Their marriages remained intact to a greater extent than did those of couples who married in earlier as well as later decades.

这句话出自2003年专八真题改错，原题为：

（为了方便了解语境，我已将原题中其他的错误改正过来,只剩下与该句相关的一个错误。）

  Demographic indicators show that Americans in the postwar period were more eager than ever to establish families. They quickly brought down the age at marriage for both men and women and brought the birth rate to a twentieth century high after more than a hundred years of steady decline, producing the “baby boom.” These young adults established a trend of early marriage and relatively large families that went on for more than two decades and caused a major but temporary reversal of long-term demographic patterns. From the 1940S through the early 1960s, Americans married at a higher rate and at a younger age than their European counterparts.

  Less noted but equally significant, the men and women who formed families between 1940 and 1960 also reduced the divorce rate after a postwar peak; their marriages remained intact to a greater extent than did that of couples who married in earlier as well as later decades. Since the United States maintained its dubious distinction of having the highest divorce rate in the world, the temporary decline in divorce did not occur to the same extent in Europe. Contrary to fears of the experts, the role of breadwinner and homemaker was not abandoned.

疑问：1.上次提了一个关于比较句的问题，“语法探讨”老师回答“按照Huddleston CGEL的解释，主句的比较项的对应项在比较分句中作主语，则这个主语必须省略，主语的位置形成一个空缺（gap). 即than从句是一个缺少主语的不完整的分句。”

（链接：http://ask.yygrammar.com/q-26113.html）

不知这个解释可否适用于本句话的理解。我对这句话的改法是“去掉that”，即：

Their marriages remained intact to a greater extent than did of couples who married in earlier as well as later decades.

此时，从句中的主语（比较项的对应项the marriages）省略，“of couples who married in earlier as well as later decades”修饰被省略的主语the marriages，即the marriages of couple who married in ...，且谓语did提前，形成完全倒装。不知道我这个想法错在哪里，还望老师赐教。

2. 答案是将that改为those，即：Their marriages remained intact to a greater extent than did those of couples who married in earlier as well as later decades.我的疑惑是，如果此处用those,直接“... to a greater extent than did those who married in earlier as well as later decades.”，去掉“of couples”不是更加简洁明了吗？可以这样子改吗？