同义句转换（每空一词）
【小题1】It is thought that pollution is a very serious problem in the city.
Pollution ________ ________ ________ ________ a very serious problem in the city.
【小题2】It is reported that police are looking into this case at present.
Police are reported ________ ________ ________ ________ this case at present.
【小题3】At the end of the meeting, it was announced that an agreement had been reached.
At the end of the meeting, ________ ________ ________ ________ to have been reached.
【小题4】It is said that the new policy on the examination reform will be introduced soon.
________ ________ that the new policy on the examination reform will be introduced soon.
【小题5】It is said that the early European playing cards were designed for entertainment and education.
The early European playing cards are said ________ ________ ________ ________ for entertainment and education.