Reduce these following relative clause using to-infinitive or participle. 9. All students don’t hand in their papers will fail in the exam. 10. I saw many houses that were destroyed by the storm. 11. The street which leads to the school is very wide. 12. The system which is used here is very successful. 13. Mr.John, who teaches my son, is my neighbour. 14. Trains which leave from this station take an hour to get to London. 15. The candidates who are sitting for the exam are all from Vietnam. 16. We are driving on the road which was built in 1980. 17. Customers who complain about the service should see the manager. 18. The city which was destroyed during the war has now been rebuilt. 19. My brother, who met you yesterday, works for a big firm. mình cảm ơn ạ