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4. Lan's friends are going to be invited to her birthday party.
5. The door of the classroom couldn't be opened by Lien.
6. That news should be announced as soon as possible.
7. The scientific book has to be returned to the library by Phong.
8. That old building must be repaired.
9. The memorial monument will be rebuilt by the government.
10. Phong may be elected their leader by the students.
11. Papers written in pencils won't be accepted by the teacher.
12. Some interesting places might be visited by the athletes after Sea-Games.
13. Their house has to be cleaned up by Lan's parents before Tet holiday.
14. She might be interviewed by the principal.
15. Fruit must be kept in the fridge for long.

X/
1. Th window was broken and some pictures were taken away by the boys.
2. I'll go by train and I will be met at the station by my friend.
3. A notice about the trip on the notice board was put up yesterday.
4. This problem is going to be explained to us by the teacher.
5. How much were you paid?
6. The suspects are being followed by the police.
7. I have just been told about it by a woman I know.
8. The dam may be broken by a sudden increase in water pressure.
9. Nothing isn't known about Brenda's family.
10. It is believed that air pollution is going to be much worse in the next decade.
11. He was said to have swallowed a safety pin.