5月8日，某套期保值者以2270元／吨在9月份玉米期货合约上建仓，此时玉米现货市场价格为2100元／吨，则此时玉米基差为（　）元／吨。

     The picnics，speeches，and parades of today’s Labor Day were all part of the first celebration，held in New York City in 1882. Its promoter was an Irish-American labor leader named Peter J. McGuire, a carpenter by trade. McGuire had worked since the age of eleven and in 1882 was president of the United Brotherhood of Carpenters and Joiners(UBCJ). Approaching the City’s Central Labor Union that summer，he proposed a holiday that would applaud(赞许)“the industrial spirit-the great vital force of every nation”. on September 5，his suggestion bore fruit，as an estimated 10，000 workers，many of them ignoring their bosses’warnings，left work to march from Union square up Fifth Avenue to 42nd Street. The event gained national attention，and by 1893 thirty states had made Labor Day an annual holiday. 
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/     The quick adoption of the scheme may have indicated less about the state lawmaker’s respect for working people than about a fear of risking their anger. In the 1880s the United States was a land sharply divided between the immensely wealthy and the very poor. Henry George was accurate in describing the era as one of“progress and poverty”. In a society in which factory owners rode in private Pullmans while ten-year-olds slaved in the mines，strong anti-capitalist feelings ran high. Demands for fundamental change were common throughout the labor press. With socialists demanding an end to“wage slavery" and anarchists(无政府主义)singing the praises of the virtues of dynamite(炸药)，middle-of-the-roader slike Samuel Gompers and McGuire seemed attractively mild by comparison. One can imagine practical capitalists seeing Labor Day as a bargain：A one-day party certainly cost them less than paying their workers decent wages. 

假定年利率为8%，年指数股息率d为1．5%，6月30 E1是6月指数期货合约的交割日。4月15 日的现货指数为1 450点，则4月15 E1的指数期货理论价格是（ ）点。

    A theme is emerging from the flood of recent corporate earnings reports: cost cuts are boosting profits. Investors are cheering, but they shouldn't. Even in these tough times, more CEOs should be talking about how they are seeking out investments, developing new technologies and making acquisitions.
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/That's what will set their companies up fora stronger future. Intel Corp.'s former CEO Gordon Moore had it when he said years ago that "you can't save your way out of a recession." He meant that even in the toughest times, companies have to spend money on new ideas.Recessions always end, Moore often said, and when they do, companies that embraced innovation (创新)during the downturn won't be stuck with obsolete products and services. Instead, they'll have new things to offer' once demand picks up again.
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/    "Customers don't come out of recessions spending the way they did before," said Chunka Mui, who has studied how companies can capitalise on opportunities during crises at his Chicago-based consulting firm, The Devil's Advocate Group. "They demand something different."
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/    Surprisingly few companies are following Moore's advice of innovating during recessions. Many have been weakened by the pullback in consumer and business spending as well as tight credit conditions,which is making it harder for companies to get loans to fund their operations. That's driven some to hold cash and make drastic cost cuts. They're slashing (大幅度削减)jobs and wages and closing stores and factories.
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/    The aggressive cuts have allowed companies to exceed Wall Street's expectations for their earnings. In fact, the"good" news has sent the Dow Jones industrial average above 10,000 for the first time in a year. The problem is that too many companies are making widespread, not focused cuts. They're telling every division to cut 10 percent of their work force or slashing marketing dollars by the same amount companywide.
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/    "That is a quick way to rid a company of costs. But it doesn't help it get in a better position going forward",says Cesare Mainardi, managing director at the consulting firm Booz & Co.and coauthor of the new book Cut Costs, Grow Stronger, "and a downturn like this should force people's hand".

    Single-sex education is the practice of conducting education where male and female students attend separate classes in separate schools. The practice was predominant (突出的) before the midtwentieth century, particularly in secondary education and higher education. Single-sex education is often advocated on the basis of tradition,as well as religious or cultural values. It is practiced in many parts of the world.
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/    A number of studies starting in the 1990s are showing statistical data that children from single-sex schools are outperforming students from coeducational (男女同校的) schools,although some studies also say that these are non-conclusive. In 2002, because of these studies and bipartisan (两党的) support, the US law of 1972 that made coeducation in public schools mandatory was revoked and funding was given in support of the single-sex option. There are now associations of parents who are advocating for single-sex education.
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/In some cases, parents are now making the decision to send their child to a single-sex schools for the following reasons.The first one is the teacher-student ratios are typically much higher in the single-sex schools because in most single-sex schools there are smaller class sizes. Secondly, parents and students are often choosing a single-sex learning environment because they think with good reason that their child or themselves will receive a better education. International research has shown that boys and girls perform best when they are taught separately in their teen years.
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/    Critics of the single-sex education argue that segregated learning facilities are inherently unequal. System bias will reinforce gender stereotypes and perpetuate societal inequalities in opportunities afforded to males and females. Single-sex schools in fact accentuate (使……突出) gender-based educational limitations and discrimination. Boy's schools may not offer home economics classes, while girl's schools may not offer metalwork, woodwork or as wide a variety of sports.
style=color: rgb(51, 51, 51); font-family: "Microsoft YaHei"; white-space: normal; background-color: rgb(250, 250, 250);/    Some children like larger classrooms. These larger classrooms give them more competition and can even make some students more motivated to work harder. When there are more children in a class people may think children can get lost, but some students think of it as something that pushes them to work harder. Although this statement is the opposite of a single-sex school advantage that was listed above, this is just further proof that it all depends on each child and that each children quires a learning environment best for her/him.

假设某投资者持有A、B、C三只股票。三只股票的β系数分别为1．2、0．9和1．05，其资金分配分别是100万元、200万元和300万元，则该股票组合的β系数为（ ）。

基差变小，称为走弱（Weaker)。基差走弱常见的情形有（）