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 modifier of mood swings in B and D (perhaps violent) is awkward and less clear than the more developed clause which may be violent. perhaps與may be的問題好像在之前都沒解決,難道真的就是ETS不喜歡perhaps就都不用嗎?? 有沒有其他的解釋呢?

太绝对了. OG11th里有perhaps作对的答案, 忘了哪一题. 找到了再给你补上.

这里我觉得which的定从比形容词的插入语好. 而且perhaps这种副词一般修饰动词.

may be

1, possible. (可能）

2, it's going to be.（可以是）

just my 2 cents.