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问题 选择题

2008年，美籍华裔化学家钱永健获得该年度诺贝尔化学奖。少年时代，他就对化学产生了浓厚的兴趣。16岁时，他凭借一个金属易受硫氰酸盐腐蚀的调查项目，荣获具有“小诺贝尔奖”之称的“西屋科学天才奖”。下列说法正确的是

A．金属腐蚀就是金属原子失去电子被还原的过程

B．合金都比纯金属易被腐蚀

C．将金属与外加直流电源的负极相连，而将正极接到废铁上，可以防止金属被腐蚀

D．镀锌铁比镀锡铁更容易被腐蚀

答案

C　

金属腐蚀过程中金属原子失去电子被氧化，A项不正确；不锈钢属于铁、镍、铬等的合金，它比纯铁耐腐蚀，B项不正确；将金属与外加直流电源的负极相连，金属可被保护，C项正确；镀锌铁在镀层破损后，由于锌比铁活泼，锌作负极被腐蚀但铁被保护，镀锡铁在镀层破损后，由于铁比锡活泼，铁作负极而被腐蚀，因此镀锡铁比镀锌铁更容易被腐蚀，D项不正确。故答案为C项。

多项选择题

关于产后出血，叙述正确的有（）。

A.产后2h是产后出血发生的高峰

B.产后出血是分娩晚期严重的并发症

C.引起产后出血的最主要原因是胎盘滞留

D.产后膀胱过度充盈引起的出血应及时导尿

E.子宫收缩乏力引起的产后出血可应用缩宫素加强宫缩
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问答题

The treasury division of Marengo Co,a large quoted company,holds equity investments in various companies around the world.One of the investments is in Arion Co,in which Marengo holds 200，000 shares,which is around 2% of the total number of Arion Co’s shares traded on the stock market.Over the past year,due to the general strength in the equity markets following optimistic predictions of the performance of world economies,Marengo’s investments have performed well.However,there is some concern that the share price of Arion Co may fall in the coming two months due to uncertainty in its markets.It is expected that any fall in share prices will be reversed following this period of uncertainty.The treasury division managers in Marengo,Wenyu,Lola and Sam,held a meeting to discuss what to do with the investment in Arion Co and they each made a different suggestion as follows:1.Wenyu was of the opinion that Marengo’s shareholders would benefit most if no action were taken.He argued that the courses of action proposed by Lola and Sam,below,would result in extra costs and possibly increase the risk to Marengo Co.2.Lola proposed that Arion Co’s shares should be sold in order to eliminate the risk of a fall in the share price.3.Sam suggested that the investment should be hedged using an appropriate derivative product.Although no exchange-traded derivative products exist on Arion Co’s shares,a bank has offered over-the-counter (OTC)option contracts at an exercise price of 350 cents per share in a contract size of 1，000 shares each,for the appropriate time period.Arion Co’s current share price is 340 cents per share,although the volatility of the share prices could be as high as 40%.It can be assumed that Arion Co will not pay any dividends in the coming few months and that the appropriate inter-bank lending rate will be 4% over that period.Required:

(a)Estimate the number of OTC put option contracts that Marengo Co will need to hedge against any adverse movement in Arion Co’s share price.Provide a brief explanation of your answer.Note: You may assume that the delta of a put option is equivalent to N(–d1)(7 marks)
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