[求助]主语比较和状语比较的区别

在看crowkiller大牛的《比较结构总结》时有一些疑问：是关于主语比较和状语比较的分类，下面的两个主语比较和一个状语比较的例子我很难看出区别，请大家帮忙看看如何区分：

http://forum.chasedream.com/dispbbs.asp?BoardID=23&ID=263606&replyID=&skin=1

主语比较_主谓宾_as+adj.+宾语+as

168. Today, because of improvements in agricultural technology, the same amount of acreage produces double the apples that it has in 1910.

(A) double the apples that it has

(B) twice as many apples as it did

(C) as much as twice the apples it has

(D) two times as many apples as there were

(E) a doubling of the apples that it did

主语比较_主谓宾_as+adj.+不定式宾语+as

265. Thomas Eakins' powerful style and his choices of subject--the advances in modern surgery, the discipline of sport, the strains of individuals in tension with society or even with themselves--was as disturbing to his own time as it is compelling for ours.

(A) was as disturbing to his own time as it is

(B) were as disturbing to his own time as they are

(C) has been as disturbing in his own time as they are

(D) had been as disturbing in his own time as it was

(E) have been as disturbing in his own time as

状语比较_主谓宾_完整句_as+adj.+宾语+as
92. Never before had taxpayers confronted so many changes at once as they had in the Tax Reform Act of 1986.
(A) so many changes at once as they had in
(B) at once as many changes as
(C) at once as many changes that there were with
(D) as many changes at once as they confronted in
(E) so many changes at once that confronted them in

这3个比较都是一前一后或两个不同时间的比较

为什么把前两个看成主语比较；第3个看成状语比较