The Great Recession and its surge of long-term unemployment are a severe test of what was once seen as a distinctive US economic strength.
大萧条以及美国长期失业率飙升，是对曾被视为美国经济独特优势的严峻考验。
2
Based on it, the formulae of contact strength of mesh points between the movable teeth and the surge wheel, the movable teeth and the internal gear are derived.
在此基础上导出了活齿与激波器、活齿与内齿轮啮合处的接触强度的公式；
3
A weak pound could also explain Britain's renewed economic strength, much as a surge in the yen has increased worries about Japan.