求助OG76

76Never before had taxpayers confronted so many changes at once as they had in theTexReform 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

我选的是A,正确答案是 D.这不是否定句吗,为什么不选A呢?

as.......as.....

not so.........as.....

这两个是习语