doubling用法讨论

dkswoah

According to surveys by the National Institute on Drug Abuse, about 20 percent of young adults used cocaine in 1979, doubling those reported in the 1977 survey.
(A) doubling those reported in the 1977 survey
(B) to double the number the 1977 survey reported
(C) twice those the 1977 survey reported
(D) twice as much as those reported in the 1977 survey
(E) twice the number reported in the 1977 survey

OA：E。其中twice跳跃used cocaine修饰20 percent of young adults.     这题选E  选A 问题出在哪里呢？

这道题和下面那道有很大区别么   those指代的是同名 不同一个  的物质  但是指代20 percent of young adults 是不合适的？
得用the number来比较？我这么解释 对么

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    (A)

E. twice as many as the increase of

这题就选A  doubling   难道说这是根据选项来的？   第二道题 因为BCDE有明显错误  B指代  in 得改成of    C PREP语法笔记上的解释感觉有点难懂，说double as much as是同位语 前面得有先行词  DE many就错了      所以只有A 还能凑合用？

kiwifoodtown

第一题，不能选A，those 是代词，指代什么？20 percent ？young adults？cocaine？指代不清，所以选E。

第二题，选A doubling这里是现在分词这里作状语，修饰主句。B选项 that of 指代不对。C选项的double as much as是同位语修饰词，前面必须有修饰对象，所以错。D,E many不能用于不可数名词，也错。