请教 PP T1-4

jarson2000

请教大虾一个语法：

pp
test_1

4. perhaps the most significant postwar trend was the
  decentralization of cities throughout the united states,
  _________ when massive highway-building programs
  permitted greater suburban growth.

       and accelerated a phenomenon  
       a phenomenon that accelerated  
       accelerating a phenomenon which,  
       the acceleration of which phenomenon

有以前解释如下：

toefl_2003MM的解答：
4. （perhaps ）（the most significant postwar ）trend was the
  decentralization （of cities throughout the united states,）
a phenomenon（ that accelerated）  （when massive highway-building programs
  permitted greater suburban growth.）这样句子成分清晰了吧！

我搞不清that accelerated 如何修饰a phenomenon。 个人认为如that accelerated 是同位语从句，觉得缺少主语。如是定语从句觉得缺少系动词。, 恳请指点。

[此贴子已经被作者于2004-4-14 1:24:55编辑过]

xkfy0521

同位语a phenomenon 对前面现象的补充说明，而同位语从句中又有定语从句that引导。