they didn't invite ann to their party did they build the house in 1980 someone was following me at 10.00 last night they have changed the date of the meeting the room looked much better . someone had cleaned it

`1.` Ann wasn't invited to their party.

`-` Bị động 2 tân ngữ, didn't `->` thì QKĐ : was / were + Ved/Vp2

`-` Có thể lược bỏ by them

`2.` Was the house built in 1980?

`-` Y/N questions thì QKĐ ( dhnb : did ) : Was/ Were + S + Ved/Vp2 ( by O )?

`3.` I was being followed at 10.00 last night.

`-` Bị động thì Quá Khứ Tiếp Diễn ( was following ) : S + was/were + being + V3/ed + (by + O) 

`-` Có thể lược bỏ by someone

`4.` The date of the meeting has been changed ( by them ).

`-` Bị động thì Hiện Tại Hoàn Thành ( have changed ) : S + has/have + been + V3/ed + (by + O)  

`5.` The room had been cleaned ( by someone ) so it looked much better.

`-` Bị động thì Quá Khứ Hoàn Thành ( had cleaned ) : S + had + been + V3/ed + (by + O)

`-` Có thể lược bỏ by someone