`1.` A dancing class was started last week.

`-` Bị động thì QKD 

`-` Cấu trúc: S + was/were + VpII + (by + O) + time.

`-` Chủ ngữ câu bị động là đại từ nhân xưng (I, you, we, they, he, she, it) `->` Chuyển sang câu bị động thì có thể ko cần dùng (by + O)

`2.` The accident was seen by Mr. Smith.

`-` Bị động thì QKD

`-` Cấu trúc: S + was/were + VpII + (by + O) + time.

`-` see - saw - seen

`-` Chủ ngữ số ít `->` Đi với tobe "was"

`3.` My briefcase has been taken.

`-` Bị động thì HTHT: 

`-` Cấu trúc: S + have/has + VpII + (by + O) + time.

`-` Chủ ngữ câu chủ động là các đại từ bất định (somebody, someone, anyone, anybody,...) `->` Chuyển sang câu bị động thì có thể ko cần dùng (by + O)

`4.` Our written work was returned to us by the teacher. 

`5.` The report has been finished by noon.

`6.` The little boy was bitten by the mad dog.

`-` bit - bit - bitten 

`7.` Five suspects have been arrested by the police. 

`-` BĐ :

`+` QKĐ : S + was / were + VpII ( by O )

`+` HTHT : S + have / has + been + VpII ( by O )

`1`.A dancing class was started last week

`2`.The accident was seen by Mr.Smith

`3`.My briefcase has been taken

`4`.We were returned our written work by the teacher

`5`.The report has been finished by noon

`6`.The little boy was bitten by the mad dog

`7`.Five suspects have been arrested by the police

`\text{# TF}`