distinguish ... from ... 从...中辨别出...
distinguish between ... and ... 在两者间区分
原文表达的意思是两者间的比较，不能用from。
15. In his research paper, Dr. Frosh, medical director of the Payne Whitney Clinic, distinguishes mood swings. which may be violent without their being grounded in mental disease, from genuine manic-depressive psychosis.
(A) mood swings, which may be violent without their being grounded in mental disease, from genuine manic-depressive psychosis
(B) mood swings, perhaps violent without being grounded in mental disease, and genuine manic-depressive psychosis ,
(C) between mood swings, which may be violent without being grounded in mental disease, and genuine manic-depressive psychosis
(D) between mood swings, perhaps violent without being grounded in mental disease, from genuine manic-depressive psychosis
(E) genuine manic-depressive psychosis and mood swings, which may be violent without being grounded in mental disease
The best choice is C because it uses the idiomatically correct expression distinguishes between x and y and because it provides a structure in which the relative clause beginning which may be violent clearly modifies mood swings. The other choices use distinguishes in unidiomatic constructions. Additionally, their in A is intrusive and unnecessary, and the modifier of mood swings in B and D (perhaps violent) is awkward and less clear than the more developed clause which may be violent.
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