用户在一对电话线上同时开放ADSL业务和电话功能，按相应资费标准分别收取（）.

A、电话月租费

B、电话通话费

C、ADSL网络使用费

D、新业务费

Susan decided not to work on the program at home because she didn’t want her parents to know what she     .

A．has done

B．had done

C．was doing

D．is doing