在我国，某交易者在4月28日卖出10手7月份白糖期货合约同时买入10手9月份白糖期货合约，价格分别为5350元/吨和5400元/吨。5月5日该交易者对上述合约全部对冲平仓7月和9月合约平仓价格分别为5380元/吨和5480元/吨。该套利交易（ ）元。（白糖期货交易单位为10吨/手，不计手续费等费用）

style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/B． Success breeds imitators. Amazon is about to be attacked by a squadron of would-be Kindle killers being brought to market by some of the biggest names in consumer electronics and publishing. To complicate the increasingly competitive landscape even further, Apple and, according to rumor, Microsoft are working on tablet computers that could prove to be handy e-readers but with more functions and features, such as video display capability and full web browsers. "2009 is a breakout year fore-readers," says Sarah Rotman Epps, an analyst with Forrester Research."But we're still in the early stages."
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/C． The early stages have lasted a longtime. E-readers have been around for more than a decade, but the devices weren't popular due to high cost, proprietary (专利的) display formats and the reluctance of book publishers to sell digital versions of their best-selling titles. Now, just as digital music was driven into the mainstream by Apple's iPod and iTunes, Amazon's Kindle andonline bookstore, which sells more than 350,000 titles, are proving there's amass market for e-books. Total industry revenue from digital-book downloads has risen 149% this year, according to the Association of American Publishers,while e-reader sales are expected to reach 3 million by Dec.31, according to For rester Research. Almost a million of the devices could be sold during the upcoming holiday season alone. In 2010, sales are projected to double, to 6 million.That kind of growth is hard to come by in the recession-wracked technology industry, and a crowd is starting to gather. Around the world, at least 17 e-readers are in development or already on the market.
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/D． Among the better-known entrants is Asustek -- the Taiwanese company of China practically invented the netbook category with its ASUS Eee-PC, and it is working on a product called the Eee-reader that it hopes to have on the market in time for Christmas. South Korea's two powerhouse consumer-electronics companies, Samsung and LG Electronics, are wading in too. Samsung earlier this year introduced a reader called the Papyrus in South Korea; reports circulating in the technology blogosphere say LG is developing a prototype with a large,11.5- inch (diagonal） flexible screen. Meanwhile, Japan's Fujitsu has released the world's first dedicated e-reader with a colour  screen, although so far the device is only available in Japan.
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/E． It isn't just tech companies that are joining the fray. Bricks-and-mortar bookseller Barnes & Noble, which in the US offers access to 750,000 e-books on its website, is rumored to be pondering the development of its own e-reader to rival the Kindle. (The retailer already has a partnership to sell e-readers made by IREX, a spin-off of Holland's Royal Philips Electronics.)
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/Major newspaper and magazine publishers,which are suffering mightily from the loss of subscribers and advertisers to the recession and the Internet, are also getting involved. News Corp. chairman and CEO Rupert Murdoch, owner of The Wall Street Journal, is reportedly considering a deal with Japanese consumer-electronics giant Sony, which in 2004 introduced the first commercially viable e-reader, to use a black-and-white display technology called electronic ink (also used by the Kindle. Sony is rolling out a new family of e-readers, including a pocket- size version and one with a large screen that's geared toward newspapers and magazines.
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/F． One reason e-readers are getting traction is that competition is driving down prices. Amazon has cut the price of the Kindle by $100 over the past six months, to $259. As e-readers proliferate(激增) and price disparities narrow, manufacturers are trying to differentiate their products by adding features such as MP3 players and touch screens. The eSlick by Foxit,based in Fremont, Calif., allows users to listen to songs while reading .Asustek recently unveiled a prototype e-reader with two screens, which would more closely duplicate the traditional reading experience, although the devicethat the company expects to release later this year will have a single screen.
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/G． At the same time, new display technologies are emerging that promise to improve battery life and make devices more portable and easier to read. UK-based Plastic Logic hopes to introduce nextyear the first e-reader with a plastic screen that will reduce glare and be less prone to cracking when dropped by ham-fisted owners. Electronic-ink technology is set to move from black and white to colour by the end of 2010.Even video is on the horizon. "We'll see a range of models start to appear over the first half of 2010 offering a range of different reading and productivity experiences," says Neil Jones, CEO of UK-based In teread, which in May launched
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/a $249 e-reader called the COOL-ER.
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/H. Newcomers will have a hard time breaking Amazon's chokehold in the US, where the company controls 60% of the e-reader market, according to Forrester Research. But the edge Amazon gained when it launchedthe Kindle could be blunted by evolving technology and changing consumer needs.Currently, more people read e-books on their smart phones than they do on dedicated devices like e-readers.
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/I. And there's the looming threat posed by next-generation tablet computers. Apple, the king of cool handheld devices, is rumored to be readying a tablet computer with all the functions of a laptop aswell as iPhone-like touch capabilities for release early next year. Microsoft has been secretive about its plans for a tablet, but a video making the rounds of the blogosphere shows a dual-LCD-screen prototype that closes like a book."E-readers are a transitional technology," says Rotman Epps of Forrester Research. It means that just as the e-reader is taking off, it may be becoming obsolete.