请教！gmat 旧prep的两道语法题

放下那个鸡腿

Unlike many United States cities, where a river is no longer the focal point of urban life, the river in San Antonio winds through the middle of the business district, and the River Walk, or Paseo del Rio, is the city's most popular attraction.
(A) Unlike many United States cities, where a river is no longer the focal point of urban life, the river in San Antonio
(B) Unlike the river in many cities in the United States, which is no longer the focal point of urban life, in San Antonio the river
(C) Today the river in many cities in the United States is no longer the focal point of urban life, unlike San Antonio, where it
(D) In few United States cities today, a river is the focal point of urban life, but the river in San Antonio
(E) No longer do many cities in the United States have a river as the focal point of urban life, but in San Antonio the river

这道题答案选E，虽然可以把其它选项都排除掉，但是E选项的倒装还原之后还是怪怪的。可以帮忙写一下E选项倒装还原之后是怎样的吗？

There is a widespread belief in the United States and Western Europe that young people have a smaller commitment to work and a career than their parents and grandparents and that the source of the change lies in the collapse of the "work ethic."
(A) a smaller commitment to work and a career than their parents and grandparents
(B) less of a commitment to work and a career than their parents and grandparents
(C) a smaller commitment to work and a career than that of their parents and grandparents
(D) less of a commitment to work and a career than their parents and grandparents had
(E) a lessening of the commitment to work and a career that their parents and grandparents had

这道题为什么后面要加had，就算要加不应该加do才对吗？had难道不是表达完成时的吗？

请NN们帮忙解决，谢谢！！

VincentFSJ

No longer do many cities in the United States have a river as the focal point of urban life, but in San Antonio the river
many cities in the united states no longer have a river as the focal point of urban life,/many cities in the united states don't have a river as the focal point of urban life any longer
had和have平行，你哪里看到了是完成时态，我觉得这个had暗示了省略了when they were young people,不然就理解成了现在的年轻人和他们的父辈现在的比较

放下那个鸡腿

VincentFSJ 发表于 2016-9-18 14:59
No longer do many cities in the United States have a river as the focal point of urban life, but in  ...

噢噢！突然间就明白了！谢谢啦=3=