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

那位给讲讲？我选的B

逻辑上, that沒有指任何東西
如果LZ觉得有, 你可以试一下把那个被指的東西replace "that", 你会发现, 都是逻辑不通.

A. doubling the increase of

B. doubling that of the increase in   that没有指代

C. double as much as the increase of  double+noun；数字能用much修饰吗？问

D. twice as many as the increase in   many错

E. twice as many as the increase of  many错