нужно из activ voice сделать  passiv voice
 1) police are investigating the accident
2) volunteers has organized the donation 
3) our goverment had changed some points in the Law of Education
4) they wil post the letter and the parcel tomrrow

1) The accident is being investigated by police.2) The donation has been organized by volunteers. 3) Some points in the Law of Education had been changed by our goverment.4) The letter and the parcel will be posted tomorrow by them.