1. My uncle was lose his key.

-> His key was lost.

2. We gave our teacher a flower yesterday.

-> A flower was given our teacher yesterday.

3. He bought a chocolate box.

-> A chocolate box was bought.

4. Mai did her homework two days ago.

-> Homework was done two days ago.

5. Quang bought a lot of decorations last week.

-> A lot of decorations were bought last week.

6. Hang took some flowers on her table down.

-> Some flowers were taken on her table down by Hang.

=> Cấu trúc câu bị động:

      S + was/were + PII + (by.....) +.........

                                                        Cấu trúc:

                                            S+ tobe+v3+O
                                            S+ tobe not+v3+O
                                            
 - His key was lost by my uncle.
 - Our teacher a flower was given by us yesterday.
 - A chocolate box was bought by him.
 - Her homework was done by Mai two days ago.
 - A lot of decorations were bought by Quang last week.
 - Some flowers on her table down were taken by Hang.