求助PREP 07 SC 32

笨熊1028

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

本题为啥选择E？现在完成时可以和现在时连用？

wildbean

可以的，因为是两个不同的动作，一个动作表示一般的状况，一个表示从过去开始一直持续到现在

笨熊1028

可以的，因为是两个不同的动作，一个动作表示一般的状况，一个表示从过去开始一直持续到现在

-- by 会员 wildbean (2011/11/6 23:15:01)

A为啥不对？难道是having been?by constrcting不是比by construstion of 简洁吗？

aaroncheng

n + having done  不可以当做限定性修饰    ABCD 很好排除 ，但是疑问是E中 后面的动作已经用现在完成时了，说明动作已经完成， 怎么能用ving伴随？ 难道是因为originally 的作用？

根儿哥1989

E中的originally 应该是过去时的标志啊，为什么用flowing呢？