单选题 It's often hard to see your mistakes as you're making them. "Yikes! The kids are moving back in!" Thus goes the moan of the baby boom generation, around 2007. But letting the kids move back in is not the social error we're talking about. Instead, the big mistake is the loudly voiced annoyance of the boomers. Most mistakenly decry the notion of the boomerang generation. For example, the authors of a recent book on the topic, Morn, Can 1 Move Back In With You? report, "The parents of the 39 million twenty-somethings in the United States face the unprecedented challenge of their children's prolonged adolescence. " The subtitle of the book is even more revealing: "A survival guide for parents of twenty-somethings. "
In order to fully appreciate the depth of the error being made here, we all need to step back a bit and look at the bigger picture. This epidemic of kids moving back home is first not "unprecedented," and second, it's not a bad thing. The precedent for this trend can be found among the other 6.2 billion non-Americans on the planet, many of whom happily live with their adult children, often in three-generation households. Finally, the agrarian history of this country before World War II allowed kids to live and work around the farm well into adulthood.
Adult kids moving back home is merely the most noticeable symptom of a larger, fundamental transformation of American society. We are nationally beginning to recognize the costs of the independence the so-called greatest generation imposed on us. Kids in their generation went off to World War II and grew up on the bloody beaches of distant lands. After the war, the survivors had factories to build and the wealth to buy their white-picket-fence dreams out West. They designed a social and fiscal system that has served their retirement years very well. But their historically unique retirement system mistakenly celebrated independence and ignored the natural state of human beings -that is, interdependence. Moreover, their system breaks down with the onslaught of their kids' retirement.
Regarding boomerang kids, most demographers focus on the immediate explanations for the changes, such as the growing immigrant population, housing shortages and high prices, and out-of-wedlock childbearing. Many psychologists have noted that baby-boomer parents enjoy closer relationships with their fewer children that allow extended cohabitation. However, all these explanations are simply symptoms of the larger, more fundamental reuniting of Americans into households.
The rate at which our American culture is adapting will accelerate as baby boomers begin retiring. Creative housing arrangements are necessitating and allowing three generations to live together again. But such multigenerational households don't make sense for everyone. The culture itself frequently gets in the way, reinforcing the perception of a stigma attaching to lack of independence. Despite these problems, once you begin talking with your friends about three-generation households, you will begin hearing stories about how such obstacles are being overcome.

【正确答案】 A

【答案解析】[题眼] 因果关系处设题
[解析] 事实细节题。文童第三段首句指出成年子女回巢是表明美国社会正发生根本变化的最引人注目的现象，那么该现象的原因是什么呢？紧接着作者给出分析。从强调独立精神到重视人类相互依赖的天性，可以看出美国的文化正发生变化。末段首句指出美国文化正在加快调整速度，随后指出三代同堂的复兴，验证了答案为[A]。文章第二段末提到美国在二战前是个农业国，当时的父母愿意让子女同住与现在子女回巢不是出于相同的原因，排除[B]；第四段人口学家提到的那些具体困难是子女回巢的直接原因，而非根本原因，排除[C]；[D]“家庭养老保障制度”文章没有提及。