学员疑问： 老师，下面这个句子的on which to base future prosperity怎么理解呢？

At a time when many states will struggle with labor shortages because of modest population growth, Arizona has a priceless chance to build a populous, hardworking and skilled workforce on which to base future prosperity.  

老师解答：on which to base future prosperity是一个紧缩的定语从句修饰workforce，完整的表达为a workface on which Arizona can base future prosperity。句意：在许多州因人口增长缓慢而面临劳动力短缺的时候，亚利桑那州却拥有一个宝贵的机会，可以建立一支为未来的繁荣打下基础的人口众多、工作努力、技能娴熟的劳动力队伍。

点评分析： 有时候，由于表达的需求，可能会使用省略的形式表达句意。