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题库 / Prep2007E2-SC-32
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.
Rivers originally flowed into the St. Lawrence by way of Lake Michigan, but having been redirected by constructing
Rivers had originally flowed into the St. Lawrence by way of Lake Michigan, but they have been redirected by constructing
Rivers, which originally flowed into the St. Lawrence by way of Lake Michigan but have been redirected by the construction of
Rivers, originally flowing into the St. Lawrence by way of Lake Michigan, but having been redirected by the construction of
Rivers, originally flowing into the St. Lawrence by way of Lake Michigan, have been redirected through the construction of
B，没有过去的动作和时间来支持had；河之前咋流，现在转向了，这也没啥好转折的。
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