请教两道白勇语法全解中的题

popo2

p212 43题

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

不选A的解释是：so...as只能用在否定句中。

但是我看到有never不能代表否定句吗？

p209  36题

In the 1980's the rate of increase of the minority population of the United States was nearly twice as fast as the 1970's.

C. twice what it was in

what 代表的是什么？it was 和what什么关系？

如果原题中没有twice，这句话：

In the 1980's the rate of increase of the minority population of the United States was nearly as fast as it was in the 1970's. 对吗?

多谢！

leowz

第一题，好像是固定用法，只能not so。。。as，其他不行

第二题，我也说不清楚，为了构成比较的平行，只能这样吧，具体什么道理，由于语法知识薄弱，不懂，一般我处理这种问题就是背下来，呵呵

popo2

多谢楼上了