一．选择题：
1．选择题（在正确答案下方划一横道）
低浓度的气膜控制系统，在逆流吸收操作中，若其它操作条件不变，而入口液体组成Xa增高时，则气相总传质单元数将（A增加、B减少、C不变、D不定）,气相总传质单元高度
将（A增加、B减少、C不变、D不定）,气相出口组成将（A增加、B减少、C不变、D不定）液相出口组成将（A增加、B减少、C不变、D不定）
1、L，G不变，不变，故也不变；
mG/L不变，（-mXa）/（-mXa）不变；
若Xa↑，因为〉，故↑；
由图可见Xb的增加。
(2)精馏操作时，若F，D，，q，加料板位置，R都不变，而将塔顶泡点回流改为冷回流，
则塔顶产品组成变化为：（ B）
（A）变小 (B)变大 (C)不变 (D)不确定
7 . ①同一物料，如恒速段的干燥速率增加，则临界含水量：（）。
（A）减小；（B）不变；（C）增大；（D）不一定。
②同一物料，在一定的干燥速率下，物料愈厚，则临界含水量（）。
8 . 原料的数量和浓度相同，用简单蒸馏得汽相总组成为X D1，用平衡蒸馏得汽相总组成为X D2。若两种蒸馏方法所得得汽相量相同，则：X D1> X D2；
11、随温度增加，气体的溶解度（减少），亨利系数E（增加）。
12、在吸收塔某处，气相主体浓度y = 0.025，液相主体浓度x = 0.01，气膜传质分系数k y=2 kmol/(m2?h)，气相总传质系数K y=1.5 kmol/(m2?h) ,平衡关系y = 0.5x。则该处气液界面上气相浓度y i应为(B) 。
(A) 0.02；(B) 0.01；(C) 0.015；(D) 0.005
理由：
15、下列情况中，（4）不是诱发降液管液泛的原因。
（1）液、气负荷过大（2）过量雾沫夹带
（3）塔板间距过小（4）过量漏液。
16、浮阀塔与泡罩塔比较，其最主要的改进是(2)。
(1)简化塔板结构 (2)形成可变气道，拓宽高效操作区域；
(3)提高塔板效率 (4)增大气液负荷
21、二元溶液连续精馏计算中，进料热状态的变化将引起以下线的变化(B)。
（Ａ）平衡线；（Ｂ）操作线与ｑ线；（Ｃ）平衡线与操作线；（Ｄ）平衡线与ｑ线。
23、①湿物料的平衡水份一定是结合水份
②空气温度为t0，湿度为H0，相对湿度为φ0的湿空气，经一间接蒸汽加热的预热器后,空气的温度为t1，湿度为H1，相对湿度为φ1，则有(B )
(A)H1 >H0； (B)φ0 >φ1； (C)H1 ④空气的干球温度为t,湿球温度为tw ,露点为td ,当空气的相对湿度φ=98%时,则(B ) (A)t=t W =t d；(B)t>t w >t d；(C)t 24、吸收塔操作时，若解吸因数mG/L增加，而气液进口组成不变，则溶质回收率将（2），而出塔液体浓度将（4）。（⑴增加；⑵减少；⑶不变；⑷不定）。 26、湿空气在预热过程中不变化的参数是(C)。 (A) 焓；（B）相对湿度；（C）露点温度；（D）湿球温度。 27、在下列哪一根线上露点温度相等？（C） (A) 等相对湿度线； (B) 等热焓线； (C)等湿度线； (D)绝热冷却线 28、对极易溶的气体，气相一侧的界面浓度y i接近于y*。 30、在以下情况中，哪一个属液相扩散控制？（D） (A)平衡线极平（斜率极小）；(B)溶解度系数H极高； (C)平衡线为y=mx，常数m极小；(D)系统服从亨利定律，亨利系数E极高。 33、湿空气在换热器中与另一热介质进行热交换后 (1)如空气温度降低，其湿度肯定不变。(2)如空气温度升高，其湿度肯定不变 则正确的判断是(D)。 (A)两种提法都对（B）两种提法都不对（C）（1）对（2）不对（D）（2）对（1）不对。 36、气、液传质塔设备中，泛点气速应随液相量的增加而下降 43、当湿度和温度一定时，相对湿度与总压的关系成正比 46、被分离物系最小回流比R min的数值与（4）无关。 （1）被分离物系的汽液平衡关系（2）塔顶产品组成 （3）进料组成和进料状态（4）塔底产品组成 二．填空题 1 . ①解吸时溶质由液相向气相传递； ②溶解度很大的气体，属于气膜控制； 在逆流操作的填料吸收塔中，吸收因数A= L/mV 。当A<1时，若填料层高=∞，则气液两相将于塔底达到平衡。 2 . 试述五种不同进料状态下的q值：（1）冷液进料q>1；（2）泡点液体进料q=1；（3）汽液混合物进料0 3 . ①气体通过塔板的阻力可视作是气体通过干板的阻力与气体通过液层的阻力之和。②如果板式塔设计不合理或操作不当，可能产生过量液沫夹带、漏夜及降液管液泛等不正常现象，使塔无法工作。 7 . 干燥传质速率是U＝－GCdx/（Adθ）；干燥传热速率是q＝Q/（Adθ） 已知在t＝50℃、P＝1atm时空气中水蒸汽分压Pv＝55.3mmHg，则该空气的湿含量H＝0.0488；相对湿度φ＝0.598；（50℃时水的饱和蒸汽压为92.51mmHg） 非结合水份是主要以机械方式与物料相结合的水份。 9. 精馏操作的依据是混合液中各组分的挥发度差异。实现精馏操作的必要条件包括塔顶液相回流和塔底上升气流。 10 . ①塔板中溢流堰的主要作用是为了保证塔板上有一定高度的液层。 ②筛板塔、泡罩塔、浮阀塔相比较，操作弹性最大的是浮阀塔；单板压力降最小的是筛板塔；造价最便宜的是筛板塔。 11 . 饱和空气在恒压下冷却，温度由降至，此时其相对湿不变，湿度下降，湿球温度下降，露点下降。 14、对一定操作条件下的填料吸收塔，如将塔料层增高一些，则塔的H OG将不变，N OG将增加17、填料塔是连续接触式气液传质设备，塔内液体为分散相，气体为连续相, 为保证操作过程中两相的良好接触，故填料吸收塔顶部要有良好的液体分布装置。 18、对于为水蒸气所饱和的空气，其干球温度t、湿球温度t w、绝热饱和温度t as及露点温度t d 间的大小关系是：t = t w = t as = t d 。 20、在设计吸收塔时，增加吸收剂用量，将使操作线的斜率变大和吸收过程的推动力(Δy m)变大。 21、通常所讨论的吸收操作中，当吸收剂用量趋于最小用量时，填料层高度趋向无穷大。 24、板式塔从总体上看汽液两相呈逆流接触，在板上汽液两相呈错流接触。 25、恒定的干燥条件是指空气的湿度、温度、速度以及与物料接触的状况都不变。 28、①对不饱和湿空气,干球温度大于湿球温度，露点温度小于湿球温度。 ②干燥操作中，干燥介质（不饱和湿空气）经预热器后湿度不变，温度升高。 ③当物料在恒定干燥条件下用空气进行恒速对流干燥时，物料的表面温度等于空气的湿球温度 29、对气膜控制的系统，气体流量越大，则气相总传质系数K y__越大_，气相总传质单元高度H OG__越大_。 30、某连续精馏塔中，若精馏段操作线方程的截距等于零，则回流比等于__∞_，馏出液量等于_0_； 31、精馏塔中的恒摩尔流假设，其主要依据是各组分的摩尔汽化潜热相等，但精馏段与提馏段的摩尔流量由于进料影响而不一定相等。 32、精馏塔的塔顶温度总低于塔底温度，其原因之一塔顶处易挥发组份浓度大；原因之二塔顶处压力低。 33、评价塔板性能的标准是通过能力大、塔板效率高、塔板压降低、操作弹性大、结构简单制造成本低 36、当精馏操作中的q线方程为x=x F时，则进料热状态为饱和液体，此时q=1。 40、气相中，温度升高则物质的扩散系数增大。 43、直接水蒸汽加热的精馏塔适用于难挥发组分为水，且要求釜液中易挥发组分浓度很低的场合。 44、设计精馏塔时，若增大系统压强，则其相对挥发度将_变小_，塔顶温度将_变大_，塔釜温度将__变大__。 46、饱和空气在恒压下冷却，温度由t1 降至t2，此时下列空气参数的大小变化是：相对湿度_变大_，湿度_不变___，湿球温度__变小_，露点__不变__。 49、①精馏过程是利用多次部分汽化和多次部分冷凝的原理而进行的。 ②精馏过程的回流比是指回流液量与塔顶产品量之比，最小回流比是指塔板数为无限 多时的回流比的极限值 52、①吸收因素A可表示为L/mG ，它在Y-X图上的几何意义是操作线低斜率与平衡线斜率之 比。 ②K x与k x分别是以气相主体的平衡液相摩尔分率与液相主体摩尔分率的之差(即x e-x)和溶质相界面上液相摩尔分率与液相主体摩尔分率之差((即x i-x)为推动力的传质系数，其单位是kmol/m2.s。 53、某二元物系的相对挥发度α=3,在具有理论板的精馏塔内作全回流精馏操作,已知x1=0.3,则y2=0.794(由塔顶往下数)。 解：ｙ2＝αｘ2／[１＋（α－１）ｘ2]＝3×0.3/(1+2×0.3)=0.563 ｘ1＝ｙ2＝０．５６３ ｙ1＝３×0.563／（１＋２×０．５６３）＝0.794 57、在吸收塔的设计中，当气体流量、气相进出口组成和液相进口组成不变时，若减小吸收剂用量，则传质推动力将_减小__，操作线将_靠近_平衡线，设备费用将_增加_。 58、写出吸收操作中对吸收剂的主要要求中的四项溶解度大 ,选择性高, 腐蚀性小,挥发度小 59精馏过程设计时，增大操作压强，则相对挥发度减小，塔顶温度增加，塔釜温度增加。（增大，减小，不变，不确定） 三、简答题 3、影响精馏操作的主要因素是哪些?它们遵循哪些基本关系?影响精馏操作因素的分析 对特定的精馏塔（指全塔板数与加料位置已定，有时加料位置可变动），其操作受诸多因素影响和制约，当某一因素（变量）发生变化时，操作状态随之而变，并调节在新的状态下操作。影响精馏操作的主要因素如下： （1）物系特性和操作压强； （2）生产能力和产品质量（F、D、W、x F、x D、x W）； （3）回流比R和进料热状态参数q； （4）塔设备情况实际板数、加料位置及全塔效率； （5）再沸器和冷凝器热负荷。 上述各因素应遵循的基本关系为： （1）相平衡关系； （2）物料衡算关系； （3）理论板数N T关系，即 （4）塔效率，即（设备结构，负荷，操作条件）； （5）热负荷关系，即。 由上可见，影响精馏操作因素十分复杂，在分析具体过程时，应作适当的简化假定，抓住主要矛盾，利用以上基本关系，作出正确的判断。 精馏的操作计算和设计型计算，遵循的基本关系完全相同，但前者计算更为复杂，一般需要试差计算可图解试差法。精馏的操作型计算在生产中可用预计： （1）操作条件改变时产品质量和采出量的变化； （2）为保证产品质量应该采用什么措施等。 四、计算题 1 .用一连续精馏塔在常压下分离甲醇～水混合物，进料为含甲醇0.41的饱和蒸汽，流率为100Kmol/h。要求塔顶馏出液含甲醇不低于0.95，塔底釜液甲醇不大于0.05（以上均为摩尔分率），已知操作条件下的平衡关系如附图，操作时回流比为2.4，试求：（1）塔顶、塔底产品的流率； （2）所需理论塔板数及进料板位置； （3）两端的液相流率与汽相流率比和q线方程； （4）对应的最小回流比。 解：（1）物料衡算： F＝D＋W （a） F x F＝D x D＋W x W（b） 由（a）得W＝F－D 则：F x F＝D x D＋（F－D）x W 100×0.41＝D×0.95＋（100－D）×0.05 41＝0.95D＋5－0.05D D＝36/0.9＝40Kmol/h W＝100-40＝60 Kmol/h （2）精馏段操作方程： y＝（R/（R＋1）x＋x D/（R＋1） x D/（R＋1）＝0.95/（2.4＋1）＝0.279≈0.28 提馏段的操作方程： y′＝（（L＋q F）/（L＋q F－W））x′－WxW/（L＋q F－W） L＝RD＝2.4×40＝96Kmol/h Q线y＝（q/（q－1））x－x F/（q－1） y=x F 由图解得：N T＝6-1＝5（不含釜），进料位置Nf＝5 （3）V＝L＋D＝96＋40＝136 Kmol/h L/V＝96/136＝0.706 L′/V′＝L/V′＝L/（V－（1-q）F ＝96/（136-100）＝2.67 （4）R min /（R min ＋1）＝（y D －y 0）/（x D －x 0） ＝（0.95-0.41）/（0.95-0.1）＝0.6353 R min ＝（0.6353 R min ＋0.6353 R min ＝0.6353/（1-0.6353）＝1.742 2、用板式塔在常压下进行连续精馏分离苯－甲苯混合物溶液，塔顶设置全凝器，塔釜间接蒸汽加热，平均相对挥发度为2.47 。进料为流量150Kmol/h 、含苯0.4（摩尔分率，下同）甲苯0.6的饱和液体，塔顶液体回流比为3 。要求塔顶馏出液中苯的组成为0.98 ，并且苯的回收率达到97% 。 （1）（5分）计算馏出液的流量和釜液的流量、釜液中苯的组成； （2）（5分）计算最小回流比； （3）（5分）计算精馏段中的液相流量、汽相流量，写出精馏段操作线方程； （4）（5分）计算提馏段中的液相流量、汽相流量，写出提馏段操作线方程。 解：（1）（5分）F Fx Dx D = η ， 4.015098.097.0?=D ， h /Kmol 4.59=D ， h /Kmol 6.90=-=D F W 02.0D F W =-= W Dx Fx x （2）（5分）1=q ， 4.0F e ==x x ， 62.04.047.114 .047.2)1(1e e =?+?=-α+α= e x x y ， 62.14 .0622.0622.098.0e e e D min =--=--=x y y x R （3）（5分），3=R h /Kmol 2.178==RD L ，h /Kmol 6.237)1(=+=D R V ， 4 98 .04311+=+++= x R x x R R y D （4）（5分）1=q ，h /Kmol 150=F ，h /Kmol 2.328=+=qF L L ， h /Kmol 6.237)1(=--=F q V V 6 .23702 .06.906.2372.328W ?-=-= x V Wx x V L y 3、在常压连续精馏塔内分离苯和甲苯混合液，混合液的流量为1000kmol/h ，其中含苯40%， 要求塔顶馏出液中含苯90%，塔釜残液中含苯2%（均为摩尔分率）。泡点进料，塔顶冷凝器为全凝器，塔釜间接蒸汽加热，取回流比为最小回流比的1.5倍。全塔平均相对挥发度为2.5。试求： （1） 塔顶与塔底产品量D 、W ； （2） 回流比R ； （3） 精馏段操作线方程； （4） 从上往下数的塔内第二块理论板上升气体组成； （5） 若在塔操作中，将进料状态改为饱和蒸汽进料，而保持F 、R 、D 、x F 不变，此时能否完成分离任务？简单分析为什么？ ……………试……………题……………不……………要……………超……………过……………此……………线……… 解：（1）即 解之得：D=431.82kmol/h W=568.18kmol/h （2）泡点进料， （3）精馏段操作线方程： （4）F、R、D不变，而进料状态由饱和液体改为饱和蒸汽时，q↓E随 q↓，提馏段塔板分离能力↓ x W必，又由全塔物料衡算可知，x D↓ 4、用填料塔从一混合气体中吸收苯。进塔混合气体含苯5% （体积百分数），其余为惰性气体。回收率为95%。操作压强为104kPa，温度为25℃，进塔的混合气体量为1000 m3/h。吸收剂为不含苯的煤油，煤油的耗用量为最小用量的1.5倍，气液逆流流动。已知该系统的平衡关系为Y＝0.14X（式中Y、X均为摩尔比），气相总体积传质系数K Y a=125kmol/(m3?h)，煤油的平均分子量为170，塔径为0.6m。试求： (1)煤油的耗用量，kg/h； (2)煤油的出塔浓度x1（摩尔分率）； (3)填料层高度； (4)欲提高回收率，可采用那些措施？（简单说明理由） 解：(1)； (2) (3) (4) 欲提高回收率，可增大液相流率、增大塔高、提高操作压力等。 增大液相流率，可增大液相侧湍动程度、降低总传质阻力，从而提高传质速率和回收率。增大塔高，可使气液传质面积增大，增大传质量，从而提高回收率。提高操作压力，可使相平衡常数变小，从而增大传质推动力，提高传质速率和回收率。 5、 某厂有一填料塔，直径为1m ，填料层高6m ，填料为某种瓷拉西环乱堆。用该塔处理含有少量丙酮的空气。每小时处理气体2240m 3（体积为0 ℃ 、101.33KPa 时的值，此状况下每1kmol 的体积为22.4m 3），其中含丙酮（摩尔分数，下同）为05.0 。用清水作吸收剂。塔顶送出的空气含丙酮降为0025.0,自塔底流出的溶液经分析为02.01=x 。操作条件下的相平衡关系为A A 0.2x y = 。根据上述测试数据计算： （1）（5分）塔内作为吸收剂的水的流量Kmol/h ； （2）（5分）塔内气相传质单元数； （3）（5分）该填料的容积传质系数a K y ，以 3 m h Km ol ?表示。 解：（1）（5分）G=100kmol/h ， y 1=0.05 ， y 2=0.0025 ， h /K m o l 75.4)(21=-y y G （2）（5分）h /Kmol 5.237)(2 121=--=x x y y G L （3）（5分）01.002.0205.0111=?-=-=?mx y y 0025.0022=-=?y y 0075.0ln 2 121m =???-?=?y y y y y 33.60075 .00025 .005.0m 21OG =-=?-= y y y N 或者 =??????+--??? ??-- = 5.23720000025.0005.05.2372001ln 5 .23720011OG N 6.33 （4）（5分） m 95.033 .664y 2 OG OG ==π==a K D G N H H ，32 y m h Kmol 1.13495.04?=π=D G a K 2013年12月大学英语四级听力真题 PartⅡListening Comprehension(30 minutes) Section A Directions: In this section, you will hear 8 short conversations and 2 long conversations. At the end of each conversation, one or more questions will be asked about what was said. Both the conversation and the questions will be spoken only once. After each question there will be a pause. During the pause, you must read the four choices marked A), B), C) and D), and decide which is the best answer. Then mark the corresponding letter on Answer Sheet 1 with a single line through the centre. 1. A) The woman is now working in a kindergarten. B) The man will soon start a business of his own. C) The man would like to be a high school teacher. D) The woman is going to major in child education. 2. A) The furniture has to be rearranged. B) The sound equipment has to be set up. C) The conference room has to be cleaned. D) The video machine has to be checked. 3. A) She is exhausted. B) She is near-sighted. C) She cannot finish work in time. D) She cannot go straight home. 4. A) The woman is too particular about food. B) He would rather have a meal an hour later. C) The woman should order her food quickly. D) He usually prefers ice-cream to sandwiches. 5. A) He is not a good mechanic. B) He doesn't keep his promises. C) He spends his spare time doing repairs. D) He is always ready to offer help to others. 6. A) Sam has a big family to support. B) Sam is not interested in traveling. C) The pay offered by the travel agency is too low. D) The work hours in the travel agency arc too long 7. A) International trade. 2017年12月大学英语四级真题及答案(第三套) Part I Writing (25 minutes) Directions: For this part, you are allowed 30 minutes to write a short essay onhow to best handle the relationshop between teachers and students. You should write at least 120 words but no more than 180 words. Part II Listening Comprehension (25 minutes) Section A Directions: In this section, you will hear three news reports. At the end of each news report, you will hear two or three questions. Both the news report and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C) and D). Then mark the corresponding letter on Answer Sheet 1 with a single line through the centre. Questions 1 and 2 are based on the news report you have just heard. 1. A) Her friend Erika. C) Her grandfather. 四级真题答案（网友版） 听力答案 短对话 11-14 A) B) A) D) 15-18 D) C) C) B) 长对话 conversation one 19. D) 20. A) 21. D) conversation two 22.D) 23. B) 24. B) 25. B) 短文 passage one 26. C) 27. C) 28. D) passage two 29. D) 30. A) 31. C) passage three 32. A) 33. A) 34. A) 35. C) 复合式听写 36. survive 37. distant 38. backward 39. discovered 40. scientific 41. motion 42. predicted 43. introduced 44. that move at a speedgreater than light. And therefore, might serve as our passports tothe past 45. seems to have been a part of humanity for aslong as human have existed 46. used adefinition of time for experimental purposes, as that which ismeasured by a clock 听力原文： 短对话 11. M：Sean has been trying for month to find a job, but I wonder how he could get a job when he looks like that. W: Oh, poor guy, he really should shave himself every other day at least, and put on something clean. Q: What do we learn about Sean? 12. W: I wish Jane would call when she know she’ll be late. This is not the first time we had to wait for her. M: I agree, but she does have to drive through very heavy traffic to get here. Q: What does the man imply? 2017年12月大学英语四级考试真题及答案（第一套）Part I Writing （25 minutes） Directions: For this part, you are allowed 30 minutes to write a short easy on how to best handle the relationship between doctors and patients. You should write at least 120 words but no more than 180 words. Part II Listening Comprehension （25 minutes） Section A Directions: In this section, you will hear three news reports. At the end of each news report, you will hear two or three questions. Both the news report and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C) and D). Then mark the corresponding letter on Answer Sheet 1 with a single line through the centre. Questions 1 and 2 are based on the news report you have just heard. 1. A) Her friend Erika. C) Her grandfather. B) Her little brother. D) Her grandmother. 2. A) By taking pictures for passers-by. C) By selling lemonade and pictures. B) By working part time at a hospital. D) By asking for help on social media. Questions 3 and 4 are based on the news report you have just heard. 3. A) Finding cheaper ways of highway construction. B) Generating electric power for passing vehicles. C) Providing clean energy to five million people. D) Testing the efficiency of the new solar panel. 4. A) They can stand the wear and tear of natural elements. B) They can be laid right on top of existing highways. C) They are only about half an inch thick. D) They are made from cheap materials. Questions 5 to 7 are based on the news report you have just heard. 5. A) Endless fighting in the region. C) Inadequate funding for research. B) The hazards from the desert. D) The lack of clues about the species. 6. A) To observe the wildlife in the two national parks. B) To identify the reasons for the lions’ disappearance. C) To study the habitat of lions in Sudan and Ethiopia. 2010年12月大学英语四级听力真题的试题与答案, Section A 短对话(11~18) 11. M: Oh my god! The heat is simply unbearable here. I wish we’ve gone to the beach instead. W: Well, with the museums and restaurants in Washington I’ll be happy here no matter what the temperature. Q：What does the woman mean? 12. M: How’s the new job going? W: Well, I’m learning a lot of new things, but I wish the director would give me some feedback. Q：What does the woman want to know? 13. M: Can you help me work out a physical training program John? W: Sure, but whatever you do be careful not to overdo it. Last time I had two weeks’ worth of weight-lifting in three days and I hurt myself. Q: What does the man suggest the woman do? 14. M: I have an elderly mother and I’m worried about her going on a pl ane. Is there any risk? W: Not if her heart is all right. If she has a heart condition, I’d recommend against it. Q: What does the man want to know about his mother? 15. M: Why didn’t you stop when we first signaled you at the crossroads? W: Sorry, I was just a bit absent-minded. Anyway, do I have to pay a fine? Q: what do we learn from the conversation? 16. M: I’m no expert, but that noise in your refrigerator doesn’t sound right. Maybe you should have it fixed. W: You’re right. And I suppose I’ve put it off long enough. Q: What will the woman probably do? 17. M: I did extremely well on the sale of my downtown apartment. Now, I have enough money to buy that piece of land I’ve had my eye on and build a house on it. W: Congratulations！Does that mean you’ll be moving soon? Q: What do we learn about the man from the conversation? 大学英语四级考试真题及答案(绝对完整） Part I Writing (30 minutes) Directions: For this part, you are allowed 30 minute to write a short essay on the topic of students selecting their lectures. You should write at least 120 words following the outline given bellow: 1. 越来越多的博物馆免费对外开放的目的是什么？ 2. 也会带来一些问题 3. 你的看法？ Part II Reading Comprehension (Skimming and Scanning) (15 minutes)Directions: In this part, you will have 15 minutes to go over the passage quickly and answer the questions on Answer Sheet 1. For questions 1-7, choose the best answer from the four choices marked A),B),C) and D). For questions 8-10, complete the sentences with the information given in the passage. How Do You See Diversity? As a manager, Tiffany is responsible for interviewing applicants for some of the positions with her company .During one interview, she noticed that the candidate never made direct eye contact. She was puzzled and somewhat disappointed because she liked the individual otherwise. He had a perfect resume and gave good responses to her questions, but the fact that he never looked her in the eye said “untrustworthy,” so she decided to offer the job to her second choice. “It wasn’t until I attended a diversity workshop that I realized the person we passed over was the perfect person,” Tiffany confesses. What she hadn’t known at the time of the interview was that the candidate’s “different” behavior was simply a cultural misunderstanding . He was an Asian-American raised in a household where respect for those in authority was shown by averting(避开) your eyes. “I was just thrown off by the lack of ye contact; not realizing it was cultural,” Tiffany says. “I missed out ,but will not miss that opportunity again.” Many of us have had similar encounters with behaviors we perceive as different. As the world becomes smaller and our workplaces more diverse, it is becoming essential to expand our under-standing of others and to reexamine some of our false assumptions . Hire Advantage At a time when hiring qualified people is becoming more difficult ,employers who can eliminate invalid biases(偏爱) from the process have a distinct advantage .My company, Mindsets LLC ,helps organizations and individuals see their own blind spots . A real estate recruiter we worked with illustrates the positive difference such training can make . 2011年6月英语四级真题与答案 Part I Writing Doing Shopping Online With the development of the Internet, shopping is no longer a tiring thing. Just click your mouse to choose the articles you like, and the purchase is done. You don’t even have to step out of the room. It seems all easy and quick. However, people’s opinions vary on this trend. Some believe that on line shopping is time and money saving. With plentiful selection options, they can buy whatever they like at any time convenient. Still others insist that mis-purchasing alone is annoying enough, not to mention the credibility of the sellers and the safety of their accounts. In my opinion, the convenience and excitement of on line shopping is beyond all doubts. In the meantime, we must always bear in mi nd that certain traps do exist, so we’d better make sure the sellers are trustworthy before buying. In addition, we should also guard ourselves from the potential hackers who might steal our account information. 文章点评： 这是一篇“中等偏上”的学生作文。本文先对网购热潮进行简介，引出全篇；接着对网络购物的正反两方面进行对比；最后提出自己的看法结束全篇。整体看思路清晰，逻辑严密，行文流畅，用语较为地道。 下面说一下这篇文章的有待提高之处： 1. 文章结构上，能看得出该同学试图采用议论文的“三段式”（提出问题、分析问题、解决问题）。但是，以“With the development of the Internet”为开首语，有些落入俗套，有硬套模板的嫌疑。稍加注意，应该能写出更好的句子。 2. 微观语言点方面，有些语句稍显啰嗦，比如With plentiful selection options… 简化成With plentiful selections… 更好，意思没有丝毫减损，表达力反而增强许多； 高分版 With the help of the ever rapid development of internet technology, online shopping is coming into fashion in most of cities. Online shopping is welcomed by most people due to various reasons. From the perspective of consumer, it can save some time for people who don’t have much spare time. Just click the mouse, they can get whatever they want while staying at home. For the retailers, it can cut some costs for those who don’t have much circulating funds. They don’t have to rent a house and spend money on 2016年6月大学英语四级真题（第1套） Part I Writing (30 minutes) Directions: For this part, you are allowed 30 minutes to write a letter to express your thanks to your parents or any family members upon making memorable achievement. You should write at least 120 words but no more than 180 words. Part Ⅱ Listening Comprehension (25 minutes) Section A Directions: In this section, you will hear three news reports. At the end of each news report, you will hear two or three questions. Both the news report and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C) and D). Then mark the corresponding letter on Answer Sheet 1 with a single line through the centre. Questions 1 and 2 are based on the news report you have just heard. 1. A)The International Labor Organization's key objective. B)The basic social protection for the most vulnerable. C)Rising unemployment worldwide. D)Global economic recovery. 2. A)Many countries have not taken measures to create enough jobs. B)Few countries know how to address the current economic crisis. C)Few countries have realized the seriousness of the 2014-2019历年大学英语四级真题及答案 2014年6月大学英语四级考试真题 Part I Writing （30 minutes） Directions: For this part, you are allowed 30 minutes to write a short essay on the following question. You should write at least 120 words but no more than 180 words. Suppose a foreign friend of yours is coming to visit China, what is the first place you would like to take him/her to see and why? Part II Listening Comprehension （30 minutes） Section A Directions: In this section, you will hear 8 short conversations and 2 long conversations. At the end of each conversation, one or more questions will be asked about what was said. Both the conversation and the questions will be spoken only once. After each question there will be a pause. During the pause, you must read the four choices marked A）, B）, C）and D）, and decide which is the best answer. Then mark the corresponding letter on Answer Sheet 1 with a single line through the centre. 1. A）The man should visit the museums. B）She can’t stand the hot weather. C）The beach resort is a good choice. D）She enjoys staying in Washington. 2. A）Her new responsibilities in the company. B）What her job prospects are. C）What the customers’ feedbac k is. D）The director’s opinion of her work. 3. A）Combine her training with dieting. B）Repeat the training every three days. C）Avoid excessive physical training. D）Include weightlifting in the program. 4. A）When she will return home. B）Whether she can go by herself. C）Whether she can travel by air. D）When she will completely recover. 5. A）The woman knows how to deal with the police. B）The woman had been fined many times before. C）The woman had violated traffic regulations. D）The woman is good at finding excuses. 6. A）Switch off the refrigerator for a while. B）Have someone repair the refrigerator. C）Ask the man to fix the refrigerator. D）Buy a refrigerator of better quality. 7. A）He owns a piece of land in the downtown area. B）He has got enough money to buy a house. C）He can finally do what he has dreamed of. D）He is moving into a bigger apartment. 8. A）She is black and blue all over. B）She has to go to see a doctor. C）She stayed away from work for a few days. D）She got hurt in an accident yesterday. I. Listening. (15’) 1. Listen to the recording and write the missing expressions. (5’) 1 ) In general ___________ ____________ ____________ you are thinking of … 2) ____________, _____________ ______________ make sure that the brand is strong. 3) ____________ _____________, making and selling pizzas might be profitable but… 4) I ____________ ______________ you need to like hard work. 5) _____________, _____________ the money. You … 2. Listen to the recording and choose the best ending for each sentence. 1) The speaker compares throwing adverts into the air to __________. A) Internet advertising B) wasting money on adverting C) advertising with leaflets 2) His first piece of advice is to _____________. A) make sure people find you on the search engine B) make sure people visit the search engine C) set up a search engine 3) Spend plenty of time on ____________. A) promoting others on your site B) creating links to incrase traffic C) recommending your product on other site 4) The speaker _____________. A) thinks email can be effective B) is doubtful about using email C) never sends marketing emails 5) It’s good idea to ___________. A) give free samples away at the beginning B) make the website free to visit C) offer something free to encourage people to return II. Write the verbs in brackets in their correct form to complete the following sentences. 1. Now that you _____________ (escape) from the office, you will still need peace and quiet at home. 2. Once you __________________ (work) from home for a while, you might feel a bit lonely. 3. I’m just phoning to confirm that I _______ (be) in my office by ten. 4. Don’t worry. I promise that I _______(call) back straight away. 5. Security ___________ (open) the building at eight tomorrow instead of nine. 6. The hotel has a scheduled shuttle bus to the training center. I think it ________ (leave) every half hour, but let me check for you. 7. We began at nine. So by the time he arrives at nine thirty, the first session _________ (start). 8. She showed him the photo she _______ (take) the day before. 9. It’s the third time I ______ (see) him this month. 10. We _____ (meet) each other since I left Shanghai. III. Complete the following sentences with the words or phrases given below. sample mailshots word of mouth see move hold set run attend reach Part I Writing (30 minutes) Directions:For this part, you are allowed 30 minutes to write a short essay on the importance of writing ability and how to develop it. You should write at least 120 words but no more than 180 words. ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ Part II Listening Comprehension (25 minutes) Section A Directions:In this section, you will hear three news reports. At the end of each news report, you will hear two or three questions. Both the news report and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C) and D). 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