Since 1986, when the Department of Labor began to allow investment officers' fees to be based on how the funds they manage perform, several corporations began paying their investment advisers a small basic fee, with a contract promising higher fees if the managers perform well.

(A) investment officers’ fees to be based on how the funds they manage perform, several corporations began

(B) investment officers’ fees to be based on the performance of the funds they manage, several corporations began

(C) that fees of investment officers be based on how the funds they manage perform, several corporations have begun

(D) fees of investment officers to be based on the performance of the funds they manage, several corporations have begun

(E) that investment officers' fees be based on the performance of the funds they manage, several corporations began

解释中说ABE三个选项中的they都指代不明，这是什么意思呢？they在这三项中可以指代那些名词呢？有关指代的语法规则是什么呢，请大牛指教。为什么正确选项中的they指代就明确呢？

they从单复数来将可以指代funds, officers, fees里的任何一个.

判断代词的指代对象比较困难, 因为没有公理可寻, 通常是根据逻辑. 但有一点是肯定的, 那就是代词一定不能指代所有格. ABE中officers' fees里面fees是中心词, officers是所有格. 而这句句子根据逻辑判断, 但词只能指代officers, 所以ABE因此被排除. CD中的officers是中心词, 所以指代相对(我只能说相对)比较明确.

通过排除得到答案后我可以这样分析, 但在做题时我也是靠比较答案的其他区别得出结论, 因为尽量不要靠指代确定选项.