请教弱语法问题

kelvingg

1） 新东方语法分册section21 第11题，为何选E而不能选A或B
此题刘振民的解释是E9-47 :E中是两个地点状语的比较，among和 in，
但是，A B选项也有among 和 in ,为何不是地点状语的比较？
2） 新东方语法分册section21 第16题，如何得出正确答案？为何用完成时？
3） 新东方语法分册section21 第17题，如何得出正确答案？为何不能选C
多谢指教

kelvingg

感谢热心的各位：
附上SECTION21原题，及个人理解，请大家指教：
11. Some psychiatric studies indicate that among distin-
  guished artists the rates of manic depression and major
  depression are ten to thirteen times as prevalent as in
  the population at large.

   (A) the rates of manic depression and major depres-
       sion are ten to thirteen times as prevalent as in
   (B) the rates of manic depression and major depres-
       sion are ten to thirteen times more prevalent
       than in
   (C) the rates of manic depression and major depres-
       sion are ten to thirteen times more prevalent
       when compared to
   (D) manic depression and major depression are ten to
       thirteen times as prevalent when compared to
   (E) manic depression and major depression are ten
       to thirteen times more prevalent than in
16. New techniques in thermal-scanning photography, a
   process that records radiation from surface areas,
   makes it possible to study the effects of calefaction,
   or warming, of a river in greater detail than ever
   before.

   (A) makes it possible to study the effects of calefac-
       tion, or warming, of a river in greater detail
       than ever before
   (B) make it possible to study, in greater detail, the
       effects of calefaction, or warming, of a river
       than ever before
   (C) have made it possible to study in greater detail
       than ever before the effects of calefaction, or
       warming, of a river
   (D) make possible the study of the effects of calefac-
       tion, or warming, of a river in greater detail
       than it ever was before
   (E) has made it more possible than ever before to
       study in greater detail the effects of calefaction,
       or warming, of a river
此题先用主谓一致排除AE,因其宾语较长，故用形式宾语IT,排除D,且D的用法
possible应放到宾语之后，C理解更流畅

17. Bob Wilber became Sidney Bechet’s student and
   protege when he was nineteen and, for a few years in
   the 1940’s, came as close to being a carbon copy of
   the jazz virtuoso in performance as anyone has ever
   come.

   (A) as anyone has ever come
   (B) as anyone ever had been
   (C) as anyone ever had done
   (D) that anyone ever did
   (E) that anyone ever came
从句意上理解应是：比得上有史以来的任何人，故只能选has ever come