请问：
13. State officials report that soaring rates of liability insurance have risen to force cutbacks in the operations of everything from local governments and school districts to day-care centers and recreational facilities.
(A) rates of liability insurance have risen to force
(B) rates of liability insurance are a force for
(C) rates for liability insurance are forcing
(D) rises in liability insurance rates are forcing（C）
(E) liability insurance rates have risen to force
虽然这里因为对FOR和OF的选择就可以选了C，我还是想问一下OG中的这句，In A and E, it is redundant to say that soaring rates have risen. 为什么选ARE FORCING 要比HAVE FORCING 好呢？一个报告也可以是报道一个已经发生了的事呀？
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（C）
(E) genuine manic-depressive psychosis and mood swings, which may be violent without being grounded in mental disease
对于这句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
又一点不明白。查了一下字典，DISTINGUISH A FROM B也是对得呀？要是A选项中，without their being grounded 的THEIR除掉，是不是这个选项也是对的呢？
谢了 | 
