求翻译和讲解.She had said little so far,responding only when（ ）.A.speakingB.spoken toC.spokenD.speaking to 还有,以so far为标志词的不是要用现在完成时吗?这里怎么用过去完成时?帮我翻译一下句子,特别是后半句.谢谢!求逐项分析哦，特别是BC两项。

求翻译和讲解.She had said little so far,responding only when（ ）.
A.speaking
B.spoken to
C.spoken
D.speaking to
还有,以so far为标志词的不是要用现在完成时吗?这里怎么用过去完成时?帮我翻译一下句子,特别是后半句.谢谢!
求逐项分析哦，特别是BC两项。