extending the issue of the two-parent versus one-parent family is, "To what extent are these notions validated " cross-culturally?"

将双亲和单亲家庭的问题扩展了一下，“这些概念究竟在多大程度上,会因跨文化差异而有所变化“

耶鲁公开课 - 心理学导论课程节选

If the average age of death was something like forty-five, maybe a fifty-fifty chance of--high risk-- of one of the parents dying.

那么这个概率其实很低,不是吗,大概有高达50%的可能性,双亲中的一人会死去

耶鲁公开课 - 金融市场课程节选

Back in the 1840s, life insurance was very important because the average expectancy of life was only something like forty-five years, so that meant parents were dying left and right.

在19世纪40年代的时候,寿险是非常重要的,因为当时的人均期望寿命,仅为45岁左右,这意味着双亲平均只能活到45岁

耶鲁公开课 - 金融市场课程节选