请教同位语和独立主格的问题

CRX1230

  For almost a hundred years after having its beginning in 1788, England exiled some 160,000 criminals to Australia.

(A) For almost a hundred years after having its beginning in 1788,

(B) Beginning in 1788 for a period of a hundred years,

(C) Beginning a period of almost a hundred years, in 1788,

(D) During a hundred years, a period beginning in 1788,

(E) Over a period of a hundred years beginning in 1788,

选E

这里D，a period..是同位语还是独立主格啊？ 我在新东方上的时候老师的解题思路是同位语没有sth doing型式，所以这个是独立主格，起到补充说明作用，可以省略先不看，那么D选项只有一个时间段，不能构成后面一般过去时exlied的使用


但是我看了网上的一些解释，又说a period是同位语..将a hundred years解释成a period beginning in 1788意思不对，所以排除

到底哪个准确？

另外不论独立主格也好，同位语也好，判断出来了怎么用来解题？我能不能通过省略不看来排除选项，就像我第一个解释的过程一样。

暴躁的大叔

好问题！ 独立主格和同位语有时候真的很难分清楚

比如这道题：
The computer company has announced that it will purchase the color-printing division of a rival
company for $950 million, which is part of a deal that will make it the largest manufacturer in the
office color-printing market.

(A) million, which is part of a deal that will make
(B) million, a part of a deal that makes
(C) million, part of a deal making
(D) million as a part of a deal to make
(E) million as part of a deal that will make

http://www.manhattangmat.com/forums/the-computer-company-has-announced-that-it-will-purchase-the-t2673.html

Ron说独立主格一般来说那个noun都是抽象名词引导的。B和C都是同位语。

我认为D选项 a period应该是同位语，而不是独立主格，独立主格不是修饰名词，而是修饰主句的，独立主格可以在主句前也可以在主句后，所以D选项中做独立主格的话，那么修饰无能。