求解两个恼人的语法问题。。谢谢！

以下两道是OG SC里摘出来的句子。都是正确答案。但是我很难理解。请各位帮忙看看。

1.According to surveys by the National Institute on Drug Abuse, about 20 percent of young adults used cocaine in 1979, twice the number reported in the 1977 survey.

TWICE只有副词词性。如果是如此，在GMAT文法要求如此严谨的前提下，怎么解构最后一个分句？

2.Judge Bonham denied a motion to allow members of the jury to go home at the end of each day rather than be confined to a hotel.

RATHER THAN前后对称，沈略TO。所以TO GO HOME和TO BE CONFINED TO A HOTEL同是ALLOW发出的动作。那么，就成了 允许 某人 被困在HOTEL里。解释是不是很不通？

这里其实是一个 twice 的省略结构

twice as much as

根据 Longman

twice as many/much (as something) They employ 90 people, twice as many as last year.

twice as high/big/large etc (as something) Interest rates are twice as high as those of our competitors.

twice the size/number/rate/amount
        etc an area twice the size of Britain

太好了。谢谢！