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Here is a detailed explanation to this question-
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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
Meaning is crucial to solving this problem:Understanding the intended meaning is key to solving this question; the intended meaning of this sentence is that physicians have determined that stomach ulcers are not caused by stress, alcohol, or rich foods; rather, they are caused by a bacterium that dwells in the mucous lining of the stomach.
Concepts tested here: Meaning + Idioms + Parallelism• “not A but B” is a correct idiomatic usage; A and B must be parallel and comparable.
A: This answer choice fails to maintain parallelism between A ("caused by stress, alcohol, or rich foods") and B ("a bacterium that dwells in the mucous lining of the stomach") in the idiomatic construction "not A but B"; remember, “not A but B” is a correct idiomatic usage; A and B must be parallel and comparable.
B: This answer choice fails to maintain parallelism between A ("caused by stress, alcohol, or rich foods") and B ("are by a bacterium that dwells in the mucous lining of the stomach") in the idiomatic construction "not A but B"; remember, “not A but B” is a correct idiomatic usage; A and B must be parallel and comparable.
C: Correct. This answer choice correctly maintains parallelism between A ("by stress, alcohol, or rich foods") and B ("by a bacterium that dwells in the mucous lining of the stomach") in the idiomatic construction "not A but B". Further, Option C uses the phrase "stress, alcohol, or rich foods", conveying the intended meaning - that stomach ulcers are not caused by
any of the following elements - stress, alcohol, and rich foods.
D: This answer choice fails to maintain parallelism between A ("by stress, alcohol, and rich foods") and B ("a bacterium that dwells in the mucous lining of the stomach") in the idiomatic construction "not A but B"; remember, “not A but B” is a correct idiomatic usage; A and B must be parallel and comparable. Further, Option D alters the meaning of the sentence through the phrase "stress, alcohol, and rich foods"; the use of "and" incorrectly implies that stomach ulcers are not caused by a
combination of stress, alcohol, and rich foods; the intended meaning is that stomach ulcers are not caused by
any of the following elements - stress, alcohol, and rich foods.
E: This answer choice fails to maintain parallelism between A ("by stress, alcohol, and rich foods") and B ("are by a bacterium that dwells in the mucous lining of the stomach") in the idiomatic construction "not A but B"; remember, “not A but B” is a correct idiomatic usage; A and B must be parallel and comparable. Further, Option E alters the meaning of the sentence through the phrase "stress, alcohol, and rich foods"; the use of "and" incorrectly implies that stomach ulcers are not caused by a
combination of stress, alcohol, and rich foods; the intended meaning is that stomach ulcers are not caused by
any of the following elements - stress, alcohol, and rich foods.
Hence, C is the best answer choice.All the best!
Experts' Global Team