这是表示倍数的一般结构
once as much/many as
twice as much/ many as
three times as much/many as
表示是……的几倍
cotton是不可数,所以用twice as much as
然后,名词一般放在much后面,就是twice as much cotton as……
最后就是再加上时间这类的状语,就变成 twice as much cotton this year as, 感觉上把很多成分都加在后面一个as 之前,倍数+as……+as……