新prep98 1-179 both和each的问题

sad0oo

Unlike George in 1968 and JohnAnderson in 1980, both of whom running as independent candidates, H. RossPerot's independent run for the presidency in 1992 arose not from anunsuccessful effort to gain a major party nomination but from a desire toestablish a viable third party in American politics.
A.    George in 1968 and John Anderson in 1980, both of whom runningas independent candidates,
B.    George in 1968 and John Anderson in 1980, each of whom ran asindependent candidates,
C.    George in 1968 and John Anderson in 1980, both of which ran asan independent candidate,
D.     the independentcandidates, George in 1968 and John Anderson in 1980,   (E)
E.    the independent candidacies of George in 1968 and John Andersonin 1980,
答案为E,对此没有疑惑，大平行对称。我的疑惑点是搞不清楚ABC选项里面，both,each,whom,them的区别以及在这里的用法。笔记上说whom引导定语从句故需要谓语动词，那么them是名词性从句吗，them用在这是做什么用的呢？另外，both,each在这是怎么用的呢？请教大家，谢谢！！

sad0oo

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sad0oo

是我的问题太简单了么。。。