When the Japanese yen recently hit its weakest level against the U.S. dollar in about 40 years, it wasn’t just a problem for the government in Tokyo. It was also a problem for the United States. 近期，日元兑美元汇率跌至约40年来的最低水平，这不仅是东京政府的麻烦，也是美国的麻烦。 The U.S. Treasury…