3. An accident has been reported on the road to Sa Pa by the police

→cấu trúc: S + have/has been + Ved/pII + ... + by O(s)

4. The park is being expected to be recognised as a World Heritage site by UNESCO next year

→cấu trúc: câu gốc: S + be + V_ing

                   câu chuyển đổi: S + be  + being + Ved/V3

5. The rule of the game will be claimed to be complicated 

→cấu trúc: S +will be + V3 (+ by sb/ O )

6. Trang An scenic landscape complex is known to be selected for fliming "Kong: Skull Island"

7. Son Doong cave is believed to be one of the largest caves in the world

8. One million foregin tourists were estimated to have been visited Viet Nam in December 2015

→cấu trúc: (6), (7), (8)

People/they + think/say/suppose/believe/consider/report…..+ that + clause
⟶ It+ to be + thought/said/ supposed/believed/considered/reported…+ that + clause hoặc
⟶ S + to be + thought/ said/supposed… + to + V-inf

3. It has been reported that there is an accident on the road to Sa Pa.

4. It is being expected that the park will be recognised as a World Heritage Site by UNESCO next year.

5. It will be claimed that the rule of the game is too complicated.

6. It is known that Trang An Scenic Landscape Complex was selected for filming “Kong: Skull Island”

7. It is believed that Son Doong Cave is one of the largest caves in the world.

8. It was estimated that one million foreign tourists visited Viet Nam in December 2015.

People/they + think/say/suppose/believe/consider/report…..+ that + clause
⟶ It+ to be + thought/said/ supposed/believed/considered/reported…+ that + clause hoặc
⟶ S + to be + thought/ said/supposed… + to + V-inf