________with his parents that he is able to tell who they are from their steps.     [ ]

A.  So familiar her is                            

B.  So familiar is he    

C. So he is familiar                              

D. So is he familiar

有线电视系统设备中，主要由放大器、混合器、分配器天线放大器、信号处理器等器件组成的设备为（）。

A.天线接收与分配系统

B.前端设备

C.信号传输分配系统

D.后端设备