该问题从2010年5月开始凸显，当时欧洲央行出手承担了购买某些国家政府债券的责任，不然这些国家的长期利率就将大幅增加。
This became apparent in May 2010, when the ECB assumed the responsibility of purchasing the government bonds of countries that otherwise would have experienced substantial increases in long-term interest rates.