问题 选择题

已知在常温下测得浓度均为0.1 mol·L-1的下 * * 种溶液的pH:

溶质NaHCO3Na2CO3NaCN
pH9.711.611.1
 

下列说法中正确的是(  )

A.阳离子的物质的量浓度之和:

Na2CO3>NaCN>NaHCO3

B.相同条件下的酸性:H2CO3<HCN

C.三种溶液中均存在电离平衡和水解平衡

D.升高Na2CO3溶液的温度,减小

答案

答案:C

阳离子均为Na和H,Na2CO3溶液中Na浓度是其他两种溶液的两倍,阳离子浓度最大,NaCN溶液和NaHCO3溶液中Na浓度相等,NaCN溶液中H浓度小于NaHCO3溶液,故阳离子浓度大小顺序为Na2CO3>NaHCO3>NaCN,A项错误;HCO3-的水解能力小于CN,故酸性:H2CO3>HCN,B项错误;升高Na2CO3溶液的温度,促进其水解,增大,D项错误。

综合题

(18分)东西方经济发展水平的比较研究,是一个热门话题。阅读下列材料,结合所学知识,回答问题。

统计时间人口(亿人)人均耕地面积(市亩)粮食亩产量(市斤)人均农业收入(市斤)
战国晚期(约公元前240年)0.8464.23216914
西汉末(约(公元元年)2.2403.76264993
唐初((约公元700年)1.9903.763341256
宋初(约公元1000年)3.9003.753091159
明中叶(约公元1500年)4.2003.284541118
清中叶(约公元1800年)6.1901.71460628
材料一 中国历代粮食亩产量和农民劳动生产率

资料来源:吴慧:《中国历代粮食亩产研究》

材料二 中国与西欧人均国民收入的比较(400—1900)

资料来源:安格斯·麦迪森:《世界经济千年史》

材料三 当一种领先世界的文明发展到巅峰后,如果产生高度特化适应和内向成长的惰性,就会因保守而难于实现社会转型,受到“先进的惩罚”,逐渐落后。相反,后进者因自身文明的不完善,改善生活条件,发展生产能力的要求得到激励,往往会在下一阶段的赛跑中具有“借用的优惠”。

——庞卓恒《史学理论》

(1)根据材料一指出,明清时期,我国粮食亩产量相比前代有何变化?结合所学知识,分析造成这一变化的原因。(4分)

(2)根据材料一,概括从战国到清中叶人均农业收入发展变化趋势。材料二中,公元700年到公元1500年人均国民收入变化趋势,与材料一中农业收入变化趋势有何不同?结合所学知识,分析造成这一不同的原因。(6分)

(3)综合上述材料,结合所学知识,谈谈你对材料三中观点的理解。(8分)

单项选择题

It was a ruling that had consumers seething with anger and many a free trader crying foul. On November 20th the European Court of Justice decided that Tesco, a British supermarket chain, should not be allowed to import jeans made by America’s Levi Strauss from outside the European Union and sell them at cut-rate prices without getting permission first from the jeans maker. Ironically, the ruling is based on an EU trademark directive that was designed to protect local, not American, manufacturers from price dumping. The idea is that any brand-owning firm should be allowed to position its goods and segment its markets as it sees fit: Levi’s jeans, just like Gucci handbags, must be allowed to be expensive.

Levi Strauss persuaded the court that, by selling its jeans cheaply alongside soap powder and bananas, Tesco was destroying the image and so the value of its brands—which could only lead to less innovation and, in the long run, would reduce consumer choice. Consumer groups and Tesco say that Levi’s case is specious. The supermarket argues that it was just arbitraging the price differential between Levi’s jeans sold in America and Europe—a service performed a million times a day in financial markets, and one that has led to real benefits for consumers. Tesco has been selling some 15,000 pairs of Levi’s jeans a week, for about half the price they command in specialist stores approved by Levi Strauss. Christine Cross, Tesco’s head of global non-food sourcing, says the ruling risks "creating a Fortress Europe with a vengeance".

The debate will rage on, and has implications well beyond casual clothes (Levi Strauss was joined in its lawsuit by Zino Davidoff, a perfume maker). The question at its heart is not whether brands need to control how they are sold to protect their image, but whether it is the job of the courts to help them do this. Gucci, an Italian clothes label whose image was being destroyed by loose licensing and over-exposure in discount stores, saved itself not by resorting to the courts but by ending contracts with third-party suppliers, controlling its distribution better and opening its own stores. It is now hard to find cut-price Gucci anywhere.

Brand experts argue that Levi Strauss, which has been losing market share to hipper rivals such as Diesel, is no longer p enough to command premium prices. Left to market forces, so-so brands such as Levi’s might well fade away and be replaced by fresher labels. With the courts protecting its prices, Levi Strauss may hang on for longer. But no court can help to make it a great brand again.

Which of the following is not true according to Paragraph 1 ()

A.Consumers and free traders were very angry

B. Only the Levi’s maker can decide the prices of the jeans

C.The ruling has protected Levi’s from price dumping

D. Levi’s jeans should be sold at a high price