year in which one goes to school or goes to work or gets married or starts a family. The social clock that kept us on time and told us when to go to school, get a job, or stop working isn’t as strong as it used to be. It doesn't surprise us to hear of a 29-year-old university president or a 35-year-old grandmother, or a 70-year-old man who has become a father for the first time. Public notions are changing.Many people say, "I am much younger than my mother — or my father — was at my age." No one says "act your age" anymore. We've stopped looking with surprise at older people who act in youthful ways.(17.5分)16). It can be learnt from the text that the aging of the population in America ____.(3.5分)(A) has made people feel younger(B) has changed people’s social position(C) has changed people’s understanding of age(D) has slowed down the country’s social development17). The underlined word “one” refers to ______.(3.5分)(A) a society(B) America(C) a place(D) population参考答案：A18). We can infer from the text that if a 25-year-old man becomes general manager of a big firm, the writer would most probably consider it _________.(3.5分)(A) normal(B) wonderful(C) unbelievable(D) unreasonable参考答案：A19). “Act your age” means people should ________.(3.5分)(A) be active when they are old(B) do the right thing at the right age(C) show respect for their parents young or old(D) take more physical exercise suitable to their age参考答案：B20). This passage is mainly about ____________________.(3.5分)(A) why American society is different(B) suitable behaviors at different age in American’s eyes(C) how older people act in youthful ways in America(D) how American people’s ideas about age have changed参考答案：DJust as the degree of individual freedom in America seems loose and therefore uncomfortable to many visitors, in many countries, people will tell you　what they think you want to hear, whether or not it is true. To them, this is the polite thing to do. To Americans it is considered confusing — even dishonest — to avoid telling the truth, even if the only purpose is to be polite. It is helpful to remember that different cultures consider some matters more important than others. For Americans, however, trust and truth are mostimportant. One of the worst things that can be said about someone in America is that “you cannot trust him.”Considering such differences in values among many cultures of the world, it is natural that misunderstandings occur. “How far is it to the next town?” an American asks a man standing by the road. In some countries , because the man realizes the traveler is tired and eager to reach the next village, he will politely say, “Just down the road”. He thinks this is more encouraging, gentler, and therefore the answer the traveler wants to hear. So the American drives alone for many more hours before he comes to the village. The traveler is angry, with a feeling of being fooled. He thinks that the man haslied to him on purpose because he must have known quite well what the distance was.If a visitor to the United States asked an American standing by the road how far the next town was, the American wouldthink it dishonest if he said it was near when he knew it was really 24 miles away. Although he, too, would be sympathetic with the tired traveler, he would say, “You have a long way to go yet; it is at least 24 miles more.” The traveler might be disappointed , but he would know what to expect, and there would be no misunderstanding.(17.5分)21). People in other cultures choose not to tell the truth to the visitors because _______________.(3.5分)(A) they try to confuse the visitors(B) they consider it comfortable(C) they try to be polite(D) they consider it helpful参考答案：C22). Americans insist on telling the truth because__________________.(3.5分)(A) they don’t mind confusing people(B) they are not considerate(C) they are not polite(D) they value trust and truth参考答案：D23). In paragraph 2, the misunderstanding occurs because____________________.(3.5分)(A) the man standing by the road doesn’t know where the American is going(B) the man standing by the road is dishonest and lied to the American(C) the man standing by the road wants to encourage the American(D) the man standing by the road knows the shortest way to the village参考答案：C24). We can infer from paragraph 3 that ____________________.(3.5分)(A) the American has no idea about how tired the traveler is(B) the American considers honesty important(C) the American wants to disappoint the traveler(D) the American knows what the traveler wants to hear参考答案：B25). What is the writer’s attitude toward the different cultures? (3.5分)(A) The writer thinks it natural for people in different cultures to misunderstand each other.(B) The writer thinks American culture better than many cultures of the world.(C) The writer thinks American culture worse than many cultures of the world.(D) The writer thinks people will always get confused with the cultural differences.参考答案：AA new study suggests that the more teenagers watch television, the more likely they are to develop depression（忧郁症）as young adults. But the extent to which TV may or may not be to blame is a question that the study leaves unanswered.The researchers used a national long-term survey of adolescent health to investigate the relationship between media use and depression. They based their findings on more than four thousand adolescents who were not depressed when the survey began in 1995.As part of the survey, the young people were asked how manyhours of television or videos they watched daily. They were also asked how often they played computer games and listened to the radio. Media use totaled an average of 5.5 hours a day. More than 2 hours of that was spent watching TV.Seven years later, in 2002, more than 7 percent of the young people had signs of depression. The average age at that time was 21. Brian Primack at the University of Pittsburgh medical school was the lead author of the new study. He says every extra hour of television meant an 8 percent increase in the chances of developing signs of depression. The researchers say they did not find any such relationship with the use of other media such as movies, video games or radio. But the study did find that young men were more likely than young women to develop depression, given the same amount of media use.Doctor Primack says the study did not explore if watching TV causes depression. But one possibility, he says, is that it may take time away from activities that could help prevent depression, like sports and socializing. It might also interfere with sleep, he says, and that could have an influence.(17.5分)26). According to the passage, the researchers have found________________________.(3.5分)(A) in what way watching TV causes depression(B) why teenagers like to watch TV(C) the relationship between depression and the use of all forms of media(D) the relationship between depression and watching TV参考答案：D27). As used in paragraph 2, the word “adolescent” means________________.(3.5分)(A) teenager(B) media use(C) young adult(D) average age参考答案：A28). About the methodology of the research, the writer has mentioned all of the following except that _______________. (3.5分)(A) the research was made nationwide(B) the research was made between 1995 and 2002(C) the adolescents in the survey were all depressed(D) the adolescents were asked how they used various types of media参考答案：C29). Which of the following is true about the findings of the research?(3.5分)(A) all the young people in the survey had signs of depression(B) watching TV longer implies higher risk of developing depression(C) not only TV, movies too, can result in depression(D) men and women had equal chances of developing depression 参考答案：B30). The tone of this passage can be described as__________________.(3.5分)(A) critical(B) argumentative(C) emotional(D) factual参考答案：DWhen having a meal, a European usually holds the knife in the right hand, and the fork in the left. He uses the knife and fork with his both hands. He keeps his knife and fork in his hands until he finishes eating.But an American, on the opposite, may use just one hand whenever possible and keep the other hand on his lap. He uses the fork in his right hand to pickup fried potatoes. When he has to cut his meat, he changes his fork to the left hand and cuts it. Then he puts down the knife and changes his fork to his right hand to pick up the sliced meat. Then, perhaps, he will suddenly think of his coffee or orange. So he has to put down his fork in order to drink his coffee or orange. Now you can see, an American is busy all the time at the dinner table. By the way, Europeans usually have their coffee after meals, but many Americans prefer to have coffee during the meal.If you are present at a formal dinner, you might be confused to find so many forks, knives and spoons put before you. You might be at a loss to know what to do with them. Don’t worry. The rule is simple. You just use them in the order in which they lie, beginning from outside towards the plate. The small fork on the outside on the left is for salad. The spoon on the outside on the right is for soup. There is another little knife, called a butter spreader, on a bread-and-butter plate on the left. As the bread is passed, each guest helps himself and puts his pieces on the small plate. Next to the soup there will probably be the blunt knife for fish, which is smaller and blunter than other knives.(17.5分)31). When do Europeans usually drink their coffee?(3.5分)(A) Before meals.(B) After meals.(C) While they are having their meals.(D) They never drink coffee when they eat.参考答案：B32). The right way to use the forks, knives and spoons is to use __________________.(3.5分)(A) whichever you like when necessary(B) them from the outside to the inside(C) them from the inside to the outside(D) them from the middle to both sides参考答案：B33). The butter spreader is ____________________. (3.5分)(A) a fork(B) a spoon(C) a knife(D) a plate参考答案：C34). The spoon on the outside on the right is for_______________.(3.5分)(A) soup(B) salad(C) butter(D) chicken参考答案：A35). The best title for this passage is ___________________.(3.5分)(A) Eating Habits in America.(B) Eating Habits in Europe(C) How to Use Forks, Knives and Spoons(D) Dinning Customs of the West参考答案：D。

北语-18秋《英汉汉英翻译》作业1234

18秋《英汉／汉英翻译》作业_1一、单选题( 每题4分, 共15道小题, 总分值60分)1.beef teaA. 牛肉茶B. 牛肉汁答案：B 答案联系“文档贡献者”2.Not a sound reached our ears.A. 我们没有听到任何声音。

B. 我听到了一点声音。

答案：A3.种瓜得瓜，种豆得豆。

A. As you sow , so will you reap.B. As you sow, so you will reap.答案：A4.The most of the Panamanians who are after at this time is a chance to get more income from the Canal.A. 最多的巴拿马人现在追求的是寻找机会从运河获得更多的收入B. 当前巴拿马人所追求的是争取从运河得到更多的收入。

答案：B5.all corners of the countryA. 一个国家的每一处地方B. 五湖四海答案：B6.There is no untroubled place in this troubled world.A. 这多灾多难的世界有太平的乐土。

B. 这多灾多难的世界没有任何太平的乐土。

7.酒醉智昏。

A. When wine is in , wit is out.B. When wine is drunk,wit is out.8.with great eagernessA. 如饥似渴B. 望眼欲穿9.They were news hungry.A. 他们迫切想弄到消息。

B. 他们对消息很敏感。

10.他妹妹老是说谎。

A. His sister always tells liesB. His sister is a great liar.11.We gave him some good advice, but he made light of it.A. 我们给他忠告，但他不当一回事。

大物AI作业参考解答_No.04 机械能机械能守恒定律

k ，以
此位置作为重力势能 0 点，根据机械能守恒：
mg(h
x)
1 2
mv 2 max
1 2
kx2
，将
x
mg k
代入得到
1 2
mv 2 max
mg h
mg k
1 2
k
mg k
2
mgh
m2 g 2 2k
10．一个作直线运动的物体，其速度 v 与时间 t 的关系曲线如图所示。 v
设时刻 t1 至 t2 间外力作功为W1 ；时刻 t2 至 t3 间外力作的功为W2 ；时刻
答：（1）守恒。因为整个系统，外力的功为零，非保守内力是小球与管壁的作用力与反作用力 N 和 N 。
在小球下滑过程中，小球受壁的压力 N 始终与管壁垂直，也始终与小球相对管壁的速度方向垂直，所
以 N 和 N 作功为零，满足机械能守恒。
（2）不守恒。小球在下落过程中，受到重力和管壁的作用力，这两个力的合力不为零，所以小球的动量会不断变化。
4.保守力做功的特点是作功大小与路径无关，只与初末位置有关，沿闭合路径作功的大小为零；保守力作功等于其相关势能增量的负值，保守力等于其相关势能函数梯度的负值。
5.对于一个系统来说，动量守恒的条件是合外力为零，角动量守恒的条件是外力矩之和为零，机械能守恒的条件是外力作功与非保守内力作功之和为零。
3.一个内壁光滑的圆形细管，正绕竖直光滑固定轴 OO 自由转动。管是刚性的，转
动惯量为 J。环的半径为 R，初角速度为 0 ，一个质量为 m 的小球静止于管内最高
点 A 处，如图所示，由于微扰，小球向下滑动。试判断小球在管内下滑过程中：（1）地球，环与小球系统的机械能是否守恒？（2）小球的动量是否守恒？（3）小球与环组成的系统对 OO 轴的角动量是否守恒？回答让述问题，并说明理由。

环境化学作业题解答

5
2、逆温现象对大气中污染物的迁移有什么影响?
一般情况下，大气温度随着高度增加而下降，每上升100 米，温度降低0.6℃左右。即是说在数千米以下，总是低层大气温度高、密度小，高层大气温度低、密度大，显得 “头重脚轻”。这种大气层结容易发生上下翻滚即“对流” 运动，可将近地面层的污染物向高空乃至远方输散，从而使城市上空污染程度减轻。因而在通常情况下，城市上空为轻度污染，对人体健康影响不大。可是在某些天气条件下，一地上空的大气结构会出现气温随高度增加而升高的反常现象，从而导致大气层结“脚重头轻”，气家学家称之为“逆温”，发生逆温现象的大气层称为“逆温层”。它像一层厚厚的被子罩在我们城乡上空，上下层空气减少了流动，近地面层大气污染物“无路可走”，只好原地不动，越积越多，空气污染势必加重。
（2）含氮化合物
氧化亚氮(N2O)、一氧化氮(NO)和二氧化氮(NO2)。N2O是低层大气含量最高的含氮化合物，由于其非常稳定，一般认为其没有明显的污染效应。 NOX来源与消除：NO和N02是大气中主要含氮污染物。其人为来源是燃料燃烧。燃烧源分为流动和固定燃烧源。城市大气中NOX 2/3来自汽车排放，1/3来自固定源排放。燃烧产生的NOX主要是NO，占90％以上；NO2 约占O.5％～10％。大气中NOX最终将转化为硝酸和硝酸盐微粒经湿沉降和干沉降从大气中去除，其中湿沉降是最主要的消除方式。
③中间层： 50～80km；空气较稀薄；臭氧层消失；温度随海拔高度的增加而迅速降低；大气的垂直对流强烈。 ④热层：80～500km；在太阳紫外线照射下空气处于高度电离状态（电离层），能反射无线电波，人类可利用它进行远距离无线电通讯；大气温度随高度增加而升高；空气更加稀薄，大气质量仅占大气总质量的 0．5％。热层以上的大气层称为逃逸层。这层空气在太阳紫外线和宇宙射线的作用与大气温度不同，大气的压力总是随着海拔高度的增加而减小。

英语作业4

单选题（分数：25分）得分：241.—Hello, may I talk to the director now? —________1.Sorry, he is busy at the moment.2.No, you can’t.3.Sorry, you can’t4.I don’t know.2.—I was worried about my maths, but Mr. Brown gave me an A. —________1.D on’t worry about it.2.Congratulations! That’s a difficult course.3.Mr. Brown is very good.4.Good luck to you!3.—What can I do for you? —________1.I want a kilo of pears.2.You can do in your own way.3.Thanks.4.Excuse m e. I’m busy.4.—Excuse me, but can you tell me the way to the post office? —________1.Don’t ask that.2.Sorry, I’m a stranger here.3.No, I can’t say that.4.No, you’re driving too fast.5.—Oh, sorry to bother you. —________1.Th at’s Okay.2.No, you can’t.3.That’s good.4.Oh, I don’t know.6.—Who’s that speaking? —This is Tom ________1.speaks2.spoken3.speaking4.saying7.—I’m sorry. I lost the key. —________1.Well, it’s OK.2.No, it’s all right.3.You are welcome.4.You are wrong.8.—It’s rather cold in here. Do you mind if I close the window? —________1.Yes, please.2.No, go ahead.3.Sure, please.4.I don’t like it.9.—________ —He teaches physics in a school.1.What does your father want to do?2.Who is your father?3.What is your father?4.Where is your father now?10.—Excuse me, how much is the jacket? —It’s 499 Yuan. ________.1.Oh, no. That’s OK!2.How do you like it?3.Which do you prefer?4.Would you like to try it on?11.—You know, I have three kids now. —________1.Well, I’ve grown a mustache.2.That’s terrific!3.Say, you’ve really changed your hair.4.Well, I gave up drinking.12.—How about going to dinner at the Mexican restaurant tonight? —________1.Forget it.2.Sorry, I like Mexican food.3.That’s great!4.Glad you like it.13.—How are you, Bob? —________ Ted.1.How are you?2.I’m fine. Thank you.3.How do you do?4.Nice to meet you.14.—Thanks for your help. —________1.My pleasure.2.Never mind.3.Quite right.4.Don’t thank me.15.—Hello, I’m Harry Potter. —Hello, my name is Charles Green, but ________.1.call my Charles2.call me at Charles3.call me Charles4.call Charles me16.—Paul, ________? —Oh, that’s my father! And beside him, my mother.1.what is the person over there2.who’s talking over there3.what are they doing4.which is that17.—Hi, Tom, how’s everything with you? —________, and how are you?1.Don’t mention it2.Hm, not too bad3.Thanks4.Pretty fast18.—That’s a beautiful dress you have on! —________1.Oh, thanks. I got it yesterday.2.Sorry, it’s too cheap.3.You can have it4.See you later.19.—Why didn’t you come to my birthday party yesterday? —________1.Excuse me, my friend sent me a flower.2.Fine, I never go to birthday parties.3.Ha…ha, I don’t like birthday parties.4.Sorry, but my wife had a car accident20.—Hi, welcome back! Had a nice trip? —________1.Oh, fantastic! Fresh air, and sunshine every day.e on, I’ve got lots of fun.3.By the way, I don’t like Saturdays.4.Well, I’ll look forward to your phone call.21.—Haven’t seen you for ages! What are you busy doing now? —________1.I hate the weather here.2.My hair is getting a bit longer.3.Yeah, thanks for coming.4.I am working part time in a bookshop, you know.22.—Marilyn, I’m afraid I have to be leaving now. —________1.That sounds wonderful.2.Oh, so early?3.Not at all.4.Good luck!23.— Good morning, John . How are you doing? — ________1.I'm pleased.2.Good night.3.Not so bad. And you?4.How do you do?24.— How do you do? — ________1.Fine, thank you.2.How do you do?3.Not too bad.4.Very well.25.— Good— bye for now. —________1.The same to you.2.That's OK.3.See you.4.Long time no see.。

人教版初中英语7年级下册unit4知识清单+习题 (附解答)

Unit 4 Don't eat in class一、必记单词rule n．规则；规章arrive v到达listen v听；倾听fight v＆n．打架；战斗outside adv在外面adj外面的wear v穿；戴important adj．重要的bring v带来；取来quiet adj安静的practice v＆n．练习before prep．conj．在……以前adv．以前dirty adj脏的kitchen n厨房noisy adj．吵闹的relax v放松；休息read v读；阅读terrible adj非常讨厌的；可怕的feel v感受；觉得strict adj严格的；严厉的remember v记住；记起follow v遵循；跟随luck n．幸运；运气keep v保持；保留learn v学习；学会hall n 大厅，礼sorry adj.抱歉的，难过的，惋惜的dish n.碟，盘more adj.&pron.更多的hair n.头发，毛发二、常考短语（be）on time准时listen to．．听…….have to必须；不得不do the dishes 清洗餐具go out 外出（娱乐）make one’s bed铺床be strict（with sb．）（对某人）要求严格follow the rules遵守规则in class 在课上be late for做…迟到be quiet安静make breakfast做早饭keep one’s hair short留短发play with sb．和某人一起玩play the piano弹钢琴have fun玩得开心make rules 制订规则dining hall餐厅eat outside在外面吃东西wear the school uniform穿校服Don＇t＋动词原形＋其他．不要做某事help sb．（to）do sth．帮助某人做某事too many＋可数名词复数太多的…practice doing sth．练习做某事leave＋sth．＋地点状语把某物忘在某地must＋动词原形必须做某事keep＋宾语＋形容词使……保持某种状态learn to do sth．学会做某事have to do sth．不得不做某事bring sb./sth．to＋地点把某人／某物带到某地三、经典句型1.Don＇t arrive late for class．上课不要迟到。

2017版《红对勾讲与练》人教版化学选修4：课时作业4 Word版含解析

课时作业4燃烧热能源时间：45分钟满分：100分一、选择题(每小题4分，共48分)1．燃烧热与反应热的关系是()A．燃烧热是反应热的一种类型B．当一个反应是燃烧反应时，该燃烧反应的反应热就是燃烧热C．燃烧热不属于反应热，反应热是在25 ℃、101 kPa下测定的，而燃烧反应的温度要高D．反应热有正负之分，燃烧反应的焓变全部是正值解析：可燃物是1 mol 时的反应热才是燃烧热。

答案：A2．已知：①2H2O(g)===2H2(g)＋O2(g)ΔH＝＋483.6 kJ·mol－1②H2S(g)===H2(g)＋S(g)ΔH＝＋20.1 kJ·mol－1下列判断正确的是()A．氢气的燃烧热：ΔH＝－241.8 kJ·mol－1B．相同条件下，充分燃烧1 mol H2(g)与1 mol S(g)的混合物比充分燃烧1 mol H2S(g)放热多20.1 kJC．由①②知，水的热稳定性小于硫化氢D．②中若生成固态硫，ΔH将增大解析：由①可知，H2(g)＋12O2(g)===H2O(g)ΔH＝－483.6 kJ·mol－1×12＝－241.8 kJ·mol－1，故氢气的燃烧热是241.8 kJ·mol－1，②表示的是1 mol H2S(g)所含有的能量比1 mol H2(g)与1 mol S(g)的混合物所含有的能量少20.1 kJ，故相同条件下，充分燃烧1 mol H2(g)与1 mol S(g)的混合物比充分燃烧1 mol H2S(g)放热多20.1 kJ，B项正确；由①②知，水分解比硫化氢分解要多吸收能量，即水不易分解，说明水的稳定性大于硫化氢，C项错误；由于S(g)→S(s)，要放热，故②中若生成固态硫，ΔH将减小，D项错误。

答案：B3．“能源分类相关图”如图所示，下列四组能源选项中全部符合图中阴影部分的能源是()A．煤炭、石油、潮汐能B．水能、生物能、天然气C．太阳能、风能、沼气D．地热能、海洋能、核能解析：太阳能、风能、沼气这三种能源既是新能源、可再生能源，而且是来自太阳的能源。