OG 15

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.

The answer is C. That's ok.我想问的是如果把D改成

between mood swings, perhaps violent without being grounded in mental disease, and genuine manic-depressive psychosis ，是不是也对呢？什么时候用从句修饰，什么时候用短语呢？有什么区别？

个人观点也许是可以的。通常which be的结构被认为是可省的，但这里有个may, 把它换成perhaps后二者谁更优我说不清，可能还是前者。至于什么时候用从句修饰，什么时候用短语，这对我而言同样是难点，我的感觉根据具体情况来判断，如果区别不出，那看看两个选项有无其他不同，总之答案是比出来的。

原句中的情态动词尽量保持（在保证语法和逻辑正确的前提下），D中的perhaps不合适；

个人意见。

1. may be 不能换成perhaps, 根据liuzhenmin语法，情态动词尽量不变化。

2。 如果把句子变成您说的那个样子，不知它应该在整个句子中充当什么成分。所以我觉得不可以。

个人意见，如有不对，请指教！

1, may 不能改为perhaps ,因为这是情态动词

2用短语表达按OG的说法有点修饰不清