1, It is believed that English is the most widely spoken language.
English is believed to be the most widely spoken language.
2, It has been reported that it was Peter who caused the accident.
Peter has been reported to have caused the accident.
3, It was thought that the teenagers were dancing at the disco.
The teenagers were thought to be dancing at the disco.
4, It is thought that she sings beautifully.
She is thought to sing beautifully.