Active: People say that he lives abroad now.
Passive1: It is said (by people) that he lives abroad now.
Passive2: He is said to live abroad now.
Active: We understand that he dislikes children.
Passive1: It is understood (by us) that he dislikes children.
Passive2: He is understood to dislike children.
In the above cases where a principal clause is followed by noun clause, the passive voice can be formed in the above two ways. I noted that in the first way the change is made only to principal clause and not the noun clause.
But then in a test I came across a question:
Active: We hope that we shall win the match.
Passive (my ans) : It is hoped (by us) that we shall win the match.
Passive (correct answer): It is hoped that the match will be won by us.
When to make changes to only the principal clause and when to both?