第十五章习题答案final

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基础英语15单元课后习题答案

基础英语15单元课后习题答案基础英语（一）课后释义及翻译答案Unit 1Paraphrase:1.Our big old house was touched with the laughter and tears of four generations.Our big old house had seen the joys and sorrows of four generations of our family.2.I planted these roses a long, long time ago—before your mother was even adream.I planted these roses a long, long time ago, before your mother was born.3.Many sons went away to fight a great evil.Many sons left home to fight against the fascists.4.Take that special hello and lock it away within you.Take the first friendly greeting and always keep it deep in your heart.Translation:1.他对这次面试中可能提到的问题作好了准备。

(confront)He has prepared answers to the questions that he expects to confront during the interview.2.他悲惨的遭遇深深打动了我们，使我们几乎哭出声来。

(touch)His sad story touched us so deeply that we nearly cried.3.他们俩手挽着手沿着河边散步，有说有笑。

大学英语精读3Unit15课后习题题目及答案翻译

Unit 11）From her accent I guess she’s from the Northeast.2）It was very clever of her to turn his argument against himself.3）I found a couple of shoes under the bed but they don’t make a pair.4）Dr. Bright always take his time as he examines his patients and treats them with extreme care. 5）British companies are trying to avoid the fate their American counterparts have already suffered.6）Wilfred’s remarks confirmed me in my opinion that he was an honorable(诚实的) young man.7）The key witness for the prosecution(原告方) was offered police protection after she received death threats.8）I thought that was the end of the matter but subsequent events proved me wrong.9）Having practiced for so long, the New Y ork baseball team stand a chance of winning the World Series (美国职业棒球大赛) this year.10）At the trial ,Bob’s teacher, who was called as a character witness , said he was a quiet boy who had never been in trouble before.Unit1 翻译1) 发言人（spokesman）明确表示总统在任何情况下都不会取消（cancel）这次旅行。

人教版U15 Final Test含参考答案

FINAL TESTA Listening Comprehension Listen to the conversation and underline the correct answers. Each correct answer counts for two points．Example：Who was worried about missing the plane?a．the son b．the father c．the mother1．Who had already put a suitcase in the car?a．the son b．the father c．the mother 2．What was Mom doing when Mike asked if she was ready?a．talking on the telephone b．cleaning the living room c．watering the plants 3．What was one thing Mike was going to do in the house?a．lock the doors b．make sure the lights were turned off c．clean up 4．What was Mike going to do with his bicycle?a．ride it b．put it away c．put it on top of the car 5．What else was Mike going to do in the house?a．look at the oven b．put the dishes away c．do the dishes6．What has the mother already done?a．made the beds b．bought food c．shopped for clothes 7．What happened while the mother was cleaning the living room?a．A visitor came. b．The telephone rang. c．A UFO landed．8．What did Mom forget to do after she talked to grandmother?a．cook dinner b．go back into the living room c．pack her suitcase 9．What did the son find in the living room?a．the plane tickets b．his bicycle c．a pizza10．Where is the family going?a．on vacation b．to the movies c．to grandmother's houseB Vocabulary Fill in the blanks with the words from the box. Each correct answer counts for two points．Example：Do you have a microwave in your kitchen?1．Do you know why the manatee is an ________________ animal?2．I am afraid I'm going to ________________ the test for my driver's license．3．Those sunglasses make you look ________________．4．Do you ever listen to English language ________________?5．I would like to ________________ to work in the hospital with sick children．6．I prefer singers who write their own ________________, don't you?7．I'm looking for Tony's house, but this ________________ is hard to read．8．When I came into class late, everyone looked at me, and the teacher was angry. I felt so ________________．9．I've learned that it's ________________ to shake hands when you meet someone in the United States．10．I have studied ten hours for the science test. I feel ________________ that I will get a good grade．C Functions Match the questions and answers in conversations. Each correct answer counts for two points．Example： d Why do you think zoos are bad for animals?1．__________ Have you turned off all the lights?2．__________ How does exercise make you feel?3．__________ Is it polite to arrive for dinner early at your house?4．__________ Excuse me. Where is the soap?5．__________ Would you mind telling me where I can exchange some money? 6．__________ When was the telephone invented?7．__________ What happened after you ordered the pizza?8．__________ Do you want to learn a new language while you're on vacation? 9．__________ Who is the reporter?10．_________ What kind of sandwich do you prefer?a．Yes, I turned them all off．b．No, you should arrive a few minutes late．c．Sure. There is a bank across the street. They can help you．d．They keep animals in cages that are too small．e．After I ordered my food, an alien walked into the restaurant．f．No, thanks. I just want to relax in the mountains．g．The reporter is the woman who is wearing a red blouse and skirt．h．I think it was invented in 1876．i．I prefer a turkey sandwich．j．Go to the end of the aisle. Turn left and go down the next aisle. The soap is on the right．k．It always makes me energetic．D Grammar Underline the correct words or phrases in the parentheses. Each correct answer counts for two points．Example：We （tried / trying）to help the environment by picking up trash．1．The manatee's swamps are （polluted / become polluted）．2．I've （pack / packed）my suitcase. What else should I do?3．The loud music in this restaurant （made / makes）me nervous. Let's go home．4．（Do you know / Could you please tell me how）to buy a ticket for the subway? 5．When was tea （used for / invented）?6．By the time the alarm went off, I knew I had （overslept / oversleep）．7．By the time I got into the shower, the water （is / was）already cold．8．I've run out of signs about （clean up / cleaning up）the streets in our city．9．I'd （love / hope）to go to the movies with you tomorrow. Thanks!10．I like movies （that / who）are romantic．E Reading and Writing Answer the questions in complete sentences. Each correct answer counts for two points．Example：What kind of teachers do you prefer?I like teachers who are energetic．1．Will you send your friend a thank-you note?_______________________________________________________________ 2．Why do you think that practicing conversations helps you learn English?_______________________________________________________________ 3．What is something that teenagers shouldn't be allowed to do?_______________________________________________________________ 4．What would you do if you had to give a speech to your English class?_______________________________________________________________ 5．Where would you enjoy eating dinner?_______________________________________________________________ 6．When do you talk on the telephone?_______________________________________________________________ 7．What happened by the time you got to the basketball game?_______________________________________________________________ 8．Could you tell me if there are any good restaurants near your home?_______________________________________________________________ 9．How are you supposed to be polite in Japan when you meet someone?_______________________________________________________________ 10．What could students recycle at your school?_______________________________________________________________ Answers:Final TestA Listening Comprehension1.a2.c3.b4.b5.a6.a7.b8.b9.a 10.aB Vocabulary1.endangered2.fail3.mysterious4.cassettes5.volunteer6.lyrics7.street map 8.embarrassed 9.polite 10.confidentC Functions1.a2.k3.b4.j5.c6.h7.e8.f9.g 10.iD Grammar1.polluted2.packed3.makes4.Could you please tell me how5.invented6.overslept7.was8.cleaning up9.love 10.thatE Reading and WritingAnswers will vary.。

金融学第十五章课后答案翻译

第十五章课后答案翻译1.a.如果你持有多头：价值为s的股票为基础资产发行的，执行价格为E的欧式卖出期权的收益曲线为：b. 如果你持有空头：价值为s的股票为基础资产发行的，执行价格为E的欧式卖出期权的收益曲线为：2．持有一份欧式卖出期权和一份欧式买入期权的投资组合的收益图（E＝100）：3．a ．为了保证你至少能够收回你初始的一百万美元，你需要投资在till 股票上。

你可以购买的期权。

104股指的报酬线斜率是4807.69，正如图表所显示的。

B ．4．a.要复制一个面值为100美元的纯贴现债券，应买一份股票：其欧式买入期权价格和欧式卖出期权价格均为100。

b. S = $100, P = $10, and C = $15.46.538,961$04.1000,000,1$1000,000,1$=+=+f r 69.4807854.461,38$10008.46.538,961$000,000,1$==⨯-E/(1+r) = S + P- C$100/(1+r) = $100 + $10 - $15 = $95r = 100/95 -1 =0 .053 or 5.3%c.如果1年期无风险利率小于b的答案，则说明纯贴现债券的价格过高，人们便会通过便宜购买综合性产品（一份其欧式买入期权价格和欧式卖出期权价格均为100的股票）来替换价格较高的纯贴现债券以从中套利。

5．用P = -S + E/(1+r)T + C这个表达式来表示卖出期权S是股价，P是卖出的执行价，C是买入期权的价格，E是执行价格，既然政府债券是以9855日元每10000日元的价格出售，这就是计算执行价格现值的贴现率，而无须用风险利率进行折现。

用平价的替代等式来计算，我们可以得到：P = -2,400 + 500 x .9855 +2,000 = 92.75 yen6．a.根据卖出－买入平价，Gekko投资组合中买入期权的价格：C = S -E/(1+r)T + P = $215 -$50 ×0 .9901 + $25 = $190.495b. Gekko的投资组合的总价值：10 x $990.10 + 200 x $190.495 = $48,000，而300股股票的总价值：$64,500。

九年级Unit15课文总结及同步练习题附答案

Unit 15 We’re trying to save the manatees!学习目标：学会表达自己的观点，并有充足的论据做支持。

培养学生的辩论及交流协作的能力。

学会正确处理人与自然的关系。

一、词汇（一）基础词汇manatee (海牛)cheetah (猎豹)kangaroo (袋鼠) chimpanzee(黑猩猩)recycle (再循环；回收利用) aquatic (水生的；水栖的) habitat (动植物的生境；栖息地) gentle (温和的；文雅的) aggressiv e (侵犯的；挑衅的) playful (好玩的；有趣的) furry (毛皮的；似毛皮的；毛皮制的) gray (灰色的；偏灰色的) enormous (巨大的；庞大的) strong (强壮的；强大的) spotted(有斑点的；有点子的)underwater (在水下的；在水中的) mangrove (红树；红树林)vegetation (植物；草木的总称) swamp (沼泽；沼泽地)be made from(由……制成；由……构成) environment(环境；生态环境；自然环境) educate (教育；培养)public (公众的；民众的)politely (礼貌地；客气地) African elephant(非洲象) feed (牧草；饲料) foot (英尺) weigh (称；称……的重量) pound (磅) against (反对；违反) suitable (合适的；适宜的) tiny (极小的；微小的) cage (笼子；囚笼) care for (关怀；照顾) urge (强烈要求；竭力主张) stuff (废物；无用的东西) material (材料；原料) pull down(摧毁；推翻) save (解救；挽救)glue (胶合；粘贴；粘合)roof (屋顶；房顶)discard(丢弃；放弃)tile (瓦片；瓷砖)fence (栅栏；围墙) inspiration (灵感；鼓舞人心的人或事物)spare (多余的；空闲的)can (金属罐)（二）重点短语1．care for 关怀，照顾2．pull down 摧毁，推翻3．be made from 由…制成4．be like 像… 5．be endangered 濒临灭绝的6．how big 多大7．ten feet long 十英尺长8．used to 过去常常9．try to do sth 尽力做某事10．be against doing sth反对做某事11．in my life 在我的生命中12．be suitable for sb to do sth适合某人做某事13．be surprised to do sth 惊讶地做某事14．living textbooks活生生的教材15．provide sth for sb.提供某物给某人16．provide sb with sth提供给某人某物17．once a day 一天一次18．educate the public 教育公众19．take care of 照顾，照料20．agree with/ disagree with同意/不同意某事21．stop doing sth 停止做某事22．be hard to do sth做某事很困难23．recycling paper废纸回收24．turn off the lights 关灯25．hear of 听说26．come from 来自27．be made from…制成（看不出原材料）28．win an award获奖29．in one’s spare time 在某人的空闲时间30．raise money 捐钱二、日常用语1. manatees are gentle. 海牛很温顺。

【练习】北师大版高中英语必修五Unit15Learning基础练习及答案

【关键字】练习再接再厉（课后巩固类训练）●Elementary exercises（基础题）Ⅰ. Multiple choice（单项选择）1. Today’s __________ in English is to write a book report.A. appreciationB. assumptionC. assignmentD. acquirement答案：C 作业、任务。

2. We have no __________ to the Internet now, for there is something wrong with Net services.A. accessB. approachC. angleD. arrow答案：A 无法上网。

access指得到某物或服务的机会或方式。

approach指做某事的具体方法。

比如有网络服务，我们才能有access to the Internet，而具体上网的approach 就是输入网址等步骤。

3. This store has an excellent __________ for fair dealing.A. receiverB. religionC. reflectionD. reputation答案：D 因为买卖公平而获得好名声。

4. The man was __________ with making too much noise late into the night.A. chargedB. accusedC. suspectedD. reminded答案：A A、B、C项都有“控告”的意思，其中B、C项都是与of搭配，只有charge 与with搭配。

5. She felt __________ only when both doors were locked.A. secureB. slightC. blankD. beneficial答案：A 只有两个门都锁了，才觉得安全。

(华师大版)初中数学八年级上册第15章综合测试01含答案解析

加油！有志者事竟成答卷时应注意事项１、拿到试卷，要认真仔细的先填好自己的考生信息。

２、拿到试卷不要提笔就写，先大致的浏览一遍，有多少大题，每个大题里有几个小题，有什么题型，哪些容易，哪些难，做到心里有底；３、审题，每个题目都要多读几遍，不仅要读大题，还要读小题，不放过每一个字，遇到暂时弄不懂题意的题目，手指点读，多读几遍题目，就能理解题意了；容易混乱的地方也应该多读几遍，比如从小到大，从左到右这样的题；４、每个题目做完了以后，把自己的手从试卷上完全移开，好好的看看有没有被自己的手臂挡住而遗漏的题；试卷第１页和第２页上下衔接的地方一定要注意，仔细看看有没有遗漏的小题；５、中途遇到真的解决不了的难题，注意安排好时间，先把后面会做的做完，再来重新读题，结合平时课堂上所学的知识，解答难题；一定要镇定，不能因此慌了手脚，影响下面的答题；６、卷面要清洁，字迹要清工整，非常重要；７、做完的试卷要检查，这样可以发现刚才可能留下的错误或是可以检查是否有漏题，检查的时候，用手指点读题目，不要管自己的答案，重新分析题意，所有计算题重新计算，判断题重新判断，填空题重新填空，之后把检查的结果与先前做的结果进行对比分析。

亲爱的朋友，你们好!经过两个月的学习，你们一定有不小的收获吧，用你的自信和智慧，认真答题，相信你一定会闯关成功。

相信你是最棒的！第15章综合测试一、选择题（每小题3分，共30分）1.某同学要统计本校图书馆最受学生欢迎的图书种类，以下是排乱的统计步骤：①从扇形图中分析出最受学生欢迎的种类；②去图书馆收集学生借阅图书的记录；③绘制扇形图来表示各个种类所占的百分比；④整理借阅图书记录并绘制频数分布表.正确统计步骤的顺序是（）A.②→③→①→④B.③→④→①→②C.①→②→④→③D.②→④→③→①2.某校提倡“绿色出行”活动，对该校学生上学方式情况进行调查，将调查结果制作成扇形统计图，如图1，可知该校（）去上学的学生最少.图1图2图3A.乘公交车B.骑车C.步行D.私家车3.为了直观的表示济宁市高考和中考期间的最高气温变化情况，最适合使用的统计图是（）A.条形统计图B.扇形统计图C.折线统计图D.直方图4.小红6月份各项消费情况的扇形统计图如图2所示，其中小红在学习用品上共支出120元，则她在午餐上共支出（）A.120元B.180元C.240元D.300元5.在进行数据统计时，选取了20个数据进行分组分析，其中某个小组有4个数据，则该小组对应的扇形统计图的圆心角度数为（）A.36︒B.72︒C.60︒D.120︒6.小明家1至6月份的用水量统计如图3，则5月份的用水量比4月份增加的百分率为（）A.20%B.25%C.50%D.33%7.某旅游城市为向游客介绍本地的气温情况，绘制了一年中月平均最高气温和平均最低气温的雷达图，如图4，图中A点表示十月的平均最高气温约为15℃，B点表示四月的平均最低气温约为5℃.下面叙述不正确的是（）图4图5A.各月的平均最低气温都在0℃以上B.七月的平均温差比一月的平均温差大C.三月和十一月的平均最高气温基本相同D.平均气温高于20℃的月份有5个8.在某校选拔毕业晚会主持人的决赛中，参与投票的每名学生必须从进入决赛的四名选手中选1名，且只能选1名，根据投票结果，绘制了（如图5）两幅不完整的统计图，则选手B的得票为（）A.300B.90C.75D.859.5G网络是第五代移动通信网络，它将推动我国数字经济发展迈上新台阶.据预测，2020年到2030年中国5G直接经济产出和间接经济产出的情况如图6，根据图中提供的信息，下列推断不合理的是（）A.2030年5G间接经济产出比5G直接经济产出多4.2万亿元B.2020年到2030年，5G直接经济产出和5G间接经济产出都是逐年增长C.2030年5G直接经济产出约为2020年5G直接经济产出的13倍D.2022年到2023年与2023年到2024年5G间接经济产出的增长率相同图610.在某次数学测试中，满分为100分，各测试内容及所占分值的分布情况如图7所示扇形统计图，有以下结论：①一元一次不等式（组）部分与二元一次方程组部分所占分值一样；②因式分解部分在试卷上占10分；③整式的运算部分在整张试卷中所占比例为25%；④观察、猜想与证明部分的圆心角度数为72°.其中正确的是（）图7A.仅①②③B.①②③④C.仅②③④D.仅①④二、填空题（每小题3分，共18分）11.已知小鹏家五月份总支出共计3600元，用扇形统计图表示时，教育支出所在的扇形的圆心角是108︒，那么其中用于教育上的支出是________元.12.小明将同学们周末生活的调查结果绘制成了如图8所示的扇形统计图.其中，看书这一项对应的圆心角度数为72︒，则周末看书的同学人数占了总数的________.（填百分比）图8图9图1013.如图9是北京故宫博物馆2019年国庆期间客流指数统计图（客流指数是指景区当日客流量与2019年10月1日客流量的比值）.根据图中信息，不考虑其他因素，如果小宇想在今年国庆期间游客较少时参观故宫，最好选择10月________日参观.14.如图10的折线统计图分别表示A县和B县在4月份的日平均气温情况，记该月A县和B县日平均气温+=________.是12℃的天数分别为a天和b天，则a b15.在“童心向党，阳光下成长”的合唱比赛中，30个参赛队的成绩被分为5组，第1～4组的频数分别为2，10，7，8，则第5组的频率为________.16.已知10个数据：0，1，2，3，6，1，2，3，0，3，其中2出现的频数为________.三、解答题（共52分）17.（8分）如图11，下面是甲、乙两校男、女生人数的统计图.图11根据统计图回答问题：（1）若甲校男生人数为273人，求该校女生人数；（2）方方同学说：“因为甲校女生人数占全校人数的40%，而乙校女生人数占全校人数的45%，所以甲校的女生人数比乙校女生人数少”，你认为方方同学说得对吗？为什么？18.（8分）为响应国家的一带一路经济发展战略，树立品牌意识，某市质检部分别对A ，B ，C ，D 四个厂家生产的同种型号的零件（共2000件）进行合格率检测，通过检测得出C 厂家的合格率为95%，并根据检测数据绘制了（如图12）两幅不完整的统计图：图12（1）抽查D 厂家的零件为________件，扇形统计图中D 厂家对应的圆心角为________度；（2）抽查C 厂家的合格率零件为________件，并将图11中的条形统计图补充完整；（3）通过计算说明A ，C 两厂家谁的合格率更高？19.（8分）有一道满分12分的解答题，按评分标准，所有考生的得分只有四种：0分，4分，8分，12分.老师为了了解学生的得分情况与题目的难易情况，从所有考生的试卷中随机抽取一部分，通过分析与整理，绘制了两幅不完整的统计图，如图13：图13请根据以上信息解答下列问题：（1）填空：a =________，b =________，并把条形统计图补全；（2）已知难度系数的计算公式为WXL =，其中L 为难度系数，X 为平均得分，W 为试题满分值.一般来说，根据试题的难度系数可将试题分为以下三类：当00.4L ≤≤时，此题为难题；当0.40.7L ＜≤时，此题为中等难度试题；当0.71L ＜≤时，此题为容易题.试问此题对于这些考生来说属于哪一类？请说明理由.20.（9分）课外阅读是提高学生素养的重要途径.某中学为了了解全校学生课外阅读情况，随机调查了200名学生，统计他们平均每天课外阅读时间（小时）.根据每天课外阅读时间的长短分为A，B，C.D四类，下面是根据所调查的人数绘制的两幅不完整的统计图表，如图14，请根据图中提供的信息，解答下面的问题：200名学生平均每天课外阅读时间条形统计图类别时间t（小时）人数t＜40A0.5B0.51t≤＜80C1 1.5t≤＜60D 1.5t≥a200名学生平均每天课外阅读时间统计表图14（1）求表格中a的值；（2）并在图中补全条形统计图：（3）请你根据上述信息对该校提出相应的建议.21.（9分）某校九年级部分同学参加了一次内容为“最喜欢的课间餐水果”的调查活动，收集整理数据以后，老师将水果分为五类，并绘制了（图15）两幅不完整的统计图，请根据图中信息解答下列问题：图15根据统计图中的信息，解答下列问题：（1）求本次被调查的学生人数；（2）将条形图补充完整；（3）在扇形统计图中，求杨梅所占扇形的圆心角度数.22.（10分）安全使用电瓶车可以大幅度减少因交通事故引发的人身伤害，为此交警部门在全市范围开展了安全使用电瓶车专项宣传活动.在活动前和活动后分别随机抽取了部分使用电瓶车的市民，就骑电瓶车戴安全帽情况进行问卷调查，将收集的数据制成如（图16）所示统计图表.图16（1）宣传活动前，在抽取的市民中哪一类别的人数最多？占抽取人数的百分之几？（2）小明认为，宣传活动后骑电瓶车“都不戴”安全帽的人数为178，比活动前增加了1人，因此交警部门开展的宣传活动没有效果.小明分析数据的方法是否合理？请结合统计图表，对小明分析数据的方法及交警部门宣传活动的效果谈谈你的看法.第15章综合测试答案一、1.【答案】D 2.【答案】D 3.【答案】C 4.【答案】C 5.【答案】B 6.【答案】A 7.【答案】D 8.【答案】C 9.【答案】D 10.【答案】B 二、11.【答案】108012.【答案】20%13.【答案】714.【答案】1215.【答案】0.116.【答案】2三、17.【答案】解：（1）因为甲校中男生有273人，占60%，所以总人数为：27360%455÷=（人），则女生有455273182-=（人）.（2）不对.因为甲、乙两校的总人数不一定相同，所以没法比较人数的多少.所以方方同学说得不对.18.【答案】（1）50090（2）380（3）解：A 厂家合格率()630200035%90%=÷⨯=，C 厂家合格率95%=，所以合格率更高的是C 厂家.【解析】（1）()135%20%20%200025%2000500---⨯=⨯=.()135%20%20%36090---⨯︒=︒.故答案为：500，90.（2）20%200095%380⨯⨯=.故答案为：380.补全统计图，如图1：图1（3）详细解答过程见答案.19.【答案】（1）2520（2）因为024460810812487240X ⨯+⨯+⨯+⨯==，所以08712.533L =≈.所以此题对于这些考生来说属于中等难度试题.【解析】解：（1）因为被调查的总人数为2410%240÷=（人），所以48240%100%20%b =⨯=，则()%110%20%45%25%a =-++=.所以4分的人数为24025%60⨯=（人）.补全统计图，如图2：图2故答案为：25，20（2）详细解答过程见答案.20.【答案】（1）20040806020---=（名），故a 的值为20.（2）补全统计图如图3：图3（3）合理即可.如：课外活动应该多增加阅读量和多运动.21.【答案】解：（1）6030%200÷=（人）.答：本次调查的学生有200人.（2）喜欢香蕉的学生有：20015%30⨯=（人），喜欢杨梅的学生有：2002460301670----=（人）.补全的统计图如图4；图4（3）︒=︒⨯++++126360163060702470.答：杨梅所占扇形的圆心角度数为136°.22.【答案】解：（1）宣传活动前，在抽取的市民中偶尔戴的人数最多，占抽取人数：510100%51%1000⨯=.答：宣传活动前，在抽取的市民中偶尔戴的人数最多，占抽取人数的51%.（2）宣传活动后骑电瓶车“都不戴”安全帽的百分比：8.9%%100178224702896178=⨯+++.活动前全市骑电瓶车“都不戴”安全帽的百分比：177100%17.7%1000⨯=.因为8.9%17.7%＜，所以交警部门开展的宣传活动有效果.。

_人教版八年级上册第十五章测试题含答案

15.1《分式》一．选择题1．下列式子：﹣5x，，，，，其中分式有（）A．1个B．2个C．3个D．4个2．若分式的值为0，则x的值是（）A．0B．1C．2D．﹣13．要使分式有意义，x的取值应满足（）A．x≠2B．x≠﹣3C．x≠2且x≠﹣3D．x≠2或x≠﹣3 4．下列分式中，最简分式是（）A．B．C．D．5．若分式中x、y的值同时扩大到原来的5倍，则分式的值（）A．不变B．是原来的C．是原来的5倍D．是原来的25倍6．化简的结果是（）A．B．C．D．7．若分式的值为正数，则x的取值范围是（）A．x＞B．x＜C．x≥D．x取任意实数8．分式和的最简公分母是（）A．6y B．3y2C．6y2D．6y3二．填空题9．当x时，分式有意义．10．已知分式的值等于0，则x＝．11．化简＝．12．在分式.，，，中，最简分式有个．13．若把分式中的x，y都扩大5倍，则分式的值．14．将，通分可得．15．如果分式﹣的值为负数，则y的取值范围是．16．分式的最简公分母是．三．解答题17．已知分式，回答下列问题．（1）若分式无意义，求x的取值范围；（2）若分式的值是零，求x的值；（3）若分式的值是正数，求x的取值范围．18．通分（1），（2），（3），（4），19．约分：（1）（2）20．约分：（1）（2）21．约分：（1）（2）（3）22．已知a，b，c均是非零有理数，请完成下面的探索：（1）试求的值；（2）试求+的值；（3）请直接写出++的值．参考答案一．选择题1．解：，的分母中含有字母，属于分式，共有2个．故选：B．2．解：分式的值为0，则x﹣1＝0，且2x≠0，解得：x＝1．故选：B．3．解：由题意可知：x+3≠0，∴x≠﹣3故选：B．4．解：A、＝，则原分式不是最简分式，故此选项不合题意；B、是最简分式，故此选项符合题意；C、＝＝﹣，则原分式不是最简分式，故此选项不合题意；D、＝﹣＝﹣，则原分式不是最简分式，故此选项不合题意；故选：B．5．解：原式＝＝，故选：C．6．解：原式＝＝，故选：B．7．解：∵分式的值为正数，∴x2+5＞0，2x﹣1＞0，解得：x＞．故选：A．8．解：根据最简公分母定义可知：3和2的最小公倍数是6，字母的最高次幂是2，所以分式和的最简公分母是6y2．故选：C．二．填空题9．解：根据题意，得2x+1≠0．解得x．故答案是：．10．解：∵分式的值等于0，∴x﹣1＝0且x≠0，故x＝1．故答案为：1．11．解：＝；故答案为：．12．解：，，是最简分式，的分子分母中含有公因式（x﹣y），不是最简分式．故答案是：3．13．解：＝5，即若把分式中的x，y都扩大5倍，则分式的值扩大5倍，故答案为：扩大5倍．14．解：∵两个分式分母分别为3a，2c未知数系数的最小公倍数为3×2＝6，∵a，c的最高次数为1，∴最简公分母为6ac，将，通分可得：和．15．解：根据题意可得：2y﹣3＞0，解得：y＞1.5，故答案为：y＞1.5．16．解：＝，则最简公分母为x（x+2）（x﹣2），故答案为：x（x+2）（x﹣2）．三．解答题17．解：（1）由题意得：2﹣3x＝0，解得：x＝；（2）由题意得：x﹣1＝0，且2﹣3x≠0，解得：x＝1；（3）由题意得：①，此不等式组无解；②，解得：＜x＜1．∴分式的值是正数时，＜x＜1．18．解：（1）最简公分母：12x3y2，＝，＝；（2）最简公分母：2（a+3）（a﹣3），＝，＝；（3）最简公分母：（a﹣3）2（a+3），＝，＝；（4）最简公分母：2（a+3）（a﹣1），＝＝＝，＝＝﹣＝﹣．19．解：（1）＝；（2）＝＝．20．解：（1）＝；（2）原式＝＝．21．解：（1）原式＝＝；（2）原式＝＝m；（3）原式＝＝．22．解：（1）当a为正数时，＝＝1；当a为负数时，＝＝﹣1；（2）当a＞0，b＞0时，；当a＜0，b＜0时，；当a＞0，b＜0时，；当a＜0，b＞0时，；（3）当a＞0，b＞0，c＞0时，原式＝1+1+1＝3；当a＞0，b＞0，c＜0时，原式＝1+1﹣1＝1；当a＞0，b＜0，c＞0时，原式＝1﹣1+1＝1；当a＜0，b＞0，c＞0时，原式＝﹣1+1+1＝1；当a ＜0，b ＜0，c ＞0时，原式＝﹣1﹣1+1＝﹣1；当a ＜0，b ＞0，c ＜0时，原式＝﹣1+1﹣1＝﹣1；当a ＞0，b ＜0，c ＜0时，原式＝1﹣1﹣1＝﹣1；当a ＜0，b ＜0，c ＜0时，原式＝﹣1﹣1﹣1＝﹣3，则原式＝1，﹣1，3，﹣3．15.2分式的加减1. 填空：（1）=-++xyx x y x 22________；（2）=---y x y y x x 22________；（3）=+-+xy x y xy x y 4345________；（4）=--+-2222)()(b a b b a a ________；（5） =-+ab c b a a b 2________；（6）_______1111=-++a a ；（7）若222222M xy y x yx y x y x y--=+--+ ,则M=___________. 2.选择⑴m n nm n m m +--+2的运算结果是（） A 、m n n m +-3 B 、m n n m +--3 C 、nm n m +- D 、1⑵ 计算()aa -+-111的结果是（）A.a a -1B.a a -12C.12-a aD.()aa a --12 （3）下列运算中，错误的是（） A.y x x y y y x x -=---12222 B.423234822---=-+-a a a a C.22222y x y x y xy y x y -=-++ D.3131922-=+--a a a a （4）有理数x 、y 满足1=xy ，设y x M +++=1111，yyx x N +++=11，则M 、N 的关系是（）A.M ＞NB.M ＝NC.M ＜ND.不确定 3.计算（1）xy yy x y 61121422+- （2）)(2n m m m n m m ---（3）ba ba b a b a -+-+- （4）222222n m n m n m n m -+-+-（5）222299369x x x x x x x +-++++; （6）249152233322xx x x -+--++（7）112---a a a （8）1213223-+----x x x x x（9）)25)(5(102510125222-+-++--a a a a a a4、先计算xx ++-1111，通过以上计算，请你用一种你认为较简便的方法计算下列各式。

九年级英语第十五单元及答案

九年级新目标英语第十五单元试题Ⅰ. 单项选择。

（计15分）( ) 1. I a manatee. I water and vegetables.A. am like, am likeB. like, likeC. am like, likeD. like, am like( ) 2. There be a lot of manatees, but now they endangered animals.A. used to, becomeB. would, becomeC. used to, have becomeD. would, have become( ) 3. The well is too dangerous. We’d better or it may hurt other people.A. pull it downB. pull down itC. sit downD. sit it down( ) 4. Be careful of the dog! It’s . Keep away from it.A. gentleB. aggressiveC. lovelyD. interesting( ) 5. Do you think zoos are like textbooks for young people?A. livingB. live inC. aliveD. lived( ) 6. —What’s this scarf made? —Silk.A. ofB. fromC. inD. by( ) 7. I really don’t money.A. care forB. take care ofC. care ofD. take care( ) 8. What in that shop?A. did happenB. is happeningC. was happenedD. happen( ) 9. In the city the old .A. take good care ofB. are taken good care ofC. is taken good care ofD. are been taken good care of( ) 10. The boy was seen his bike a moment ago.A. fell offB. to fall offC. fall offD. to fall down( ) 11. I don’t know if he tomorrow. If he , I’ll ring you up.A. comes, comesB. will come, comesC. comes, will comeD. will come, will come( ) 12. We should urge people riding in cars.A. stopB. stoppingC. to stopD. stopped( ) 13. I found hard to weigh this huge stone.A. thisB. thatC. itD. those( ) 14. I don’t think that sweater is suitable _________ this hot weather.A. forB. toC. onD. about( ) 15. The old man was very what his son did.A. surprised inB. surprised toC. surprised atD. surprising atⅡ. .任务型阅读 ABreaking Bad Eating -HabitsHave you heard the expression "You are what you eat"? Well, do you like who you are'' If not, break some bad eating habits and feel better about yourself.Bad habit 1: ______________Many packaged ( = in small bags) foods, such as frozen （纤维) dumplings ,rice rolls and instant noodles (方便面) have lots of fat and calories (热量).The solution: Read the instructions to find the healthiest foods that are low in salt and nigh in fiber Also check to make sure they have ingredients such as vegetables and grains When possible, use packaged foods as part of a "home-cooked" meal. For example frozen （纤维) dumplings with fresh vegetables are better than dumplings alone.Bad habit 2:_____________________________________________People without breakfast don't have enough energy they need to get through the morning. Eating breakfast improves your concentration, memory (冰冻的）and mood.The solution: Always keep a kind of quick foods like yogurt. Or have a standing order a! breakfast place.Bad habit 3:_________________________________________________ It takes your body at least 20 minutes to "tell" your brain that you are full, So last eaters usually eat more than people who eat slowly.The solution: Try to slow down. Try eating at least some of your meals without TV, hand phones or computers. Use a plate or bowl when you eat.Bad habit 4:______________________ ______________Healthy snacks between meals are fine. But when you snack instead of having real meals, you will not eat your meals regularly. Plus, snack foods such as chips and sweets aren't very satisfying That makes it easy to overeat.The solution: To get more energy, allow yourself two healthy snacks a day. Choose snacks that will make you feel full. Try fruit, yogurt or nuts.As we all know, bad habits can be broken. Take the first step toward a healthier eating routine（常规）——start following these tips today!1. 给文中的横线处选择合适的标题,并将其字母代号填写在下面的横线上.(2分)a. You are a fast eater.b. You often don't eat breakfastc. All your meals come in packages.d. You snack too much.Bad habit 1:_____ Bad habit 2:_____ Bad habit 3:_____ Bad habit4:_______Bad habit 1:_c_ Bad habit 2:_b Bad habit 3:_a___Bad habit 4:d_______2. 列举出文中提到的三种packaged foods: (1 分)_______________ ____________________ ___________________3.根据上下文，将文中划线句子译成汉语（2分）It takes your baby at least 20 minutes to “tell” your brain that you are full.4.根据文章内容完成句子。

新概念英语第二册 Lesson15 同步习题(含答案)

新概念英语第二册同步习题Lesson15一．根据句意和汉语提示写出所缺的单词或短语。

1. The two _____ (秘书) are talking about the cooperation of the two firms.2. Tom failed the driving test again because he got ____ (紧张的) the moment he saw the coach.3. He couldn't _____ (负担得起) an apartment himself，so he had to borrow some money from his relatives.4. As soon as I ____ (进入)the office, my colleagues served me a cup of coffee.5. The football match took nearly three hours and _____ ____ (打断) at times by rain.6. Without treatment, the patient got _____ _____ _____ (越来越弱) and finally died.7. The nurse called my name and I knew that my _____ (轮到的机会)came.二、把下列直接引语改为间接引语。

1. “Light travels faster than sound,” the teacher said to his students.________________________________________________________2.“My house is being painted now,” my cousin said to her colleague.________________________________________________________3.“My daughter will get married next week,”she said to her friend happily.________________________________________________________4. “I finished my homework yesterday,” I said to my teacher.________________________________________________________5. “You are going to meet your grandmother at this airport tomorrow,” Mother said to him.________________________________________________________6. “The sun rises from the east every day,” the mother said to his son.________________________________________________________三、从括号中选择恰当的单词补全句子。

高二英语第15单元练习题及答案.doc

UNIT 15 Destinations课时练习ⅠⅠ．单词拼写1. _______(奴隶制) is the system by which some people are owned by others.2. Fifty years ago, mixed-race marriages were f _______.3. Civil rights fighters _______ (要求) that African Americans be treated equally.4. During the Second World War, from 1937 to 1945, there were many organized _______(抵制) of Japanese goods al over China.5. People of different r joined the movement against racial d _______.6. 表明，吐露_______7. 被法律所禁止_______8. 诺贝尔和平奖_______9. 乍一看_______10.携手，联手，合伙________Ⅱ．单项选择1．You can _______us in the discussion if you ______.A．join; wish to B. join in; want to joinC．attend; don’t want to D. take part in; hope so2．I don’t really work here; I _____out until the new secretary arrives.A. just helpB. have just helpedC. am just helpingD. will just help3. ______was a time _____women had no right to vote.A. There; whenB. There; thatC. It; whenD. It; that4. I want to ______voice to what we all feel in wishing the teacher a quick recovery.A. makeB. sendC. giveD. take5. what did they ____out of the reading-room?A. forbid to be takenB. Forbid takingC. forbid being takenD. forbid take6. Johnson _____for 5 years for political reasons when he was young.A. was put in prisonB. was in the prisonC. got out of prisonD. was in prison7．Mary worked very hard and ______a good example to her classmates.A. gaveB. putC. setD. laid8. ---Hadn’t your sheep gone much farther _______you caught up with them?---No, and we found ______only two of them that were frozen to death.A. when; it wereB. until; /C. as; there wasD. before; it was9. The manager has been in _______lately that we have to put off the meeting till next Friday.A. so poor healthB. such poor healthC. such a poor healthD. so poor a health10. It was not until _____that _____to study English.A. did he come to Beijing; he had begunB. he came to Beijing; he has begunC. he came to Beijing; he beganD. did he come to Beijing; did he begin11. _______by his accent, the boy must have come from a North European country, say, Norway or Finland.A. Having judgedB. To judgeC. JudgedD. Judging12. When and where to build the new factory _______yet.A. is not decidedB. are not decidedC. has not decidedD. had not decided13. Standing on top of the tallest building, _________.A. the whole city could be easily seenB. we could see the whole cityC. the city is just below my feetD. just like traveling by plane14. He hurried to the booking office only _____ that all the tickets had been sold out.A. to tellB. to be toldC. tellingD. told15. I arrived late; I _____to come here.A. would be expectingB. have been expectedC. had been expectedD. was expectingⅢ．完形填空As I drove my blue Buick into the garage, I saw that a yellow Oldsmobile was 1 too close to my space. I had to drive back and forth to get my car into the 2 space. That left 3 enough room to open the door. Then one day I arrived home 4 , and just as I turned off the engine, the yellow Oldsmobile entered its space—too close to my car, 5 . At last I had a chance to meet the driver. My patience had 6 and I shouted at her, “Can’t you see you’re not 7 me enough space? Park farther over.”Banging（猛推）open her door into 8 , the driver shouted back: “Make me!”9 this she stepped out of the garage. Still, each time she got home first, she parked too close to my 10 . Then one day, I thought, “What can I do?” I soon found 11 . The next day she 12 a note on her windshield（挡风玻璃）:Dear Yellow Oldsmobile,I’m sorry my mistress（女主人）shouted at yours the other day. She's been sorry about it.I know it because she doesn't sing any more while 13 . It wasn’t like her to scream 14 .Fact is, she'd just got bad news and was taking it out on you two. I 15 you and your mistress will 16 her.Your neighbor,Blue BuickWhen I went to the 17 the next morning, the Oldsmobile was gone, but there was a note on my windshield:Dear Blue Buick,My Mistress feels sorry, too. She parked so 18 because she just learned to drive. We will park much farther over after this. I'm glad we can be 19 now.Your neighbor.Yellow OldsmobileAfter that, whenever Blue Buick 20 Yellow Oldsmobile on the road, their drivers waved cheerfully and smiled.1. A. driven B. parked C. stopped D. stayed2. A. complete B. close C. narrow D. fixed3. A. quite B. nearly C. seldom D. hardly4. A. hurriedly B. first C. finally D. timely5. A. as usual B. as planned C. as well D. as yet6. A. run into B. run about C. run out D. run off7. A. keeping B. saving C. offering D. leaving8. A. mine B. hers C. itself D. ours9. A. For B. With C. From D. Upon10. A. room B. area C. front D. side11. A. an instruction B. a result C. an answer D. a chance12. A. put B. wrote C. sent D. discovered13. A. working B. driving C. returning D. cooking14. A. on end B. so long C. like that D. any more15. A. hope B. know C. suppose D. suggest16. A. comfort B. help C. forgive D. please17. A. office B. flat C. place D. garage18. A. crazily B. eagerly C. noisily D. early19. A. neighbors B. friends C. drivers D. writers20. A. followed B. passed C. found D. greeted课时练习ⅡⅠ.单词拼写1. It was the beginning of more than 200 years for _________ (绝对的，无条件的) rights of all the people.2. Although we enjoy the f_________ of speech, it doesn’t mean that we are free to say whatever we want.3. The struggles starts with the ideas of the French R_________ and the American War of I___________.4. After the war, many rules were ___________ (废除).5. There are still organizations that fight against___________（偏见）6. 为…树立榜样__________________7. 把某人关进监狱__________________8. 以…开始_________________9. 使某人受到全国的注意__________________10. 从那时起__________________Ⅱ.单项选择1. Buying a train ticket ahead of time will usually _____ you a good seat.A. stretchB. protectC. guaranteeD. prevent2. If you use the credit card, it can save you the trouble of bringing with you.A. coinB. goldC. cashD. check3. I would like to travel by train because I can catch a _____ of something from the window of it.A. glimpseB. sightC. holdD. sense4. The traffic policemen are ____ the main cause of that terrible accident which happened the day before yesterday on the highway.A. looking intoB. looking forC. turning intoD. breaking into5. The mountain not far away from Qingdao, which looks very common, is well-known ____ “Laoshan Mount”.A. toB. forC. asD. with6. The travellers in the deep valley __ used their cellphones to keep in touch with others in another valley.A. every now and thenB. all at onceC. sooner or laterD. once upon a time7. You’d better make a careful , for next year so that you won’t have to worry about too much expense for your family.A. accountB. calculationC. analysisD. budget8. We’re flying at an of 44,000 feet.A. attitudeB. altitudeC. avenueD. airline9. you analyze the course of the experiment, you could find some similarities to the one you did two years ago.A. ShouldB. CouldC. WouldD. Might10．Jim said that the store had a food department and you can get very delicious food them.A. first-rateB. first-handC. first-degreeD. first-aidⅢ.阅读理解ASome people think that they have an answer to the problems of automobile(机动车) crowding and pollution in large cities. Their answer is the bicycle, or bike.In a great many cities, hundreds of people ride bicycles to work every day. In New York City, some bike riders have even formed a group called "Bike for a Better City". They claim(宣称) that if more people rode bicycles to work there would be fewer automobiles in the downtown section of the city and therefore less dirty air from car engines.For several years this group has been trying to get the city government to help bicycle riders. For example, they want the city to paint special lanes-for bicycles only- on some of the main streets, because when bicycle riders must use the same lanes as cars, there may be accidents. "Bike for a Better City" feels that if there were special lanes, more people would use bikes.But no bicycle lanes have been painted yet. Not everyone thinks it is a good idea. Taxi drivers don't like the idea-they say it will slow traffic. Some store owners on the main streets don't like the idea- they say that if there is less traffic, they will have less business. And more people live too far from downtown to travel by bike.The city government has not yet decided what to do. It wants to keep everyone happy. On weekends, Central Park-the largest open place in New York-is closed to cars, and the roads may be used by bicycles only. But "Bike for a Better City" says that this is not enough and keeps fighting to get bicycle lanes downtown. Until that happens, the safest place to bicycle may be in the park.1．One thing "Bike for a Better City" wants to do is to on the main streets.A. paint special lanesB. help bicycle ridersC. use the same lanes as carsD. make fewer accidents2．No bicycle lanes have been painted yet because .A. the main streets are not wide enoughB. the city government is too busy to do itC. most people live too far to travel by bikeD. a lot of people don't think it is a good idea3．Central Park is closed to cars and may be used by bicycles only .A. on Saturday and SundaysB. in the afternoonsC. in holidaysD. on weekdaysBIn the western part of the United States where the Plains Indians lived, a little mouse called the "bean mouse(豆鼠)"became a guide to rich stores of tasty but difficult to find food. Each season, the little animal would search out the rare (稀少的) beans hard, and store them away in its nest. The Indians learned of this and found out the hiding place. They collected most of the beans for themselves. When the mouse returned to its home and found only a few of the tasty beans left, it set to work, harder than ever, gathering more beans.This was a fine thing for the Indians, who had only to look for the nest, while the mouse had to look for the bean, but the Indian returned the favor by always making sure that the animal had enough for the winter.1．The best title for this passage is .A. Bean MouseB. A Search for BeansC. The Indians' AnimalD. The Indians and the Bean Mouse2．The "bean mouse" is important to the Plains Indians because .A. it helps them get foodB. its beans are tastyC. it is a kind of rare animalD. it has got a nest with beans3．The word "this" in the third sentence refers to .A. the bean mouseB. the bean mouse and its nestC. the fact that the bean mouse stored some kind of beans in its nestD. the fact that the bean mouse hid itself in its nest4．This story suggests that bean mouse is a kind of .A. lazy animalB. harmful animalC. clever animalD. hard working animal课时练习ⅢⅠ. 单词拼写1. The guide asked, “ what's the d_________ of your travel? ”2. It is useful to have some local c_________. You can change money at the airport.3. The word a_________ means almost the same as street or road.4. You are not allowed to pay by c_________ but in cash.5. A travel agent can help you make the necessary a_________ for your trip.6. I’ve just been informed that my lost _________ (行李) had been found.7. Tavvelling is good way to learn more about the_________（生活方式）of peoplein different countries.8. If you like shopping and going to the cinema, you should go_________.（市中心，城市商业区）9. Buying cheap tickets is one of the many ways to cut your traveling_________.（预算经费）10.“You never ask my opinion about anything,”Rod_________（抱怨）.11. 复印___________________________12. 列出___________________________13. 站在…的旁边___________________________14. 厌烦，不喜欢___________________________15. 四天的节日___________________________Ⅱ. 单项选择1．I had thought _________present would give him a surprise, but he knew the secret early.A. my beingB. me beingC. I amD. I to be2. ______the meeting himself gave them a great deal of encouragement.A. The president will attendB. The president to attendC. The president attendedD. The president’s attending3. To improve your spoken English, ______________.A. practice is neededB. it is necessary to practice itC. you need practice itD. you need a lot of practice4. _______in the countryside, though living in town, he _________his home village all the time.A. Brought up; has still thought ofB. Being brought up; is still thinking ofC. Having been brought up; still thinks ofD. Brought up; is still thinking of5. Mr. Johnson was ill. _______all day and all night caused him to be too tired.A. He workedB. His workingC. Him workingD. His to work6. He is __________poor health and needs _____in hospital.A. in; examiningB. with; to examineC. of; to be examinedD. in; examined7. If I had ________, I would visit Europe, stopping at all the small interesting places.A. a long enough vacationB. an enough vacation longC. a vacation enough longD. a long vacation enough8. I used to drink a lot of tea but these days I _________coffee.A. preferB. preferredC. have preferredD. am preferring9. ----The public store closes at 9;00 pm.----_________no need to worry; it is just 7;31 pm.A. You haveB. They haveC. It isD. There is10. I really appreciate ________to help me. But I am sure that I can manage by myself.A. your offeringB. that you offerC. you to offerD. that you are offeringⅢ.单句改错1．This phenomenon may explain to why people spend time and money on trips.2．Skiing is not the only thing which you can do in Kitzbuhel.3. Kitzbuhel is also home to one of the most challenged and exciting downhill slopesin the world.4. You can take a dip, work out at the gym or going dancing in one of the city’smany hotels and clubs.5.Try to use traveller’s cheques if possible and avoid bring too much money.Ⅳ.完形填空Mr. Williams lives in a nice house in the country with his wife. He has got a nice 1 round his house, and he often works in it on Saturdays and Sundays, because he likes flowers and enjoys working with his own 2 . Last Saturday Mr. Williams put some old 3 on after his breakfast and began 4 in his garden. After a little while he found something shining on the ground near his feet. To this 5 , it was five pence. He put it in one of his 6 and began digging again. Then he 7 another five pence on the ground and he was very happy now.He shouted to his wife, "Elizabeth, come quickly. Some's 8 a lot of money in our garden 9 I'm finding it." His wife was 10 the lunch and making a cake for tea, but she stopped and ran out 11 the garden. Then Mr. Williams found 12 more money. His wife came near and looked at it. She was very happy to and said, "A thief 13 a lot of money from one of the banks 14 here a few week ago. The police 15 him, but didn't find 16 of the money. Did the 17 bring it here and hide it in our garden?" Mr. Williams began looking for more money in the ground ,but then he 18 something cold in his trousers. It ran down off his legs like cold water. Mr. Williams put his 19 down quickly and five pence fell into it. A 20 ! He had a hole in his pocket!1. A. garden B. road C. ground D. field2. A. brains B. body C. hands D. strength3. A. tools B. clothes C. money D. flowers4. A. digging B. looking C. walking D. reading5. A. sorrow B. delight C. worry D. disappointed6. A. pockets B. bags C. boxes D. books7. A. watched B. found C. searched D. observed8. A. lost B. hidden C. left D. grown9. A. and B. but C. because D. so10. A. eating B. having C. burning D. cooking11. A. from B. of C. into D. for12. A. little B. lot C. so D. some13. A. robbed B. cheated C. made D. stole14. A. near B. from C. to D. by15. A. stopped B. scolded C. caught D. punished16. A. nothing B. none C. anything D. any17. A. prisoner B. policeman C. owner D. thief18. A. found B. felt C. saw D. knew19. A. foot B. pocket C. hand D. tool20. A. penny B. hand C. wallet D. hole课时练习ⅣⅠ.单词拼写1. I was u about the argument I'd had with my mother.2. An a is a company that provides scheduled flights to various places.3. You may also have to obtain a v , which says how long you can stay in the foreign country.4. A d skiing race is both challenging and exciting.5. Our teacher often （分析）the text in detail.6. He （保证）we would enjoy our stay in Wuxi.7. 调查，观察8. 教育，抚养9. 世界一流10. 捉弄，对……玩恶作剧11. 去游泳，去洗澡12. 不时地，时不时地13. 渴望14. 让某人看一眼15. 变冷，冷却，冷静Ⅱ. 单项选择1．Protesters(抗议者) _____ the meeting by singing and shouting．A．upset B．attended C．held D. ignored2．In the storm, we must_____every family_______loss．A．promise；by B. promise; against C．guarantee；from D. keep; for 3．Victor apologized for_____ to inform me of the change in the plan．A．his being not able B．him not to be ableC．his not being able D．him to be not able4. _______I went to Zhang Jiajie，I was shocked by its beauty．I’d say it was themost beautiful place I saw ________.A．The first time; for the first timeB．For the first time; the first timeC．The first time; at first timeD．A first time; for the second time5. The girl________forward to buying a new gold watch．A．referred to look B．refers to lookingC．referred to looks D．referring to look6．________you have any difficulty in getting tickets，ring this number．A．Should B．Shall C．Can D．Will7．He looked around and caught a man _____ his hand into the pocket of a passenger．A．put B．to be putting C．to put D．putting8．The pilot asked all the passengers on board to remain ________ as the plane was making a landing．A．seat B．seating C．seated D．to be seating9. He wondered if he could slip out of the lecture hall without anyone_______ .A．noticing B．noticed C．to notice D．being noticed 10．Don’t use words, expresions, or phrases_____ only to people with specific knowledge.A. being knownB. knownC. to be knownD. having been known Ⅲ．单句改错1．Although the unboiling water looks clean, I prefer not to drink it．2．Heard the music, he began to miss his hometown．3．To climb the mountain road is hard work and going down hills is great fun．4．We should get the bike repair.5．His parents died，left him an orphan.Ⅳ．阅读理解AA letter to Edward, a columnist (报刊专栏作家)Dear Mr. Expert,I grew up in an unhappy and abusive home. I always promised myself that I’d get out as soon as possible. Now, at the age of 20, I have a good job and a nice house, and I’m really proud of the independence I’ve achieved.Here’s the problem: several of my friends who still live with their parents wish they had places like mine—so much so that they make mine theirs.It started out with a couple of them spending the weekends with me. But now they seem to take it for granted that they can show up any time they like. They bring boyfriends over, talk on the phone and stay out forever.I enjoy having my friends here sometimes—it makes the place feel comfortable and warm—but this is my home, not a party house. I was old enough to move out on my own, so why can’t I seem to ask my friends to respect my privacy(隐私)?Joan Edward’s reply to JoanDear Joan，If your family didn’t pay attention to your needs when you were a child, you probably have trouble letting others know your needs now.And if you’ve gathered your friends around you to rebuild a happy family atmosphere(气氛),you may fear that saying no will bring back the kind of conflict you grew up with—or destroy the nice atmosphere you now enjoy. You need to understand that in true friendship it’s Okay to put your own needs first from time to time.Be clear about the message you want to send. For example,“I really love your company but I also need some privacy. So please call before you come over.”Edward1.We can learn from the first letter that Joan .A. lives away from her parentsB. takes pride in her friendsC. knows Edward quite wellD. hates her parents very much2. We can infer from the first letter that .A. Joan considers her friends more important than her privacyB. Joan’s friends visit her more often than she can acceptC. Joan doesn’t like the parties at allD. Joan dislikes the boyfriends her friends bring over3. According to Edward, why can’t Joan tell her friends her feelings?A. She is afraid of hurting her friends.B. She does not understand true friendship.C. Her family experience stops her from doing so.D. She does not put her needs first.4.The underlined word “conflict” in the second letter means .A. dependent lifeB. fierce fightC. bad mannersD. painful feeling5. The second letter suggests that Edward .A. is worried about Joan’s problemB. warns Joan not to quarrel with her friendsC. advises Joan on how to refuse peopleD. encourages Joan to be brave enoughB“The pen is more powerful than the sword.” There have been many writers who used their pens to fight things that were wrong. Mrs. Harriet Beecher Stowe was one of them.She was born in the U.S.A. in 1811.One of her books not only made her famous but has been described as one that excited the world, and was helpful in causing a civil war and freeing the enslaved race. The civil war was the American Civil War of 1861,in which the Northern States fought the Southern States and finally won.This book that shook the world was called "Uncle Tom's Cabin". There was time when every English-speaking man, woman, and child has read this novel that did so much to stop slavery. Not many people read it today, but it is still very interesting. The book has shown us how a warm-hearted writer can arouse(唤起)people's sympathies(同情).The author herself had neither been to the Southern States nor been a slave. The Southern Americans were very angry at the book, which they said did not at all represent(描述)true state of affairs, but the Northern Americans were wildly excited over it and were so inspired by it that they were ready to go to war to set the slavesfree.1. According to the passage____.A. every English-speaking person has read "Uncle Tom's Cabin"B. "Uncle Tom's Cabin" was not very interestingC. those who don't speak English cannot have read "Uncle Tom's Cabin"D. the book "Uncle Tom's Cabin" did a great deal in the American Civil War2. How old was Mrs. Harriet Beecher Stowe when her world famous book was publishedA. About sixty years old.B. Over fifty years old.C. In her forties.D. Around twenty years old.3. What do you learn about Mrs. Harriet Beecher Stowe from the passageA. She had been living in the north of America before the American Civil War broke out.B. She herself encouraged the northern Americans to go to war to set the slaves free.C. She was better as writing as swinging(挥舞)a sword.D. She had once been a slave.4. Why could Mrs. Harriet Beecher Stowe's book cause a civil war in AmericaA. She wrote so well that Americans loved her very much.B. She disclosed the terrible wrongs that had been done to the slaves in the Southern States.C. The southern Americans hated the book while the northern Americans like it.D. The book had been read by many Americans.5. What can we learn from the passageA. We needn't use weapons(武器)to fight things that are wrong.B. A writer is more helpful in a war than a soldier.C. We must understand the importance of literature(文学) and art.D. No war can be won without such a book as 〝Uncle Tom's Cabin".课时练习ⅤⅠ.阅读理解May: Happenings from the PastMay 5, 1884Issac Murphy, son of a slave and perhaps the greatest horse rider in American history, rides Buchanan to win his first Kentucky Derby. He becomes the first rider ever to win the race three times.May 9, 1754Benjamin Franklin's Pennsylvania gazette produces perhaps the first American political cartoon (漫画), showing a snake cut in pieces with the words "Join or Die" printed under the picture.May 11, 1934The first great dust storm of the Great Plains Dust Bowl, the result of years of drought (干旱), blows topsoil all the way to New York City and Washington, D.C.May 19, 1994Jacqueline Lee Bouvier Kennedy Onassis, former first lady and one of the most famous people ofthe 1960s died of cancer in New York City at the age of 64.May 24, 1844Samuel F.B Morse taps out the first message, "What hath God wrought," over the experimental long-distance telegraph line which runs from Washington, D.C., to Baltimore, Md.1. We know from the text that Buchanan is _______.A. Isaac's fatherB. a winning horseC. a slave taking care of horsesD. the first racing horse in Kentucky2. What is the title of the first American political cartoon ?A. Join or DieB. Pennsylvania GazetteC. What Hath God WroughtD. Kentucky Derby3. In which year did the former first lady Jacqueline die ?A. 1934B. 1960C. 1964D. 19944. Which of the following places has to do with the first telegram in history ?A. Washington, D.C.B. New York CityC. KentuckyD. PennsylvaniaⅡ. 短文改错When our six children were young，suppertime is always 1. _______being interrupted by neighborhood children ring the bell. 2. _______They wanted one child or another to come out and played. 3. _______Finally we had good idea. We hung a sign on the front 4. _______door that was read：“We’re having dinner. Come back 5. _______later.”That night，we sat down to what they thought would 6. _______be a pleasant, uninterrupted meals. But as soon as we 7. _______began dinner, the doorbell rang. On the front door stood a 8. _______five-year-old boy from across the street. He looked up 9. _______at us and said，“I just want to know what the sign say.”10. _______Ⅲ. 书面表达写一篇记叙文，题目是At the Seaside。

英汉口译知到章节答案智慧树2023年四川大学

英汉口译知到章节测试答案智慧树2023年最新四川大学第一章测试1.The correct Chinese interpretation of “metaverse” is （）.参考答案:元宇宙2.Just like Gaudi’s （）, the Sagrada Familia, the metaverse may take a whileto complete.参考答案:cathedral3.The company Meta was formerly known as（）.参考答案:Facebook4.The correct Chinese interpretation of “scam” is （）.参考答案:诈骗;骗局5.The correct Chinese interpretation of “gimmicks” is “噱头”. （）参考答案:对第二章测试1.The correct English interpretation of “新冠肺炎疫情” is （）.参考答案:the COVID-19 pandemic2.Th e correct English interpretation of “促进全球平衡、协调、包容发展”is “topromote balanced, coordinated and inclusive global development”.（）参考答案:对3.The correct English interpretation of “遇山一起爬，遇沟一起跨”is （）参考答案:“Climb the hill together and go down the ravine together.”4.“The opening to traffic of the China-Laos railway have effectively boostedinstitutional and physical connectivity in our region” is correct Englishinterpretation of “中老铁路建成通车，有效提升了地区硬联通、软联通水平”。

第15章功和机械能单元测试

十五章单元测试题一、单项选择题（每题3分，共42分）（）1．(2010福建龙岩，14题)林雨同学将掉落在地面的物理课本捡起来放在课桌上，他对课本所做的功最接近于A.0.02JB.0.2JC.2JD.20J （）2．（2010年广东茂名，4题）关于做功和功率的说法中正确的是 A ．有力作用在物体上，力—定对物体做功B ．在光滑水平面上做匀速直线运动的物体，没有力做功C ．物体受到的作用力越大，力对物体做功就越多D ．力对物体做功越多，功率就越大（）3.（2010四川自贡，33题）甲升降机比乙升降机的机械效率高，它们分别把质量相同的物体匀速升高相同的高度，两者相比，甲升降机A ．做的总功较少B ．做的总功较多C ．提升重物做的有用功较少D ．提升重物做的有用功较多（）4.（2010四川广安，11题）李玲玲同学用水桶从水井中提水做清洁，她在把水从井底提上来的过程中，下列关于做功的说法中正确的是A ．对桶所做的功是有用功B ．对水所做的功是额外功C ．对水所做的功是有用功D ．对水所做的功是总功（）5.拖拉机在拉犁耕地时，往往行驶速度很慢，这是为了( )A ．增大牵引力B ．提高机械效率C ．提高耕地质量D ．保养好拖拉机（）6.（2010·河北省，21题）小明用两个相同的滑轮组成不同的滑轮组（如图7所示），分别将同一物体匀速提高到相同高度，滑轮组的机械效率分别为η1、η2。

下列关系正确的是（忽略绳重及摩擦）A ．F 1 > F 2，η 1 = η 2B ．F 1 > F 2，η 1 > η2C ．F 1 < F 2，η 1 = η 2D ．F 1 < F 2，η 1 > η 2全品中考网（）7.两个完全相同滑轮，其重力均为10牛。

分别用如图3所示的两种方式，将重40牛的物体匀速提升0．5米。

则下列判断正确的是(不计绳与滑轮的摩擦)( ) A 力F 1和F 2大小相等 B 两机械做的有用功相等 C 两绳子自由端移动距离相等 D 吧两装置的机械效率相等（）8. (2010河南省，14题)如图7所示，用F =50N 的水平拉力，通过一个动滑轮，使重为200N 的物体A 水平向右匀速移动了3mA ．拉力F 做了150J 的功 B ．拉力F 做了300J 的功C ．重力做了600J 的功D ．重力做了的功（）9.（２０１０年浙江宁波，19题）学习了功率的知识后，小科和几位同学准备做“比一比谁的功率大”的活动。

金融英语第十五章答案

金融英语第十五章答案C C h h a a p p t t e e r r1155E E x x e e r r c c i i s s e e s sI. Answer the following questions in English.1.What is swaps?A swap is an agreement between two parties to exchange sequences of cash flows for a set period of time2.Where can swaps be changed?swaps occur on the OTC market3.Who would use a swap?The motivations for using swap contracts fall into two basic categories:commercial needs and comparative advantage. The normal business operations of some firms lead to certain types of interest rate or currency exposures that swaps can alleviate. For example, consider a bank, which pays a floating rate of interest on deposits (i. e., liabilities) and earns a fixed rate of interest on loans (i. e.,assets ). This mismatch between assets and liabilities can cause trem- endous difficulties.Some companies have a comparative advantage in acquiring certain types of financing. However, this comparative advantage may not be for the type of financing desired. In this case, the company may acquire the financing for which it has a comparative advantage, then use a swap to convert it to the desired type of financing.4.what is an interest swaps?In This swap, Party A agrees to pay Party B a predetermined, fixed rate of interest on a notional principal4 on specific dates for a specified period of time. Concurrently,Party B agrees to make payments based on a floating interestrate to Party A on that same notional principal on the same specified dates for the same specified time period5.What does comparative advantage mean?During the life of the swap, the same valuation technique is used, but since,over time, the forward rates change, the PV of the variable-rate part of the swap will deviate from the unchangeable fixed-rate side of the swap. Therefore, the swap will be an asset to one party and a liability to the other. The way these changes in value are reported is the subject of IAS 39 for jurisdictions following IFRS, and FAS 133 for U.S. GAAP. Swaps are marked to market by debt security traders to visualize their inventory at a certain time.6.What is a swaption?An interest rate swap is a derivative in which one party exchanges a stream of interest payments for another party's stream of cash flows. Interest rate swaps can be used by hedgers to manage their fixed or floating assets and liabilities. They can also be used by speculators to replicate unfunded bond exposures to profit from changes in interest rates. Interest rate swaps are very popular and highly liquid instruments. Interest rate swaps are simply the exchange of one set of cash flows (based on interest rate specifications) for another. Because they trade OTC3, they are really just contracts set up between two or more parties, and thus can be customized in any number of ways.7.What is plain vanilla interest rate swap?the plain vanilla interest rate swap: it is the simplest swap structure, in which one party receives a fixed interest rate agreed in advance and the other party a variable reference interest rate.8.How to Exit a Swap Agreement?Interest rate risk originates from changes in thefloating rate. In a plain vanilla fixed-for-floating swap, the party who pays the floating rate benefits when rates fall. (Note that the party that pays floating has aninterest rate exposure analogous to a long bond position. ) . Credit risk on the swap comes into play if the swap is in the money or not. If one of the parties is in the money, then that party faces credit risk of possible default by another party. This is not true with ETSE MTIRS Index~II.Fill in the each blank with an appropriate word orexpression.1.Swaps are not exchange-traded instruments. Instead swapsare --customized---contracts that are traded in theover-the-counter(OTC)marketbetween---private---parties.2.In a plain vanilla swap, the two cash flows are paid in thesame currency. The specified payment dates are calledsettle- ment---dates----, and the time between is calledsettlement--periods--.3. The normal business __ operations __ of some firms leadto certain types of interest rate or currency exposures that swaps can--alleviate-4. An interest rate swap is a ---derivative--- in which oneparty exchanges a stream of interest payments for another party's stream of cash flows. Interest rate swaps can be used by --hedgers-- to manage their fixed or floating assetsand liabilities.5. Today, interest rate swaps are often u.sed by firms to---alter--their exposure to interest-rate fluctuations,by ---- swapping fixed-rate obligations forfloating rate obligations, or vice versa.6. Interest rate swaps expose users to --interest--- riskand ---- credit risk.III. Translate the followin~ sentences into English.1．互换是借款人和投资者用来控制风险的衍生金融工具。

曼昆经济学原理英文版文案加习题答案15章

曼昆经济学原理英⽂版⽂案加习题答案15章stic CompetitionWHAT’S NEW IN THE S EVENTH EDITION:There are no major changes to this chapter.LEARNING OBJECTIVES:By the end of this chapter, students should understand:what market structures lie between monopoly and competition.competition among firms that sell differentiated products.how the outcomes under monopolistic competition and under perfect competition compare.the desirability of outcomes in monopolistically competitive markets.the debate over the effects of advertising.the debate over the role of brand names.CONTEXT AND PURPOSE:Chapter 16 is the fourth chapter in a five-chapter sequence dealing with firm behavior and the organization of industry. The previous two chapters developed the two extreme forms of market structure —competition and monopoly. The market structure that lies betweenMONOPOLISTIC COMPETITION16competition and monopoly is known as imperfect competition. There are two types of imperfect competition—monopolistic competition and oligopoly. This chapter addresses monopolistic competition while the final chapter in the sequence addresses oligopoly. The analysis in this chapter is again based on the cost curves developed in Chapter 13.The purpose of Chapter 16 is to address monopolistic competition—a market structure in which many firms sell products that are similar but not identical. Monopolistic competition differs from perfect competition because each of the many sellers offers a somewhat different product. As a result, monopolistically competitive firms face a downward-sloping demand curve while competitive firms face a horizontal demand curve at the market price. Monopolistic competition is extremely common.KEY POINTS:A monopolistically competitive market is characterized by three attributes: many firms,differentiated products, and free entry.The long-run equilibrium in a monopolistically competitive market differs from that in a perfectly competitive market in two related ways. First, each firm in a monopolistically competitive market has excess capacity. That is, it chooses a quantity that puts it on the downward-sloping portion of the average-total-cost curve. Second, each firm charges a price above marginal cost.Monopolistic competition does not have all of the desirable properties of perfectcompetition. There is the standard deadweight loss of monopoly caused by the markup of price over marginal cost. In addition, the number of firms (and thus the variety ofproducts) can be too large or too small. In practice, the ability of policymakers tocorrect these inefficiencies is limited.The product differentiation inherent in monopolistic competition leads to the use ofadvertising and brand names. Critics of advertising and brand names argue that firms usethem to manipulate consumers’ tast es and to reduce competition. Defenders of advertising and brand names argue that firms use them to inform consumers and to compete morevigorously on price and product quality.CHAPTER OUTLINE:I. Between Monopoly and Perfect CompetitionA. The typical firm has some market power, but its market power is not as great as thatdescribed by monopoly.B. Firms in imperfect competition lie somewhere between the competitive model and themonopoly model.C. Definition of oligopoly: a market structure in which only a few sellers offer similaror identical products.1. Economists measure a market’s domination by a small number of firms with astatistic called a concentration ratio.2. The concentration ratio is the percentage of total output in the market suppliedby the four largest firms.3. In the . economy, most industries have a four-firm concentration ratio under 50%.D. Definition of monopolistic competition: a market structure in which many firms sellproducts that are similar but not identical.1. Characteristics of Monopolistic Competitiona. Many Sellersb. Product Differentiationc. Free EntryE. Figure 1 summarizes the four types of market structure. Note that it is the number offirms and the type of product sold that distinguishes one market structure fromanother.II. Competition with Differentiated ProductsA. The Monopolistically Competitive Firm in the Short Run1. Each firm in monopolistic competition faces a downward-sloping demand curvebecause its product is different from those offered by other firms.2. The monopolistically competitive firm follows a monopolist's rule for maximizingprofit.a. It chooses the output level where marginal revenue is equal to marginal cost.b. It sets the price using the demand curve to ensure that consumers will demand exactly the amount produced.Figure 23. We can determine whether or not the monopolistically competitive firm is earning a profit or loss by comparing price and average total cost.a. If P > ATC, the firm is earning a profit.b. If P < ATC, the firm is earning a loss.c. If P = ATC, the firm is earning zero economic profit.B. The Long-Run Equilibrium1. When firms in monopolistic competition are making profit, new firms have an incentive to enter the market.a. This increases the number of products from which consumers can choose.b. Thus, the demand curve faced by each firm shifts to the left.c. As the demand falls, these firms experience declining profit.2. When firms in monopolistic competition are incurring losses, firms in the market will have an incentive to exit.a. Consumers will have fewer products from which to choose.b. Thus, the demand curve for each firm shifts to the right.c. The losses of the remaining firms will fall.3. The process of exit and entry continues until the firms in the market are earning zero profit.a. This means that the demand curve and the average-total-cost curve are tangentto each other.b. At this point, price is equal to average total cost and the firm is earningzero economic profit.Figure 3Remember that students have a hard time understanding why a firm willcontinue to operate if it is earning “only” zero economic profit. Remind4. There are two characteristics that describe the long-run equilibrium in a monopolistically competitive market.a. Price exceeds marginal cost (due to the fact that each firm faces a downward-sloping demand curve).b. Price equals average total cost (due to the freedom of entry and exit).C. Monopolistic versus Perfect Competition1. Excess Capacitya. The quantity of output produced by a monopolistically competitive firm is smaller than the quantity that minimizes average total cost (the efficient scale).b. This implies that firms in monopolistic competition have excess capacity, because the firm could increase its output and lower its average total cost of production.c. Because firms in perfect competition produce where price is equal to the minimum average total cost, firms in perfect competition produce at theirefficient scale.2. Markup over Marginal Costa. In monopolistic competition, price is greater than marginal cost because the firm has some market power.b. In perfect competition, price is equal to marginal cost.D. Monopolistic Competition and the Welfare of Society1. One source of inefficiency is the markup over marginal cost. This implies a deadweight loss (similar to that caused by monopolies).2. Because there are so many firms in this type of market structure, regulating these firms would be difficult.3. Also, forcing these firms to set price equal to marginal cost would force them out of business (because they are already earning zero economic profit).4. There are also externalities associated with entry.a. The product-variety externality occurs because as new firms enter, consumers get some consumer surplus from the introduction of a new product. Note thatthis is a positive externality.b. The business-stealing externality occurs because as new firms enter, other firms lose customers and profit. Note that this is a negative externality.c. Depending on which externality is larger, a monopolistically competitive market could have too few or too many products.5. In the News: Insufficient Variety as a Market Failurea. Firms may insufficiently service consumers with unusual preferences in marketswith large fixed costsb. This article from Slate describes how some consumers get left out of the market because of the high fixed costs associated with creating additional varietiesof a product.III. AdvertisingA. The Debate over Advertising1. The Critique of Advertisinga. Firms advertise to manipulate people's tastes.b. Advertising impedes competition because it increases the perception of product differentiation and fosters brand loyalty. This means that consumers will beless concerned with price differences among similar goods.2. The Defense of Advertisinga. Firms use advertising to provide information to consumers.b. Advertising fosters competition because it allows consumers to be betterinformed about all of the firms in the market.3. Case Study: Advertising and the Price of Eyeglassesa. In the United States during the 1960s, states differed on whether or not theyallowed advertising for optometrists.b. In the states that prohibited advertising, the average price paid for a pair ofeyeglasses in 1963 was $33; in states that allowed advertising, the averageprice was $26 (a difference of more than 20%).B. Advertising as a Signal of Quality1. The willingness of a firm to spend a large amount of money on advertising may be a signal to consumers about the quality of the product being offered.2. Example: Kellogg and Post have each developed a new cereal that would sell for $3per box. (Assume that the marginal cost of producing the cereal is zero.) Eachcompany knows that if it spends $10 million on advertising, it will get onemillion new consumers to try the product. If consumers like the product, they will buy it again.a. Post has discovered through market research that its new cereal is not verygood. After buying it once, consumers would not likely buy it again. Thus, itwill only earn $3 million in revenue, which would not be enough to pay for the advertising. Therefore, it does not advertise.b. Kellogg knows that its cereal is great. Each person that buys it will likelybuy one box per month for the next year. Therefore, its sales would be $36million, which is more than enough to justify the advertisement.c. By its willingness to spend money on advertising, Kellogg signals to consumersthe quality of its cereal.3. Note that the content of the advertisement is unimportant; what is important isthat consumers know that the advertisements are expensive.C. Brand Names1. In many markets there are two types of firms; some firms sell products with widelyrecognized brand names while others sell generic substitutes.2. Critics of brand names argue that they cause consumers to perceive differencesthat do not really exist.3. Economists have defended brand names as a useful way to ensure that goods are ofhigh quality.a. Brand names provide consumers with information about quality when qualitycannot be judged easily in advance of purchase.b. Brand names give firms an incentive to maintain high quality, because firmshave a financial stake in maintaining the reputation of their brand names.SOLUTIONS TO TEXT PROBLEMS:Quick Quizzes1. Oligopoly is a market structure in which only a few sellers offer similar oridentical products. Examples include the market for breakfast cereals and the world market for crude oil. Monopolistic competition is a market structure in which many firms sell products that are similar but not identical. Examplesinclude the markets for novels, movies, restaurant meals, and computer games.2. The three key attributes of monopolistic competition are: (1) there are manysellers; (2) each firm produces a slightly different product; and (3) firms can enter or exit the market freely.Figure 1 shows the long-run equilibrium in a monopolistically competitive market.This equilibrium differs from that in a perfectly competitive market because price exceeds marginal cost and the firm does not produce at the minimum point ofaverage total cost but instead produces at less than the efficient scale.Figure 13. Advertising may make m arkets less competitive if it manipulates people’s tastesrather than being informative. Advertising may give consumers the perception that there is a greater difference between two products than really exists. That makes the demand curve for a product more inelastic, so the firms can then chargegreater markups over marginal cost. However, some advertising could make markets more competitive because it sometimes provides useful information to consumers,allowing them to take advantage of price differences more easily. Advertising alsofacilitates entry because it can be used to inform consumers about a new product.In addition, expensive advertising can be a signal of quality.Brand names may be beneficial because they provide information to consumers aboutthe quality of goods. They also give firms an incentive to maintain high quality,since their reputations are important. But brand names may be criticized becausethey may simply differentiate products that are not really different, as in thecase of drugs that are identical with the brand-name drug selling at a much higherprice than the generic drug.Questions for Review1. The three attributes of monopolistic competition are: (1) there are many sellers;(2) each seller produces a slightly different product; and (3) firms can enter orexit the market without restriction. Monopolistic competition is like monopolybecause firms face a downward-sloping demand curve, so price exceeds marginal cost.Monopolistic competition is like perfect competition because, in the long run,price equals average total cost, as free entry and exit drive economic profit tozero.2. In Figure 2, a firm has demand curve D1 and marginal-revenue curve MR1. The firm ismaking profits because at quantity Q1, price (P1) is above average total cost (ATC).Those profits induce other firms to enter the industry, causing the demand curveto shift to D2 and the marginal-revenue curve to shift to MR2. The result is adecline in quantity to Q2, at which point the price (P2) equals average total cost(ATC), so profits are now zero.Figure 23. Figure 3 shows the long-run equilibrium in a monopolistically competitive market.Price equals average total cost. Price is above marginal cost.Figure 34. Because, in equilibrium, price is above marginal cost, a monopolistic competitorproduces too little output. But this is a hard problem to solve because: (1) the administrative burden of regulating the large number of monopolisticallycompetitive firms would be high; and (2) the firms are earning zero economicprofits, so forcing them to price at marginal cost means that firms would lose money unless the government subsidized them.5. Advertising might reduce economic well-being because it manipulates people'stastes and impedes competition by making products appear more different than theyreally are. But advertising might increase economic well-being by providing usefulinformation to consumers and fostering competition.6. Advertising with no apparent informational content might convey information to consumers if it provides a signal of quality. A firm will not be willing to spendmuch money advertising a low-quality good, but may be willing to spend significantly more to advertise a high-quality good.7. The two benefits that might arise from the existence of brand names are: (1) brand names provide consumers information about quality when quality cannot be easily judged in advance; and (2) brand names give firms an incentive to maintain high quality to maintain the reputation of their brand names.Quick Check Multiple Choice1. b2. d3. a4. d5. a6. cProblems and Applications1. a. Tap water is a monopoly because there is a single seller of tap water to a household .b. Bottled water is a monopolistically competitive market. There are many sellersof bottled water, but each firm tries to differentiate its own brand from therest.c. The cola market is an oligopoly. There are only a few firms that control alarge portion of the market.d. The beer market is an oligopoly. There are only a few firms that control alarge portion of the market.2. a. The market for wooden #2 pencils is perfectly competitive because pencils by any manufacturer are identical and there are a large number of manufacturers.b. The market for copper is perfectly competitive, because all copper is identical and there are a large number of producers.c. The market for local electricity service is monopolistic because it is anatural monopoly—it is cheaper for one firm to supply all the output.d. The market for peanut butter is monopolistically competitive because different brand names exist with different quality characteristics.e. The market for lipstick is monopolistically competitive because lipstick fromdifferent firms differs slightly, but there are a large number of firms thatcan enter or exit without restriction.3. a. A firm in monopolistic competition sells a differentiated product from itscompetitors.b. A firm in monopolistic competition has marginal revenue less than price.c. Neither a firm in monopolistic competition nor in perfect competition earnseconomic profit in the long run.d. A firm in perfect competition produces at the minimum average total cost in thelong run.e. Both a firm in monopolistic competition and a firm in perfect competitionequate marginal revenue and marginal cost.f. A firm in monopolistic competition charges a price above marginal cost.4. a. Both a firm in monopolistic competition and a monopoly firm face a downward-sloping demand curve.b. Both a firm in monopolistic competition and a monopoly firm have marginalrevenue that is less than price.c. A firm in monopolistic competition faces the entry of new firms selling similarproducts.d. A monopoly firm earns economic profit in the long run.e. Both a firm in monopolistic competition and a monopoly firm equate marginalrevenue and marginal cost.f. Neither a firm in monopolistic competition nor a monopoly firm produces thesocially efficient quantity of output.5. a. The firm is not maximizing profit. For a firm in monopolistic competition,price is greater than marginal revenue. If price is below marginal cost,marginal revenue must be less than marginal cost. Thus, the firm should reduce its output to increase its profit.b. The firm may be maximizing profit if marginal revenue is equal to marginal cost.However, the firm is not in long-run equilibrium because price is less thanaverage total cost. In this case, firms will exit the industry and the demandfacing the remaining firms will rise until economic profit is zero.c. The firm is not maximizing profit. For a firm in monopolistic competition,price is greater than marginal revenue. If price is equal to marginal cost,marginal revenue must be less than marginal cost. Thus, the firm should reduce its output to increase its profit.。

算法大全第15章_常微分方程的解法

-1-第十五章常微分方程的解法建立微分方程只是解决问题的第一步，通常需要求出方程的解来说明实际现象，并加以检验。

如果能得到解析形式的解固然是便于分析和应用的，但是我们知道，只有线性常系数微分方程，并且自由项是某些特殊类型的函数时，才可以肯定得到这样的解，而绝大多数变系数方程、非线性方程都是所谓“解不出来”的，即使看起来非常简单的方程如22dyy x dx=+，于是对于用微分方程解决实际问题来说，数值解法就是一个十分重要的手段。

§1 常微分方程的离散化下面主要讨论一阶常微分方程的初值问题，其一般形式是(,)()dyf x y a x bdxy a y ⎧=≤≤⎪⎨⎪=⎩ (1) 在下面的讨论中，我们总假定函数(,)f x y 连续，且关于y 满足李普希兹(Lipschitz)条件，即存在常数L ，使得|(,)(,)|||f x y f x y L y y -≤-这样，由常微分方程理论知，初值问题(1)的解必定存在唯一。

所谓数值解法，就是求问题（1）的解 y (x )在若干点012N a x x x x b =<<<<=处的近似值(1,2,,)n y n N =的方法，(1,2,,)n y n N = 称为问题（1）的数值解，1n n n h x x +-=称为由n x 到1n x +的步长。

今后如无特别说明，我们总取步长为常量h 。

建立数值解法，首先要将微分方程离散化，一般采用以下几种方法：（i ）用差商近似导数若用向前差商()()1n n y x y x h+-代替()n y x '代入（1）中的微分方程，则得()()()()1,(0,1,)n n n n y x y x f x y x n h+-≈=化简得()()()()1,n n n n y x y x hf x y x +≈+如果用()n y x 的近似值n y 代入上式右端，所得结果作为()1n y x +的近似值，记为1n y +，则有()1,(0,1,)n n n n y y hf x y n +=+=(2)这样，问题（1）的近似解可通过求解下述问题()10,(0,1,)()n n n n y y hf x y n y y a +⎧=+=⎨=⎩ (3) 得到，按式（3）由初值0y 可逐次算出1y ,2y ,…。

高级英语Lesson 15 No Signposts in the Sea 课后练习及答案教程文件

高级英语L e s s o n15 N o S i g n p o s t s i n t h e S e a课后练习及答案EXERCISES 15Ⅰ. Give brief answers to the following questions, using your own words as much as possible:1) What pleasure does Edmund Carr get by observing Laura without her knowing it? What compliment does he pay her?2) Does Carr appreciate natural beauty? Was he always like that?3) What effect does the moon and the cool water of the swimming pool have on him?4) What kind of coastline does he like? Why?5) Who is in charge of the lighthouse? Does he like his job?6) Why does Edmund Carr like islands?7) Why does he say: "God, is there no escape from suffering and sin? "8) What is the 'green flash'?Ⅱ. Paraphrase:1) The Colonel, who is not too offensively an Empire builder, sometimes tries to talk to me about public affairs2) Or maybe Laura's unwitting influence has called it out.3) Dismissive as a Pharisee, I regarded as moonlings all those whose life was lived on a less practical plane.4) And now see how I stand, as sentimental and sensitive as any old maid doing water-colours of sunsets!5) I want my fill of beauty before I go.6) Thus, I imagine, must the pious feel cleansed on leavingthe confessional after the solemnity of absolution.7) there is a touch of rough poetry about him8) I like also the out-of-the-way information which he imparts from time to time without insistence9) I suspect also that there is quite a lot of lore stored away in the Colonel's otherwise not very interesting mind.10) This is the new Edmund Carr with a vengeance.Ⅲ.Translate the following into Chinese:1) What I like best are the stern cliffs, with ranges of mountains soaring behind them, full of possibilities, peaks to be scaled only by the most daring. What plants of the high alti tudes grow unravished among their crags and valleys? So do I let my imagination play over the recesses of Laura's character, so austere in the foreground but nurturing what treasures of tenderness, like delicate flowers, for the discovery of the venturesome.2) In all this serenity of ocean it is seldom that we espy so much as another ship; the jolly dolphins and the scratchy little flying-fish have the vast circle all to themselves, 'the Flying Fish, who has a part with the birds, ' and doubtless are glad to see the last of the monster which bears us into and out of sight. Our wake closes up and we might never have been. But it does happen from time to time that an island appears on the horizon, nameless to us and full of mystery, the peak of a submarine mountain range , lonely, unblemished, re mote. Does one like islands because one unconsciously appropriates them, a small manageable domain in a large unmanageable world? I cannot tell why it should give me suck a queer sensation to reflect that that island has always been there (unless indeed it be no more than the work of the patient coral) and will be there still, should I return to find it waiting for me.IV. Look up the dictionary for the following loan words. Try to find out from what languages they are borrowed and then put theminto Chinese.Model: creme de menthe-- (法) 薄荷酒1) ad hoe 2) blitzkrieg3) skoal 4) charg6 d'affairs5) concerto 6) coup d'dtat7) d6eor 8) detente9) hors d oeurves 10) intermezzo11) kimono 12) kowtow13) kulak 14) macho15) smorgasbord 16) status quo17) fiesta 18) rajah19) emir 20)eurekaⅤ.Make sentences with the following words using the parts of speech indicated in the brackets:1) fill (v. n. ) 6) range (n. v. )2) ripple (n. v. ) 7) beach (n. v. )3) marble (n. v. ) 8) catch (v. n. )4 ) pile (n. v. ) 9) hump (n. v. )5) touch (v. n. ) 10) obscure (adj. v. )Ⅵ.pick out from the text all th e words and phrases describing colours.Ⅶ.Replace the italicized words with simple, everyday words or expressions"1) and thus beguile ourselves for an hour or so after dinner ( )2) prefacing his remarks by 'Of course it's not for me to suggest to you' ( )3) I regarded as moonlings all those whose life was lived on a less practical plane. ( )4) I once flattered myself that I was an adult man. ( )5) or a low-lying arid stretch with miles of white sandy beach ( )6) So do I let my imagination play over the recesses of Laura’s character, so austere in the foreground ( )7) Darkness falls, and there is nothing but the intermittent gleam of a lighthouse on a solitary promontory. ( )8) which he imparts from time to time without insistence ( )9) and it is not a sensation I could expect anyone save Laura to understand ( )10) We gazed, as the ship slid by and the humps receded into darkness and even the lights were obscured by the shoulder of a hill ( ) ( )11) ‘ Vicious viridian’ I say, not to be outdone. ( )12) I would never have believed in the simplde bliss of being, day after day, at sea. ( )Ⅷ. Replace the italicized words or phrases with specific words that appear in the text:1) The teacher tends to fill us with too many facts. ( )2) As the policemen approached on horseback, the demonstratorswent away quickly in different directions. ( )3) The thief moved stealthily along the corridor. ( )4) The detective inspected the room and wrote somethinghastily in his notebook. ( )5) Prices went up rapidly when the war broke out. ( )6) There is more and more work for me. ( )7.)Some idlers were standing about in a lazy way at the street corner. ( )8) After the tide went back, the kids began to pick shells on the shore. ( )9) On hearing the shot, he quickly put out his hand and took the gun lying on the table. ( )10) She struck him on the face with the palm of her hand. ( )Ⅸ.Point out the metaphors, similes and alliterations used in the text.Ⅹ.Point out the f igures of speech used in the following sentences:1) in the evening she wears soft rich colours ( )2) he says he used to read me ( )3) I want my fill of beauty before I go. ( )4) The young moon lies on her back tonight as is her habit in the tropics, and as, I think, is suitable if not seemly for a virgin. ( )5) and the cool support of the water ( )6) I wondered what mortal controlled it, in what must be oneof the loneliest, most forbidding spots on earth. ( )7) and the sky a tender palette of pink and blue ( )8) I had no temptation to take a flying holiday to the South ( )9) And then I like all the small noises of a ship: the faint creaking, as of the saddle-leather to a horseman riding across turf, the slap of a rope, the hiss of sudden spray. ( )10) but above all I love these long purposeless days in whichI shed all that I have ever been. ( )Ⅺ. Choose the right word from the list given below for each blank. Pay attention to the correct combinations of adverbs and adjectives.disappointed simple beautifulconscious close highobvious inadequate beatenignorant impartial confidentinterested clear jealousexaggerated1) A referee should always try to be strictly __2) The answer is laughably __ when you think it over.3) The rate of income-tax in this country is astronomically4) He was insanely __ of his brother's success. 5) Thechildren played on, blissfully __ of their parents' death. 6) Our host made it painfully __ that we should leave.7) The casualties in the war have been grossly __8) The team played badly and were soundly __9) It was abundantly __ to everyone that he had something on his mind.10) Just before the exam, he appeared to be supremely __ of Success.11) He was bitterly __ when he heard the result.12)The roads are woefully __ and simply can’t meet today’s requirements?13)The bullet passed uncomfortably __ to his head.14)Jim is keenly__ in collecting stamp。