英语翻译

英语翻译
1.But these nations continue to carry a lot of debt compared to the size of their econoies.
compare to 不是应该是相似吗 翻译怎么是：但这些国家仍然背负着与其经济规模不相称的巨额债务
为什么是不相称?
2.Europe's two leading central banks are cutting key interest rates in an effort to ease the impact of the global financial crisis.
那个cutting key interest rates
3.Four out of five online adults use social media at least once a month
Four out of ,怎么可以这样弄