求翻译：就我所知，从2009年12月开始，美国三大评级机构从希腊开始，接着下调葡萄牙、西班牙等欧元区国家的评级。一时间，欧元一蹶不振，大幅下滑，而美元则高歌猛进，美国国债价值蒸蒸日上。希腊债务危机升级为欧洲主权债务危机，而美国在其中成了大赢家。是什么意思？

I know, from December 2009, the U.S. began the three major rating agencies from Greece, then down Portugal, Spain and other countries in the euro zone rating. For a time, the euro tumbled sharply, and the dollar surging, the value of U.S. Treasury bonds flourishing. Greek debt crisis for the Europea

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I know, starts from December, 2009, the American three big rating organizations start from Greece, then declines Euro sector country and so on the Portugal, Spain rating.Suddenly, a euro helplessness, glides down largely, but US dollar advances triumphantly, the American national debt value progress

As far as I know, starting from December 2009, United States of three rating agencies from Greece began, then downgraded Portugal, and Spain eurozone countries, such as a rating. Time, the euro collapsed, plunging, while the dollar March, United States Treasury value increase. Greece debt crisis esc