(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
正確答案：E
選錯了A
我的思路如下：
(A) but having been .... 省略主詞, 好像很好啊, 不知錯在哪？!
(B) but they 的『they』不會很累贅嗎？重複前面的 rivers?
(C) 沒有動詞
(D) rivers but 結構不對
請高手大牛們解惑
