OG12-81

movingever

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.

• not caused by stress, alcohol, or rich foods, but
• not caused by stress, alcohol, or rich foods, but are by
• caused not by stress, alcohol, or rich foods, but by
• caused not by stress, alcohol, and rich foods, but
• caused not by stress, alcohol, and rich foods, but are by

答案C
很多比较两者的句子里，动词可以省略，如果我把A答案的最后加上“by”是不是就对了？

liuqiaoqi77

我觉得A如果在后面加上BY，也是对的。

xinxiangwei

这里是习语是not A, but B, 其中A,B要平行对称。
A中如果要使其对的话，必须改成not caused by stress, alcohol, or rich foods, but caused by这样才对，加一个by不能解决问题。

Sunfisher006

这个不能确定，能否找出省略的例子研究一下

elvisc

OG 的解釋是: A To preserve parallelism, but should be followed by by.

所以我覺得這裡的平行應該跟not 的位置沒有關係.