求助 蓝皮203-5 关于指代不清的问题

In large doses,analgesics that work in the brain as antagonists to certain chemicals have caused psychological disturbances in patients,whch may limit their potential to
        relieve severe pain.

(A)which may limit their potential to relieve

(B)which may limit their potential for relieving

(C)which may limit such analgesics' potential to relieve

(D)an effect that may limit their potential to relieve

(E)an effect that may limit potential of such analgesics for relieving

答案是E

我选了D

我觉得E好象太wordy了

不选D我觉得应该是their的指代不清,但其实这里的指代还是比较清楚的...

想请教一下大家什么时候判断为wordy,什么时候是指代不清....

不选D我觉得应该是their的指代不清,但其实这里的指代还是比较清楚的...

=〉do not assume

咱中国人太聪明了没办法，一看就知道指代哪个，可是老外不同，前面那么多个复数名词，老外看了会傻眼的....

OG对这样的选项一般的解释是指代不清，有时候详细一点的解释就是指代的词和代词隔得太远

至于wordy，应该没有一个统一的框架去套吧...

请教一下困扰我很久的问题，到底什么算指代不清呢？请问their有可能代替下面的哪些名词?

analgesics that work in the brain as antagonists to certain chemicals have caused psychological disturbances in patients，an effect that may limit their potential to relieve

my opinion：这个句子里their优先指代patients的。对于指代analgesics的几率与指代chemicals，disturbances  和antagonists 的几率一样大。

另外 limit their potential to relieve的意思不是很明显是：限制它们的潜能是为了减轻痛苦吗？A,B,C,D都范了这个错误

只有E把这个用法用对了。