OG12 81题请教一下

12711399

Recently physicians have determined that stomach
ulcers are not caused by stress, alcohol, or rich foods,
but a bacterium that dwells in the mucous lining of the
stomach.
(A) not caused by stress, alcohol, or rich foods, but
(B) not caused by stress, alcohol, or rich foods, but
are by
(C) caused not by stress, alcohol, or rich foods,
but by
(D) caused not by stress, alcohol, and rich foods, but
(E) caused not by stress, alcohol, and rich foods,
but are by

正确答案是C，我知道是idiom的问题，但是我想问下省略的问题
以下补上省略后
stomach ulcers are caused not by stress, alcohol, or rich foods,
but
stomach ulcers are caused not by stomach ulcers a bacterium
如果不去掉NOT的话不第二部分不符合逻辑，但是我记得好像BY之前的都不能去掉了 如果subject and verb are shared.

sisichen666

LZ嘛意思？？？？not...but....并列啊。。。。
stomach ulcers are caused not （by stress, alcohol, or rich foods）,
but （by stomach ulcers a bacterium ），是by部分的平行。。。。