介宾短语在句子做什么成分

wangjieava23

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

这里on domestic flights 是在修饰first class 吗？这个问题有些弱呀。

abc88

觉得是 修饰people的 ？？？！！ 在国内航班中坐头等舱的 人的数量。。。

wangjieava23

这样。我更糊涂了

abc88

我乱猜的 别信我~
是不是作状语  在国内航班中 然后 怎样怎样的···
别纠结了 略去算了

wangjieava23

再顶顶看吧，我真的对介宾的修饰困扰好久了。