B篇倒數第二段的倒數第二行The life expectancy of Japanese women has shot up to almost 85, the highest in the world.倒數第一段At the same time, extended families are being replaced by nuclear families.什么叫"extended families "，什么叫"nuclear families"?D,E兩篇完全沒有看懂，能否把大意說一下？
熱心網友
nuclear families 指沒有 grandparents 的家庭 其他的字典里有