高一定语从句(急) who() has feet can run so fast

问题描述:

高一定语从句(急) who() has feet can run so fast
who() has feet can run so fast
a.which
b.who
c.whom
d.that
请说明为什么

应选D. 因为若主句中有疑问代词 who 或者 which,为了避免重复, 关系代词不要再用 who, which,而用 that.
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