分词短语修饰和that从句修饰的区别

杀鸡给猴看

对于用分词短语修饰和that从句修饰的区别还是不明白，
30． Freedman's survey showed that people living in small towns and rural areas consider themselves no happier than do people living in big cities.
（A） no happier than do people living
（B） not any happier than do people living
（C） not any happier than do people who live
（D） no happier than are people who are living
（E） not as happy as are people who live
为什么这个地方可以用living in big cities.到底什么时候用分词短语修饰，什么时候用that从句修饰？
又如OG80题：
80. Salt deposits and moisture threaten to destroy the Mohenjo-Daro excavation in Pakistan, the site of an ancient civilization that flourished at the same time as the civilizations in the Nile delta and the river valleys of the Tigris and Euphrates.
(A) that flourished at the same time as the civilizations
(B) that had flourished at the same time as had the civilizations
(C) that flourished at the same time those had
(D) flourishing at the same time as those did
(E) flourishing at the same time as those were
Choice A, the best answer, uses the simple past tense flourished to describe civilizations existing simultaneously in the past. Choice B wrongly uses the past perfect had flourished; past perfect tense indicates action that was completed prior to some other event described in the simple past tense: for example, "Mayan civilization had ceased to exist by the time Europeans first reached the Americas." Choice C lacks as after time. In choices C, D, and E, the plural pronoun those has no plural noun to which it can refer. In C, had signals the incorrect past perfect; did in D and were in E are awkward and unnecessary(没有歧义的时候补出动词多余，尤其在这儿，因为后边还有一堆介词短语，就更加显的笨拙，而且造成歧义). D and E also incorrectly use the present participle flourishing where that flourished is needed.
这里菜鸟GG说，尽量要把比较放在从句中进行，而不要放在分词结构中进行，但是我对于这个规律表示怀疑，为什么会是这样，还是象白勇老师说的一样，要优先that从句？
困惑中！请各位NN们赐教！

joe11

30. You can't use that-clause here.  than people WHO ARE living in the city.

    To be concise, you get ride of "WHO ARE" and just leave the "living in the city".

80.菜鸟GG说，尽量要把比较放在从句中进行，而不要放在分词结构中进行

   That's correct. Think about it, that-clause can introduce a complete sentence, but -ing cannot.

二狼神

joe的解释好!