[讨论]PREP SC 169-75

amorela

怎么也没找到PREP SC 169道题目的那套中,第75条的讨论,所以请大NN们帮忙看一看:

Beneath the soil of the Malheur National Forest in eastern Oregon, a fungus has for centuries been slowly weaving its way through the roots of trees, to become the largest living single organism known to humans.

 

(A) has for centuries been slowly weaving its way through the roots of trees, to become

(B) has slowly woven its way through the roots of trees for centuries, and so becoming

(C) that has been slowly weaving its way through the roots of trees for centuries has become

(D) that has for centuries slowly woven its way through the roots of trees and has become

(E) that, having slowly woven its way through the roots of trees for centuries, to become

这里C的has been weaving,我不理解为什么要用完成进行时?

谢谢!

neo1001

表示动作从过去开始，一直延续到现在

如果只用过去式或完成式，表示动作发生在过去，但并没有延续到现在的意思