对于反应A+3B=2C+D来说,下列反应速率中最快的是 [ ] A.v(A)=0

题型:选择题

问题:

对于反应A+3B=2C+D来说,下列反应速率中最快的是 [ ]

A.v(A)=0.3mol·L-1·min-1

B.v(B)=0.6mol·L-1·min-1

C.v(C)=0.5mol·L-1·min-1

D.v(D)=0.001mol·L-1·min-1

考点:化学反应速率的计算
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现有Ca(OH)2、Na2CO3、BaCl2、NaOH、盐酸、稀硫酸六种溶液,有如下图所示的相互反应关系,图中每条线两端的物质可以发生化学反应,试将它们的化学式填入图中相应的六个方框中。

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When families gather for Christmas dinner, some will stick to formal traditions dating back to grandma’s generation. Their tables will be set with the good dishes and silver, and the dress code will be Sunday best.

But in many other homes, this china-and-silver elegance has given way to a stoneware (粗陶) and stainless informality, with dresses assuming an equally casual-Friday look. For hosts and guests, the change means greater simplicity and comfort. For makers of fine china in Britain, it spells economic hard times.

Last week Royal Doulton, the largest employer in Stoke-on-Trent, announced that it is eliminating 1,000 jobs-one-fifth of its total workforce. That brings to more than 4,000 the number of positions lost in 18 months in the pottery (陶瓷) region. Wedgwood and other pottery factories made cuts earlier.

Although a strong pound and weak markets in Asia play a role in the downsizing, the layoffs in Stoke have their roots in earthshaking social shifts. A spokesman for Royal Doulton admitted that the company “has been somewhat slow in catching up with the trend” toward casual dining. Families eat together less often, he explained, and more people eat alone, either because they are single or they eat in front of television.

Even dinner parties, if they happen at all, have gone casual. In a time of long work hours and demanding family schedules, busy hosts insist, rightly, that it’s better to share a takeout pizza on paper plates in the family room than to wait for the perfect moment or a “real” dinner party. Too often, the perfect moment never comes. Iron a fine-patterned tablecloth? Forget it. Polish the silver? Who has time?

Yet the loss of formality has its down side. The fine points of etiquette (礼节) that children might once have learned at the table by observation or instruction from parents and grandparents (“Chew with your mouth closed.” “Keep your elbows off the table.”) must be picked up elsewhere. Some companies now offer etiquette seminars for employees who may be able professionally but inexperienced socially.

67.Why do people tend to follow the trend to casual dining?

A. Family members need more time to relax.

B. Busy schedules leave people no time for formality.

C. People prefer to live a comfortable life.

D. Young people won’t follow the etiquette of the older generation

68.It can be learned from the passage that Royal Doulton is ________.

A. a seller of stainless steel tableware                      B. a dealer in stoneware

C. a pottery chain store                                                 D. a producer of fine china

69.The main cause of the layoffs in the pottery industry is ________.

A. the increased value of the pound                          

B. the worsening economy in Asia

C. the change in people’s way of life

D. the fierce competition at home and abroad

70.Formal table manners, though less popular than before in current social life, ________.

A. are still a must on certain occasions                     B. are certain to return sooner or later

C. are still being taught by parents at home                    D. can help improve personal relationships

题型:选择题

颈、腰段活动范围中,下列哪项是错误的()。

A.颈椎前屈后伸均为35°

B.颈椎左右侧屈均为305°

C.腰椎前屈455°

D.腰椎后伸355°

E.腰椎左右侧屈均为305°

题型:选择题

对软件系统进行各级测试所需要的软硬件设备和支持是属于哪一种测试环境

A) 软件测试设计环境
B) 软件测试实施环境
C) 软件测试管理环境
D) 软件测试规划环境

题型:选择题

下列哪项不属于清热药抗菌有效成分()

A、小檗碱

B、苦参碱

C、绿原酸

D、原儿茶酸

E、癸酰乙醛

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