A/ chia thì.....

    2  hadn't finished

    3 did

    5 arrived .....had watched

    6 what did you do at this time....

        we collected....

     7 have been

     8 asked...didn't want.....waited

    9 have seen

B chuyển sang bị động

  1 this house was bought 2 years ago by my father

2 these exercises had been done carefully by us

3 car is recycled tires to made pipes

4 a new school will be built in my town by the workers

5 the Chrismas carol was wrote in the 19th century by franz grunber 

7 english is spoken in the world

8 the classroom window had broken by the boy

9 his letter was got this morning by me

10 these cars are made in Japan

11 this bridge was built towe years ago