._____he speaks softly is no proof that he is kind.  a.Since b.As c.That d.Because

问题描述:

._____he speaks softly is no proof that he is kind.
  a.Since b.As c.That d.Because

C that是代词 代替he speaks 的东西

c
That he speaks softly一整个从句作主语

选C
That 引导的主语从句,that 不做任何成分.