在过去的几十年里，美国的中产阶级家庭曾经依靠努力工作和公平竞争来保证自己的财务安全，但现在的经济风险和新出现的情况已经改变了这种状况。

During the past generation, the American middle-class family that once could count on hard work and fair play to keep itself financially secure has been transformed by economic risk and new realities.

youdao

许多电热联合系统计划曾经受到能源计划和过去的市场条件的支离破碎的方法的阻碍。

Many CHP projects have been hindered by a fragmented approach to energy planning and past market conditions.

youdao

他过去曾经认为，基因和大脑功能，就可以决定我们的一切。

He once believed that genes and brain function could determine everything about us.

youdao

Royal Shell used to have Dutch shares that traded in Holland and U.K. shares traded in London.

壳牌公司过去就曾经同时拥有在荷兰交易的荷兰股份,和在伦敦进行交易的英国股份。

耶鲁公开课 - 金融市场课程节选

The interesting thing is that through time, as political winds change, these taxes have changed and they've gone up to some very high levels in the past in the United States and other countries.

有趣的是在不同时期,如果政策方向有所转变,税率也会改变,在过去的美国和其他国家,税率曾经相当高

耶鲁公开课 - 金融市场课程节选