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
"those" is wrong. The only noun in plural form is "young adults". So in D you are comparing young adults with young adults. However, this question is not about absolute[\b] number, but the comparative number --percentage. In E, the number and 20% are comparable.
以下是引用mindfree在2004-1-4 11:27:00的发言: However, this question is not about absolute[\b] number, but the comparative number --percentage. In E, the number and 20% are comparable.