The number of people flying first class on domestic flights rose sharply in 1990, doubling the increase of the previous year.
A. doubling the increase of
B. doubling that of the increase in
C. double as much as the increase of
D. twice as many as the increase in
E. twice as many as the increase of
题目释义： The number… rose sharply…, doubling the increase of…
考点：
1.伴随状语：doing引导伴随状语或者目的状语
2.前后句关系平行一致
3.不可数名词，抽象名词不可用many形容
4.AlienX: "of XXX(年份)"在OG/Prep上常出现, 所以of previous year没问题
5.注意这个题的含义 (http://forum.Topway.com/GMAT_SC/thread-376052-1-1.html )：
不是说：今年的人数(total number)在增长以后，是去年增长人数（increase of the previous year)的两倍。
而是说：今年的增长(increase)是去年(increase)的两倍。
aeoluseros: 这里的double是"make twice as great"的意思，也就是使increase/growth两倍. (Explanation from LDOCE: “To become twice as big or twice as much or to make something twice as big or twice as much”)
AlienX: 我觉得doubling the increase of the previous year=使1990年的increase在the increase of（更多外语考试资讯尽在http://waiyu.kaoshibaike.com） the previous year的基础上倍增.
来看另外一个非常像的句子:
P1#242: Retail sales rose 8/10 of 1 percent in August, intensifying expectations that personal spending in the July-September quarter would more than double the 1.4 percent growth rate in personal spending for the previous quarter.
同理, personal spending in the July-September quarter would more than double the 1.4 percent growth rate in personal spending for the previous quarter=personal spending in the July-September quarter的growth rate在the 1.4 percent growth rate in personal spending for the previous quarter的基础上倍增.
6.Double和twice都可以直接作为predeterminer(如C,D,E选项)，而doubling中的double是作为及物动词(如A,B选项).
