Sentence Correction

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

[spoiler] Answer is C. B is wrong, but would replacing "are" with "caused" create a parallel structure? Thus the sentence would be:
Recently physicians have determined that stomach ulcers are not caused by stress, alcohol, or rich foods, but caused by a bacterium that dwells in the mucous lining of the stomach.
[/spoiler]

the right idiom here will be not by .... but by

so C will be my answer

OneTwoThreeFour wrote: Answer is C. B is wrong, but would replacing "are" with "caused" create a parallel structure? Thus the sentence would be:
Recently physicians have determined that stomach ulcers are not caused by stress, alcohol, or rich foods, but caused by a bacterium that dwells in the mucous lining of the stomach.

Yes, replacing "are" with "caused" still results in a parallel structure. Consider the idiom "not X, but Y" it is important that X and Y be the same parts of speech. In this case, X would be "stress..." while Y would be "bacterium.." As you can see, they're both nouns and are parallel, which is why C is the correct choice.

thanks gtestprep!

gtestprep wrote:

OneTwoThreeFour wrote: Answer is C. B is wrong, but would replacing "are" with "caused" create a parallel structure? Thus the sentence would be:
Recently physicians have determined that stomach ulcers are not caused by stress, alcohol, or rich foods, but caused by a bacterium that dwells in the mucous lining of the stomach.

Yes, replacing "are" with "caused" still results in a parallel structure. Consider the idiom "not X, but Y" it is important that X and Y be the same parts of speech. In this case, X would be "stress..." while Y would be "bacterium.." As you can see, they're both nouns and are parallel, which is why C is the correct choice.

I know the causedcan be omitted in the second part. My question is in choices C and D and E, what is the right order of caused and not?
Thanks in advance!

not and by are two element of comparative.

we focus on these elements and solve the matter quick.

ceilidh.erickson wrote:

Crystal W wrote: I know the causedcan be omitted in the second part. My question is in choices C and D and E, what is the right order of caused and not?
Thanks in advance!

Hi Crystal,

The answer to your question is... both orders are correct! It just depends on the structure of the rest of the sentence. When the structure is NOT X... BUT Y, then the X and the Y must be parallel. In other words, whatever comes immediately after NOT must match what comes immediately after BUT:

The flood was caused not by rain but by snow melt. --> Correct.

The flood was not caused by rain but caused by snow melt. --> Correct.

The flood was not caused by rain but by snow melt. --> Incorrect.

The flood was caused not by rain but caused by snow melt. --> Incorrect.

The same will be true any time you have two-part parallel markers:
NOT ONLY X... BUT ALSO Y
BOTH X... AND Y
EITHER X... OR Y
NEITHER X... NOR Y

Thank you very much! It is really clear!