OG15 定从清晰的问题?!

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

OG: and because it provides a structure in which the relative clause beginning which may be violent clearly modifies mood swings.

看了以前大家的讨论,也没有明白为什么这里不加which引导的从句会不清晰, 假设乎虑perhaps这个用词不当的问题, 请教大家!

感谢!

还是把解释贴全吧

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.

红色的部分就是我不理解的,请教!!!

C和D归根到底是比较which may be violent和which are perhaps violent的异同。may对某事物不确定的推测，包含对该事物将来的行为的预期。are perhaps是用perhaps修饰一个对事物状态属性的陈述，表示这个陈述的不确定性，不自动包含该事物将来的行为的预期。如：I may be late = (I am or am not late + I will or will not be late), 不等于I am perhaps late，也不等于I am maybe late。

由此看来，情态动词一般不随便改动是有道理的。

至于ETS说它awkward，可以理解为ETS对perhaps的这个词的嫌恶了。

那请问问什么说是:less clear than the more developed clause which may be violent.呢？

感谢！

The relative clause begun with “which” normally modifies the antecedent that is immediately ahead of the word “which” (sometimes there is a comma between them). Thereby, you can tell that the relative clause typically modifies a particular part, say a word or a phrase, of the previous sentence. The specimens in which “which” refers to the previous sentence are considered ungrammatical, although they are quite usual in our daily life.   

As such, a relative clause is clearer, let me put it in another way, is more developed than an adjective phrase when both of them are used to modify a part of sentence. Since adjective phrase occasionally serves as the function of parenthesis and parenthesis is weaker in modification.

Good Question. 回帖，只有回帖，才是最好的学习方法，呵呵。我们简化一下B：

   Dr. F disutinguishes between MS, perhaps violent, and genuine MDP

这里perhaps violent悬在句中，可以看成which are perhaps violent作定语修饰MS，也可以看成插入语，或变成说Dr. F disutinguishes between MS这件事violent，也可能误会成说Dr. F is violent。总之在GMAT SC中非限定性定语从句，省略关系代词得异常谨慎。象这种系表结构的非限定性定从，省得只剩一个形容词的还不歧义的，个人没有见过。如有例外，请指出。

另外，不同意NN joel1说violent...是同位语的说法，因为同位的两个词的词性必须相同，形容词一般不能作名词的同位语。