OG92, at once

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（D）

(E) so many changes at once that confronted them in

请路过的人帮忙看一下，这句中at once怎么解释？为什么不能改变位置？

taxpayers had Never before confronted

as many changes at once as

they confronted in the Tax Reform Act of 1986

taxpayers从来没有立即遇到如此多的变化（意思里还是和以前的某个时期相比，以前也是在发身某件时候立即就遇到了变化），这种变化的数量和在taxpayers遇到1986年税制改革的时候一样多

改变位置taxpayers had Never before confronted at once as many changes as 似乎句子结构并不合理

confronted是及物的应该直接+名词

嗯！明白了！

谢谢！！！

"at once" has 2 meanings:
1. immediately,
2. at the same time

I think in this sentence, it means "at the same time" to modify the "many changes" confronted by the tax payer. An example: I can't do two things at once!

【 at the same time 】sounds better，but it's not the point of this sentence ,no matter it means immediately or at the same time,both of them can be explained in chinese,but in my opinion,immediately is the key which does not change the logic meaning of this sentence.

[at the same time] is a good expalanation,but somehow ,it change the accentuated components of the sentence.[as many as ]is the component which was accentuated by author.

Anyway ,you give me some hits about this pharse,and what a good job it is !thank you

But I do have a separate question here: why "as many as" not "so many as" considering that "Never" is negative?
Does "so many as" have to be used after an explicit "not"?

NN help!

"so many as"is such a pharse that can be use in GMAT within negative tense.[Never] is a negative adv.But "so....as" only can be used when there is "no/not"in the sentence in Gmat.Negative adv,like "never" can not  replace "not" in Gmat.It's a positive sentence in negative meaning.what we need is a negative sentence which has "not" in the sentence.Just remember it ,it always help.

my two cents:    not negative  but  negative structures.

1.  After not, we can use so...as... instead of as...as....  This structure is more common than less than  in informal Egnlish.

He's not as/so successful as  his sister.

2.  We can use as much/many ...as... to talk about quantity.

I haven't got as much  money as  I thought.

We need as many  people as  possible.

2-1.  As much/many  can be used as pronouns, without following nouns.

I ate as much  as I could.

She didnt' catch as many  as she'd hoped.

2-2.  And as much ... can be used as an adverb

You ought to rest as much  as possbile.

negative structures

exactly

more clear than me

ALL GENERALIZED,IF YOU FIND [NOT] IN THE SENTENCE ,[SO...AS] NOW CAN BE USED.AND vice versa