再来一道语法？？？

traviszhu

32. (26170-!-item-!-188;#058&003042)
The Chicago and Calumet Rivers originally flowed into the St. Lawrence by way of Lake Michigan,
but having been redirected by constructing canals so that the water now empties into the
Mississippi by way of the Illinois River.

(A) Rivers originally flowed into the St. Lawrence by way of Lake Michigan, but having been
redirected by constructing
(B) Rivers had originally flowed into the St. Lawrence by way of Lake Michigan, but they have been redirected by constructing
(C) Rivers, which originally flowed into the St. Lawrence by way of Lake Michigan but have been
redirected by the construction of
(D) Rivers, originally flowing into the St. Lawrence by way of Lake Michigan, but having been
redirected by the construction of
(E) Rivers, originally flowing into the St. Lawrence by way of Lake Michigan, have been redirected through the construction of
这道题里的originally出现不是应该用过去时吗？为什么选E？帮忙解释下

crystalhuang

用过去式没错，这是省略，句子逻辑主语与主句一致时，可以省略
由这个The Chicago and Calumet Rivers, which originally flew into the St. Lawrence by way of Lake Michigan演变过来

traviszhu

用过去式没错，这是省略，句子逻辑主语与主句一致时，可以省略
由这个The Chicago and Calumet Rivers, which originally flew into the St. Lawrence by way of Lake Michigan演变过来

-- by 会员 crystalhuang (2010/4/24 16:19:57)

省略？省去了什么？还有 which originally flew into the St. Lawrence by way of Lake Michigan演变到了 originally flewing into the St. Lawrence by way of Lake Michigan？

crystalhuang

不是逻辑主语，晕了，今天……
originally flowing into the St. Lawrence by way of Lake Michigan作定语，修饰的是The Chicago and Calumet Rivers
如果用过去式就有两个谓语动词了

PurpleSun520

******供参考*********
通读一下，大致意思是说C&C河本来是流进ST. 但是被重新引导导致河水现在流入M.
A:but having been.... 前面没有内容与之对应-->排除
B:没有明显结构语法错误-->待定
C:the Chicago and calumet rivers, which..... 只有主语-->排除
D:错误与C相同-->排除
E:没有明显结构语法错误-->待定
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比较B和E：
1. they have been redirected by constrcting
VS.
C and C have been redirected through the construction of

"....by constracting" means that the rivers themselves constrcuted the canals.(河流本身怎么建造自己呢？)-->incorrect
2. in order to use past perfect, the sentence must also contain either a verb in the simple past tense or a time marker that occurred in the past but later than the past perfect action
however, no simple past tense verb or a time marke exists here.
-->eliminate B