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工资与就业之间的关系并不像某些模型所暗示的那样简单。
The relationship between wages and employment is not as straightforward as some models suggest.
在观察性研究中,我们常常不得不依赖于无法直接检验的假设。
Sometimes it seems as if there are more solutions than problems. On closer scrutiny, it turns out that many of today's problems are a result of yesterday's solutions.