纳税人端软件的业务功能有（）。
A.发票补打
B.发票填开
C.网络发票资格确认
D.空白发票异常报告
参考答案：A, B, D
–What did your parents think about your decision?
–They always let me do _______ I think I should.
A．when
B．that`
C．how
D．what
变频调速发展的趋势如何？
