That was the first time I _______ there and I was impressed by the friendly people very much.

A．go

B．was going

C．had gone

D．have gone

两个电容串联，C1容抗为5Ω，C2容抗为10Ω，则（）

A.总容抗小于10Ω

B.总电容小于10Ω

C.C1电容量较C2电容量大

D.容抗与频率无关