(A) have migrated to the Western Hemisphere over a
bridge of land that once existed
(B) were migrating to the Western Hemisphere over a
bridge of land that existed once
(C) migrated over a bridge of land to the Western
Hemisphere that once existed
(D) migrated to the Western Hemisphere over a bridge of
land that once existed
(E) were migrating to the Western Hemisphere over a
bridge of land existing once

今天複習時發現沒注意到的地方
og說
[highlight=]existing once in E is imprecise[/highlight]
我個人推測
根據莫老師的解法
形容詞子句時態若早於主要子句時
那不能改成分詞片語
請教各位
不知道我的理解有沒有錯??