请问一道语法题

giveall

  Never before had taxpayers confronted as many changes at once as they confronted in the Tax Reform Act of 1986.

为什么不能选at once as many changes as?（答案就是原话）我觉得的这样比原话更简练啊，不就是说交税者原来没有遇到过1986年那么大的变化吗？

KennyChenzju

change和Tax Reform Act不是并列结构。原话是as many chages at once as (the change) they confronted in the Tax Reform Act

dianecarton

at once位置不对，as as结构比较对象不成立