During the past generation, the American middle-class family that once could count on hard work and fair play to keep itself finacially secure has been transformed by economic risk and new realities.
句子主干：
主语：he American middle-class family
主语的定语从句：that once…
谓语：has been …
宾语：economic risk and new realities
状语：During…
在过去的一代人中，那些依靠辛苦工作和公平竞争来维持自身经济保障的美国中产阶级家庭已经逐渐的被经济风险和新的现状所改变。
during the past generation
过去的一代人
但更多的翻译是 过去的二三十年
count on
= depend on 依靠
be transformed by
别…所改变
Transformer 变形金刚
