How beautifully she sings! I have never heard________.

A．the better voice

B．a good voice

C．the best voice

D．a better voice

就刺激经济活动和调节社会生活的税收支出而言，不可以采取（）手段。

A.征税

B.税收豁免

C.优惠税率

D.纳税扣除