下列关于套利的说法，正确的是( )。
A．考虑了交易成本后，正向套利的理论价格下移，成为无套利区间的下界
B．考虑了交易成本后，反向套利的理论价格上移，成为无套利区间的上界
C．当实际的期指高于无套利区间的上界时，正向套利才能获利
D．当实际的期指低于无套利区间的上界时，正向套利才能获利
参考答案：C
解析： 无套利区间，是指考虑交易成本后，将期指理论价格分别向上移和向下移所形成的一个区间。具体而言，若将期指理论价格上移一个交易成本之后的价位称为无套利区间的上界，将期指理论价格下移一个交易成本之后的价位称为无套利区间的下界。只有当实际的期指高于无套利区间的上界时，正向套利才能获利；反之，只有当实际期指低于无套利区间的下界时，反向套利才能获利。
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| Bill Gates is head of the software company Microsoft and one of the world's richest men. He was born on October 28, 1955 and grew up in Seattle with his two sisters. He was a very bright boy. Science and math were his two favorite subjects at school. And he dreamed of being a scientist. Bill first started to play on computers at the age of 13. At that time, a computer was a very large machine. Once he was interested in a very old computer. He and some of his friends spent as much time as possible on computers. In the end, they worked out a software program. Bill sold it for 4,200 dollars when he was only 17. In 1973, Bill went to Harvard University. In 1975, Bill and his partners developed a software program called BASIC. This was not the first program ever created, but its inventors were the first to decide that people who wanted to use it should pay for it. BASIC was a success. Then Bill left Harvard to work for Microsoft, a company he started in 1975 with his boyhood friend Paul Allen. They thought the computer would come into every office and every home soon. So they began developing software for personal computers. They improved the software to make it easier for people to use computers. After many years of hard work, Microsoft becomes one of the most successful companies. And Bill Gates also becomes one of the richest businessmen in the world. | |
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