Chuyển sang câu bị động : 

1) He is running his own restaurant ? 

=>His own restaurant is being run (by him)

2) The secretary opens the mails every morning

=>The mails are opened by the secretary every morning

3) The teacher doesn't allow me to take the seat by the window

=>I am not allowed to take the seat by the window by the teacher

4) Tom's  absence worried his mother

=>Tom's mother was worried by his absence

5) They are building a new school in this town

=>A new school is being built in this town

6) You should finish the report right now

=>The report should be finished (by you) right now

7) Are you going to post this letter ?

=>Is this letter going to be posted (by you) ?

8) He has pay the bills before the fifth of the month 

=>The bills have to be paid by him before the fifth of the month

9) No one has opened that box for the past hundred years

=>That box hasn't been opened for the past hundred years

10) The enemy used to it take the bag

=>It used to be taken the bag by the enemy

11) The fire has destroyed many houses

=> many houses have been destroyed by the fire 

12) The children are carrying the chairs in to the house

=> the chairs are being carried into the house by the children