把下列句子从被动语态转换成主动语态
1.complaints should be sent to the head office.
2.my examinations will be finished next week.
3.the car hasn't been sold yet.
4.the children are being driven to the park at this moment.
5.this door must be kept shut.
6.two bikes were stolen from school yesterday.
7.three teenagers have been arrested near metro disco.