____ the telephone number several times, but he couldn't learn it by heart. [ ]

A. Having told                    

B. Having been told

C. Although he had been told        

D. He had been told

在税法体系中具有最高法律地位和最高法律效力的税法是（）

A.税收实体法

B.税收程序法

C.税收通则法

D.税收单行法